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RMAN BACKUP AND RECOVERY PRACTICE WITH RAC AND ASM

Posted on 25. Mar, 2008 by sabin.

Check the configuration parameters of Rman.
Connect to Rman without catalog. Controlfile is used to store Rman metadata:
You need to set the environment before invoking Rman:
ORACLE_BASE=/u01/app/oracle
ORACLE_HOME=$ORACLE_BASE/product/11.1.0/db_1
ORA_CRS_HOME=/u01/app/crs
ORACLE_PATH= $ORACLE_BASE/common/oracle/sql:.:$ORACLE_HOME/rdbms/admin
ORACLE_SID=mars1

$rman target / nocatalog

RMAN> show all;

RMAN>exit;

———————————–

rmanbackupconf.sh

rman target / nocatalog <<EOF
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO ‘/orabackup/rman/%F’;
CONFIGURE DEVICE TYPE DISK PARALLELISM 2 BACKUP TYPE TO BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL 1 DEVICE TYPE DISK CONNECT ‘SYS/redhat@mars1′;
CONFIGURE CHANNEL 2 DEVICE TYPE DISK CONNECT ‘ SYS/redhat@mars1′;
CONFIGURE MAXSETSIZE TO UNLIMITED;
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM ‘AES128′; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO ‘/orabackup/rman/snapcf_racdbtst1.f’; # default
configure controlfile autobackup format for device type disk to ‘/orabackup/rman/ctrl/%F’;
configure channel device type disk format ‘/orabackup/rman/backup_db_%d_S_%s_P_%p_T_%t’;
exit;
EOF

————————————————————————————–

Check the archive log status and destination:

SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination +ORCL_DATA1
Oldest online log sequence 82
Next log sequence to archive 83
Current log sequence 83

Check existing tablespaces and datafiles:

SQL> select tablespace_name,file_name from dba_data_files;

TABLESPACE_NAME FILE_NAME
——————————
SYSTEM +ORCL_DATA1/mars/datafile/system.282.648988143
SYSAUX +ORCL_DATA1/mars/datafile/sysaux.283.648988181
UNDOTBS1 +ORCL_DATA1/mars/datafile/undotbs1.284.648988195
UNDOTBS2 +ORCL_DATA1/mars/datafile/undotbs2.286.648988247
USERS +ORCL_DATA1/mars/datafile/users.287.648988271
DATA +ORCL_DATA1/mars/datafile/data01.dbf
OBJECTS +ORCL_DATA1/mars/datafile/objects01.dbf
INDX +ORCL_DATA1/mars/datafile/index01.dbf

Create a test tablespace and a test table to be used to check Restore and Recover:

SQL> create tablespace recop1;
Tablespace created.
SQL> create table restable1 tablespace recop1 as select sysdate timestamp from dual;
Table created.

Check tablespaces and datafiles, note that all of them are located on ASM’s ORCL_DATA1 disk group:

SQL> select tablespace_name,file_name from dba_data_files

Check the timestamp we inserted on the test table, we will recover until this time later:

SQL> select * from restable1;
TIMESTAMP
—————–
01-02-07 15:49:06
————————————————————————————–

Execute backup using script

backup.sh
#!/bin/csh -x
# rman_backup_as_copy_to_FS
# —————————-
# 29-01-07 Alejandro Vargas
# —————————-
# This script make a backup copy to file system
# This backup can be restored on File system as a regular hot backup
# Or can be restored to ASM by using rman
# ——————————————————————————-
# This script does:
# 1) Administrative tasks:
# crosscheck
# delete obsolete
# 2) Archive log current on 1st Instance
# 3) Archive log current on 2nd Instance
# 4) Rman backup as copy to file system including controlfile and archivelogs
# 5) Archive log current on 1st Instance
# 6) Archive log current on 2nd Instance
# 7) Rman backup as copy archivelogs not backed up and print backupset list to log
# ——————————————————————————–
# This script works with 2 nodes only, if you have more than 2 nodes you need to customize it.
#
# This script use aliases and Environment variables set on .cshrc
# to setup the environment to point to the Database:
# setenv DBS_HOME /u01/app01/oracle/product/10gDB
# setenv BASE_PATH /usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin
# alias 10db ‘setenv $ORACLE_HOME $DBS_HOME; setenv PATH $ORACLE_HOME/bin:$BASE_PATH’
# This script do require as parameters the 2 instance names
# It will use them to archive all required logs from instances 1 and 2
# ——————————————————————–
set v_inst1=mars1
set v_inst2=mars2
# Rman Backup Location variable
# —————————–
set v_rman_loc=/orabackup/rman
# Step 1: Administrative tasks, crosscheck and delete obsolete
# ————————————————————
#10db
setenv ORACLE_SID $v_inst1
rman target / nocatalog <<EOF
crosscheck backupset;
crosscheck copy;
crosscheck archivelog all;
delete noprompt expired backup ;
delete noprompt obsolete;
exit
EOF
# This script run from 1st node. We use an external identified DBA user, ops$oracle, to execute
# the archive log current. From the same session we connect as ops$oracle into the 2nd instance
# You need remote_os_authent=TRUE on both instances to connect remotely without password
# Step 2: Archive log current on 1st Instance
# Step 3: Archive log current on 2nd Instance
# ——————————————-
sqlplus -s sys/pass@$v_inst1 as sysdba << EOF
select instance_name from v\$instance
/
alter system archive log current
/
connect sys/pass@$v_inst2 as sysdba;
select instance_name from v\$instance
/
alter system archive log current
/
exit
EOF
# On step 4 we use 4 channels. This needs to be customized according the number of cpu’s/IO
# channels available. Rman is invoked in nocatalog mode, we need to have configured
# ORACLE_HOME, ORACLE_SID and PATH on the environment, as we did in the previous steps.
# Step 4: Rman backup as copy to file system including controlfile and archivelogs
# ——————————————————————————–
rman target / nocatalog <<EOF
run {
allocate channel backup_disk1 type disk format ‘$v_rman_loc/%U’;
allocate channel backup_disk2 type disk format ‘$v_rman_loc/%U’;
backup as COPY tag ‘%TAG’ database include current controlfile;
release channel backup_disk1;
release channel backup_disk2;
}
exit
EOF
# Step 5 and 6: Archive log current on 1st and 2nd Instances
# ———————————————————-
sqlplus -s sys/pass@$v_inst1 as sysdba << EOF
select instance_name from v\$instance
/
alter system archive log current
/
connect sys/pass@$v_inst2 as sysdba;
select instance_name from v\$instance
/
alter system archive log current
/
exit
EOF
# Step 7: Rman backup as copy archivelogs not backed up and print backupset list to log
rman target / nocatalog <<EOF
backup as copy archivelog all format ‘$v_rman_loc/%d_AL_%T_%u_s%s_p%p’ ;
list backupset;
exit
EOF
# Redirecting rman output to log will suppress standard output, because of that
# running separately.
rman target / nocatalog log=$v_rman_loc/backupset_info.log <<EOF
list backup summary;
list backupset;
list backup of controlfile;
exit
EOF
# eof backup

————————————————————————————–

This script does:
1) clean up the catalog (crosscheck / delete obsolete)
2) archive log current on both instances
3) backup database as copy to File System
4) archive log current on both instances
5) backup as copy archived logs
6) log actual backups
See the Backup Log.
The Backup generated the following files:
Controlfile and spfile backup:
Datafiles:
Rman Backups list:
backupset_info.log
Backup log:
/tmp/rman_backup.err

Insert some other records into the test table:

Insert into the test table new rows,check its content:
SQL> insert into restable1 select sysdate from dual;
1 row created.
SQL> /
1 row created.
SQL> /
1 row created.
SQL> /
1 row created.
SQL> commit;
Commit complete.
SQL> select * from restable1;

SQL> alter system archive log current;
System altered.

Simulate a crash by manually deleting some datafiles:

Execute on both instances:
SQL> select instance_name from v$instance;
INSTANCE_NAME
—————-
mars1
SQL> shutdown abort
ORACLE instance shut down.
SQL> select instance_name from v$instance;
INSTANCE_NAME
—————-
mars2
SQL> shutdown abort
ORACLE instance shut down.

Inside ASM some files accidentally deleted!!!:

$asmcmd

ASMCMD> cd ORCL_DATA1/mars/datafile/

ASMCMD> ls

ASMCMD> rm USERS.264.606653719 <<<<< Note, only possible because the
ASMCMD> rm RECOP1.273.613410453 <<<<< Database is down!!!
ASMCMD> ls
ASMCMD> EXIT

$sqlplus / as sysdba

Enter user-name: / as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 96470608 bytes
Database Buffers 184549376 bytes
Redo Buffers 2973696 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 5 – see DBWR trace file
ORA-01110: data file 5: ‘+ORCL_DATA1/mars/datafile/users.264.606653719′

NOTE: Drop tablespace from inside the database is not recoverable with Rman; Rman will also deleted the backup copy of any deleted tablespace!!!!

—————————————————————————————

RECOVER PROCESS

Execute recover until time using the existing backup:
Set the database to work as single instance to perform the recovery and stop it:

SQL> show parameters cluster_database
NAME TYPE VALUE
———————————— ———– ——————————
cluster_database boolean TRUE
cluster_database_instances integer 2

SQL> alter system set cluster_database=false scope=spfile sid=’*';
System altered.
SQL> shutdown abort
ORACLE instance shut down.

Check the backup files and take note of the Database ID (highlighted):

$cd /orabackup/rman/

$ls

backupset_info.log
cf_D-MARS_id-1122898414_5djc2p5c
ctrl
data_D-MARS_I-1122898414_TS-DATA_FNO-6_4rjc2nqs
data_D-MARS_I-1122898414_TS-DATA_FNO-6_5ajc2p4e
data_D-MARS_I-1122898414_TS-INDX_FNO-8_4tjc2nr1
data_D-MARS_I-1122898414_TS-INDX_FNO-8_5cjc2p5a
data_D-MARS_I-1122898414_TS-OBJECTS_FNO-7_4sjc2nqu
data_D-MARS_I-1122898414_TS-OBJECTS_FNO-7_5bjc2p50
data_D-MARS_I-1122898414_TS-SYSAUX_FNO-2_4njc2nn7
data_D-MARS_I-1122898414_TS-SYSAUX_FNO-2_56jc2p08
data_D-MARS_I-1122898414_TS-SYSTEM_FNO-1_4ojc2nn9
data_D-MARS_I-1122898414_TS-SYSTEM_FNO-1_57jc2p0a
data_D-MARS_I-1122898414_TS-UNDOTBS1_FNO-3_4pjc2npd
data_D-MARS_I-1122898414_TS-UNDOTBS1_FNO-3_58jc2p33
data_D-MARS_I-1122898414_TS-UNDOTBS2_FNO-4_4qjc2npm
data_D-MARS_I-1122898414_TS-UNDOTBS2_FNO-4_59jc2p41
data_D-MARS_I-1122898414_TS-USERS_FNO-5_4vjc2nr8
data_D-MARS_I-1122898414_TS-USERS_FNO-5_5ejc2p5k
MARS_AL_20080324_52jc2ns2_s162_p1
MARS_AL_20080324_54jc2ns6_s164_p1
MARS_AL_20080324_5gjc2p80_s176_p1
MARS_AL_20080324_5hjc2p82_s177_p1
MARS_AL_20080324_5ijc2p88_s178_p1
MARS_AL_20080324_5jjc2p8a_s179_p1
MARS_AL_20080324_5kjc2p8c_s180_p1
MARS_AL_20080324_5ljc2p8e_s181_p1
MARS_AL_20080324_5mjc2p8h_s182_p1
MARS_AL_20080324_5njc2p8j_s183_p1
MARS_AL_20080324_5ojc2p8m_s184_p1
MARS_AL_20080324_5pjc2p8o_s185_p1
MARS_AL_20080324_5qjc2p8q_s186_p1
MARS_AL_20080324_5rjc2p8t_s187_p1

$rman target / nocatalog
Recovery Manager: Release 10.2.0.1.0 – Production on Thu Feb 1 16:34:20 2007
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database (not started)

RMAN> set dbid=-1122898414
executing command: SET DBID

RMAN> startup nomount;
Oracle instance started
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 96470608 bytes
Database Buffers 184549376
Redo Buffers 2973696 bytes

1) we do restore the controlfile from a time previous to the crash:

RMAN> restore controlfile from ‘/orabackup/rman/cf_D-MARS_id-1122898414_5djc2p5c’;
Starting restore at 01/02/2008 16:36:03
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=153 devtype=DISK
channel ORA_DISK_1: copied control file copy
output filename=+ORCL_DATA1/mars/controlfile/current.256.606653653
Finished restore at 01/02/2008 16:36:20

2) we mount the database:
RMAN> mount database;
database mounted
released channel: ORA_DISK_1

3) we set until which time we want to recover, using the ‘set until time’ clause, the we do restore and recover, in this example the three commands are passed to Rman within a single block:
RMAN> run { set until time=”to_date(’01-FEB-08 16:14:28′,’DD-MON-YY HH24:MI:SS’)”;
2> restore database;
3> recover database; }

executing command: SET until clause
Starting restore at 01/02/2008 16:40:26
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=148 devtype=DISK
allocated channel: ORA_DISK_2
channel ORA_DISK_2: sid=153 devtype=DISK

Finally we need to restablish Cluster Mode and open both instances.
1)Mount instance 1 and set cluster_database=true :
SQL> show parameters cluster_database
NAME TYPE VALUE
———————————— ———– ——————————
cluster_database boolean FALSE
cluster_database_instances integer 2
SQL> alter system set cluster_database=true scope=spfile sid=’*';
System altered.
SQL> shutdown immediate
ORACLE instance shut down.

2) Restart the database in cluster Mode:
srvctl start database -d mars
srvctl start service -d mars
crs_stat –t
chkcrs

3) Check restore point on test table:
SQL> select * from restable1;
TIMESTAMP
—————–
01-02-08 15:49:06

http://www.comp.dit.ie/btierney/Oracle11gDoc/server.111/b28301/backrest002.htm

Continue Reading

My Oracle Notes

Posted on 07. Mar, 2008 by sabin.

Orac is the creation of a dedicated group of volunteer programmers led by Andy J. Duncan. Some of the major contributors include Kevin Brannen and Thomas Lowery, but many others too numerous to mention have contributed as well. A list of most of the contributors is included in the README file that accompanies the program. You can find out more about Orac, including installation hints and tips and mailing list information, from the Orac home page listed below.

http://technet.oracle.com/linux/: Oracle’s Linux home page

http://www.tux.org/dclug/oracle/index.htm: “Presentation: Oracle Database Administration on Linux”

http://linuxworld.com/linuxworld/lw-1999-06/lw-06-oracle.html: Installing Oracle on Linux

http://jordan.fortwayne.com/oracle/: Installation hints and tips

http://www.kkitts.com/orac-dba/: Orac Home Page/Mailing List Information

http://www.symbolstone.org/technology/perl/DBI/index.html: Information on Programming with DBI/DBD

ftp://ftp.funet.fi/pub/languages/perl/CPAN/authors/id/A/AN/ANDYDUNC: Download the Orac software here.

http://www.lazydba.com/: Oracle DBA site, scripts and tips

BEA’s WEblogic, Iplanet Application Server, WEbSphere,Oracle Application Server, Macromedia JRun, Persistence’s PowerTier, Brokat’s Gemstone/J,HP’s Bluestone,IONA’s IPortal,Borland’s AppServer and the JBoss application server
Togethersoft’s Together/J and Rational’s Rational Rose

set wrap off

select table_name from user_tables;

show all

set linesize 80

set pagesize 24
set time on

Oralce Instance(exits in memory )

Buffers
Processes
Files
Network communication

___________________________________________________
Oralce Instance
___________________________________________________
ProcessLayer
___________________________________________________
Memory layer(Sga -shared Area)
_________________________________
Databse buffers            | Database writer
redo log buffer            | log write
sort buffer            | archiver
shared pool            | pmon smon
Parsed sql and pl/sql    |
latches and locks    |
metadata        |
___________________________________________________

Datafiles, redologs,archivelog, controlfiles,config files
____________________________________________________
Networking configuration and process

Simple Data Types

[n]varchar2(n) Variable length string up to 4000

[n]char(n) Fixed length string up to 2000 charaters

number(p,s) Precision=number of character, scale= number of decimal places p=1 to 38 s=-84 to 127

float(p) A floting poin or real number. p=1 to 126

Integer Creates number(38 , size 38 character number field

Smallint create number(38), size 38 characters number field

Date stored as Juian date in seconds containing year month, day, hours, minutes, seconds to 100th precision

timestamp(p) precision is scale in fractions of a second thus timestamp(2) stores 10th of a second

BLOB=large video ,picture text sound in binary format
CLOB= large text doucumet
NCLOB

complex data types

REf pointer refencinge another object

bfile pointer including full path and file name to a file stored externally to the database. Typically used for multimedia objects

Nested Table Dynamic or variable length arry used for creating user defined data types

varray(n) fixed length arry used for creating user defined data types

Xml storage and direct xml document retrieval

Spatial GIS and CAM sysstem geometric modeling data storage

Media Multimedia storage

Any Generic daa type storage

=================================================
types of tables
Relational tables
Object table
Temporary table(one session cannot see another’s data)
index organized table(table+indexcolum)
cluser(join multiple table into single)
exernal table(store externaly in file)
XML type table (store xml document)
Partitionaled table
(Partition or split a single tables into multiple tables places on different disk)

==================================================
set timing off
spool log\createuser.log;
create user sabin identified by shrestha
default tablespace data
temporary tablespace temp
quota unlimited on data
quota unlimited on INDX
quota unlimited on objects
quota unlimited on temp;
grant connect,resource to sabin;
grant unlimited tablespace to sabin;
grant query rewrite to sabin;

spool off;
exit;
===============================
Create global temporary table shows(act varchar2(64),
venue varchar2(64))
on commit preserve rows;
=====================================
Type of Indexes
Btree(Binary Tree)
Bitmap(for multidedia file)
function Based
Index Organized Table
Cluster
Bitmap Jion
Domain(for picture goematical)

====================
Acending or decending
uniqueness
composites
compression
reverse key indexes
sorting(no sor)
nall values

primary and unique are created internal index foregin key are not created

create index on foregin key
create index ind1 on show (act_id asc);
alter index ind1 rebuild

===============================
sequence
create sequence test_seq start with 1 increment by 1
nomaxvalue nocycle;
=========================================
Synonyms
another name for table
create or replace public synonym [schema.]synonym
for [schema.]object
================================
metadata
allviews
userviews

Purpose
Interrogation
maintenance
performance

select table_name from all_tables;
select table_name from dba_tables;
select table_name from user_tables;
validation
dba vies

V$ performance views

user_objects
usertables
user_indexes
user_clusters
user_lobs
user_sequences
user_sysnonyms
user_views

table index and cluster columns
user_tab_columns
user_ind_columns
user_clu_columns

constraints
user_constraints
user_cons_columns

user defined types
user_nested_tables
user_varrays

privileges
user_role_privs
user_sys_privs
user_tab_privs

pl/sql
user_procedures
user_triggers
user_triggers_cols
user_source

user_users
user_errors

Error messages in oracle websites
====================================================
Schemas and users
schemas schematic
Ceteral area to store table stuructre and data

users can be looks at single schema
users and schema is same

System previleges(create table index sequence)
object privileges(alreday created privileges)
column privileges
views
the virtual private database

Groupings
Roles
public and security

Special Roles
dbi
selectcatlog

sharing resources and profiling
user_role_privs
user_sys_privs
user_tab_privs

connect sys@s as sysdba
desc role_sys_privs;

types of users
Database Administrators
=====================================

Security Administrators
Network Administrators
System Administrators
Applications Developers
Testing
Prower Users
End Users

sqlplus sys@intserver @a.sql

revoke connect from developer;
grant create session to developer
===============================
dbausers
system
sys

previlies
sysdba sysoper

system privileges
object privileges

====================
database and sysem
sysdba and syoper
database links
rollback segments
sessions
tablespaces
analiyze
grant

=======================
roles alter any drop any,grant any
session create,alter
users create,alter,drop

==============================================================================================

JOins
Cross Join /cartesian product
Natural /innerjoin
outer join(left right full)
self join
eqi/anti/range join
mutable/complex join

=====================================

==============================
rollup
cube
grouping sets(filter on rollup and cube)

group by rollup(v.name);
group by cub(v.name,a.name);
group by grouping sets((v.name,a.name),(a.name),(v.name));

group by grouping sets((v.name,a.name),(a.name));

group by grouping sets((v.name,a.name));
==================================
subquery tune the select command

Single Query
categoryid=(select)

Multiple Row
categoryid IN(select)

Multiple Column
and(s.show_id,s.venue_id) in(select showid,venue_id from ticket)

regular
caegory_id in(1,2,34,5);

correlated
where exists(select category_id from show where category_id=c.category_id);

exists is fast then in()

data is low then in
data is hight then use exists

Conditional Comparisions
(subquery) [= != > < >= <=] (subquery)
(subquery) [not]like (subquery)
(subquery) IN (subquery)
[NOT] Exists (subquery)
(subquery) between(subquery(sigle row ret)) and (subquery(sigle row ret))

(subquery) [= != > < >= <=] [any some all] (subquery(multipule row))

Hierarchiacal Queries
familytree(tablename)
name             father      level
william ford1             1
john ford    williamford1   2
willam ford II   john ford      3
henry ford       william ford II 4
edsal ford       henry ford    5

select name ,father,level from familytree
start with name=”William Ford I’
connect by prior name=father;

sets opeator and composit Queries
Union all all rows from both queies including duplicates

insert
update
deleted
merge (new data is inserted,already existing data will be updated)

Transactions(block of dml command)
commit and rollback
set transation
commit rollback(end transation
savepoint(label to return block structure)

truncate table test

merg
merge 2 tables

merge into category c
using newcategory nc
on(c.category_id=nc.categoryid)
when matched then
updae set c.name=nc.name
when not matched then
insert valued (nc.categoryid,nc.name,nc.parentid);

=====================================================

Create database
shared pool 128 Mb
buffer cache 64
javapool=0
largerpool=8
pga=0

DbSizing
sort Area size 32 K

create achive mode

Tablespace
remoove tools
remove users
and add data
(locally manged
automatic

redo log
18 redo log files
all 10 Meg

datadistnory is saved in system tablespace

parameterfile in
ora92\database
initprod.ora
ifile=’e;\oracle\admin\prod\pfile\init.ora’

4 Memory Structure

System Global Area
show sga
desc v$sgastat
select * from v$sgastat

javapool=0
Databse Buffer Cache(cpu and disk io buffer management)
Multiple Buffer Cache

Shared Pool
Library Cache
metadata or Dictionary Cache
v$librarycache
v$rowcache

redo log buffer

large pool

Session conections
Program global Area(PGA)
Shared Servers(MTS)

Java pool(java store procedure)

Processes
Server Processes(executed by client in server)
Dedicated Server
Shared Server
Dispatcher

client Connection Proc
Background Processes(executed by oracle)
System Monitor (SMON)
Maintain of Physcial space, temprory spaces and recovery)clean of work
Process Monitor(PMON)
Monitor process ,and fail clean up client connection is broken then clean it free it

Database Writer
communication between databasebuffer and disk, ditry block is data that is changed

Log Writer
write log entry into redo log file

ARcn
same as log write but it copies and write redo log file into archive log file such cyclic redo file can be re used again

Datafile Tablespaces and Object
Tablespaces
is a logical low level object which includes data files(logical wrapper of datafiles)
can contain multiple datafile orcle can contain multiple table spaces

Datafile is file that is stored in os as a file which contains database information,tablerow indexes datadictionary

Schema
is a schematic, digram,plan or container or defination of things
defination of owner or usernames
usernames contains tables logical object or logical overlays over physical structure of datafile
schema and tablespace are not directly related
schema can make user of multipule tablespaces
and tablespaces can contain multiple tablespaces

Segment
object defined within schema
physical information within that object actual data with in table
schema define defincation contain bucket for putting data
segment is physcial area occupied by the data

Schema contain table
segment is data within the table

extent
is physical chunk added onto datafile as the data file grows
added automatically as define sized defined in database
571QYuge1C0
phicial chuk is added to allow to add more rows related to schema and datafile

below extent lowest it is block
smalleset phiysical chuck within oracle database datafile segment index table

large block is usefull when reading whole table
samll block is usefull when reading single row

Controlfiles and recoverability
Logging
it contains a bunch of pointer to other things
logging is can be used to remcover before 1days 1 weeks using pointers
redo log file is used to cycle when they are completed they are copied to archive log
archive log is historical log

insert: row+rowid
update:changes|rowid
delete: rowid
ddl activity
Not everything must be logged(indexes)

Records transations in redo log files
Archiving
stores old redo log files
Recoverability
is control by controlfile
pointer to logs and datafiles (physical location,files)
syncronsize between to logs and datafiles
logs+archives
datafiles

Commit and rollback
commit store changes to database
rollback is to undoo
savepoint
transaction control
set transaction

before commit or rollback
database is changed
log is written
rollback is written

on commit
rollback is deleted
rollback writes changes to redo logs

on rollback
rollback applied to database
rollback recorded is logs
rollback is deleted
rollback writes changes to redo logs

(redo logs contain record of both changes and rollback undo)

Manul rollback
undo_management=manual

rollback is maunal
specify and build rollback segments

undo is automated rollback
rollback is information used to undo the the changes of databases which not yet commited

undo
undo_management=auto
automatic rollback management

when rollback manual
tuning rollback segments
oldtp= small and many
Minimize Transactions/RollbackSegment

Undo
in period of time for which alredy committed rollback information is kept or retain
used for flashback it is based for period of time

desc dba_tablespaces; tabespace_name,contents
Tomporary tablespaces sort spaces
workarea_size_policy
sort_area_size
sort_area_retained_size

auto can also used as dedicated not is shared
pga_aggregated_target

installation

lsnrctl
status

emca

db_create_file_dest ( destination of datafile)
db_create_oneline_log_dest_n (1 to 5) (duplex)

parameter file
OFA
oracle Flexible Architecture
is a directory structure

oradim -new -sid test -intpwd password -maxuser 2 -startmode auto -pfile c:=oracle\admin\prod\pfile\init.ora
create tns
syslplus /nolog
connect sys/password@test as sysdba

lsnrctl stop
lsnrctl start
tnsping

oradim -delete -sid test

orapwd

============
starting up and shutting down a database
select * from v$database
sqlplus /nolog
sqlplus sabin/hello@test @a.sql

startup
nomount mount
open read write readonly recover
force restrict pfile=paramenter

shutdown
normal
transactional
immediate
abrot

select name,open_mode from v$database

shutdown normal;

shartdown nomount don’t not open ctrl file redologfile tablespace etc

startup restrected (any dba can connected)
select * from v$pwfile_users;
allow shutdown and start from os

restrict when user’s have session restricted privilased can login

select username from dba_users;

grant restricted session to sabin;

revoke restricted session from sabin;

starup pfile=

shutdown
shudwown after all users logged off no further connections

shutdown transactional when sql execution is finish
shutdown immediate shutdown after all users forcibly disconnted all transacton forcib rollback
shutdown abort terminates the instance

combining startup and alter database
startup nomount
alter database mount
alter database open

Configuration Parameter
textbase
parsed on database statup

binary file
can be altered online
alter system set

set pages 500;
select named,value from v$parameter order by 1
alter system set trace_enabled=true

classifying parameters
DAbase and instance identification
controlfiles
database cahce and i/0
shared memory
server
connection
The optimizer
logs and recovery
rollback and undo
sql * net
diagnostics, tracing and statics

remote_login_passwordfile=EXCLUSIVE

controlfiles
control_files=(“c;\oacle\oradata\prod\control01.ctl”,
“d;\oacle\oradata\prod\control01.ctl”,
“e;\oacle\oradata\prod\control01.ctl”)

db cahce and i/0

db_file_multiblock_read_count=32

db_block_checking=TRUE
shared_pool_size=128 M
shared_pool_reserved_size=4M
large_pool_size=8M rman backup
log_buffer=131072 recycle buffer of memory for redo log

processes=200
job_queue_processes=25

tuning
hash_join_enable=true
query_rewrite_enable=true
query_rewrite_enable=true
query_rewrite_integrity=trusted
star_transformation_enabled=true
parellel_automatic_tuning=true
compibility=9.2.0.1.0

undo_management=AUTO
undo_retention=900

sql * net
dispatcher=”(protocal=tcp) (dispatchers=1) (port=1521)”
shared server=2
circuits=5
shared_server_session=5
max_shared_server=5
max_dispatcher=3

sql_trace=true
max_dump_file_zie=1M
statistics_level=typical

alert_log (very import )

mts multi threaded server

===================
alter database to modify the physical database

starting and shuting database
datafiles
tempfles
logfiles and archives
controlfiles
defaults

alter database default temporary tablespace temp

create temporary tablespace temp2 tempfile
‘e:\oracle\oradata\abc\temp02.dbf’ size 10M
extent management local uniform size 1M;

alter database default temporary tablespace temp2

desc v$datafile;
select file#,name from v$datafile;

alter database datafile “e:\oracle\oradata\prod\tools01.dbf” offline
recover datafile
alter database rename file “e:\oracle\oradata\prod\tools01.dbf’ to ‘e:\oralce\oradata\prod\rman01.dbf’
alter database datafile “e:\oracle\oradata\prod\rman011.dbf” online

desc dba_data_files

select autoextensible,maxbytes/1024/1024,increment_by,file_name from dba_data_files;

select bytes/1024/1024 ,name from v$datafiles

alter database datafile “e:\oracle\oradata\prod\tools01.dbf’ resize 20M

select name from v$tempfile
select table_name from dictionary where table_name like ‘%TEMP%’;

desc dba_temp_files;
select file_name from dba_temp_files;

select name from v$datafile
union
select name from v$tempfile

alter database tempfile
alter database datafile

control file (standby and backup)
backup control files
alter database backup controlfile to ‘e:\oracle\oradata\prod\control01.bak’
alter database backup controlfile to ‘e:\oracle\oradata\prod\control01.bak’ reuse

shutdown immediate
copy of control to different drive
change the paratemer file

to update binaryfile
edit in e:\oracle\ora92\database
abc.ora

startup nomount pfile=e:\oarcle\admin\prod\pfile\init.ora
shutdown immediate
create spfile=’e:\oracle\ora92\database\spfileabc.ora form pfile=’e:\oracle\admin\proc\pfile\init.ora

redo log files
select * from v$logfile
select * from v$log

alter database add logfile ‘e:\oracle\oradata\prod\redo04.log’ size 10M;
alter database add logfile ‘e:\oracle\oradata\prod\redo05.log’ size 10M;

select * from v$logfile

select * from v$log

alter system switch logfile
alter system switch logfile

explain current, active and inactive status

alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;

alter database add logfile ‘e:\oracle\oradata\proc\redo01.log’ size 10M reuse
alter database add logfile ‘e:\oracle\oradata\proc\redo02.log’ size 10M
select * from v$logfile
select * from v$log

duplex log file
alter database add logfile member ‘f:\oracle\oradata\proc\redo01.log’ to group 1
alter database add logfile member ‘f:\oracle\oradata\proc\redo01.log’ to group 2
alter database add logfile member ‘f:\oracle\oradata\proc\redo01.log’ to group 3
alter database add logfile member ‘f:\oracle\oradata\proc\redo01.log’ to group 4
alter database add logfile member ‘f:\oracle\oradata\proc\redo01.log’ to group 5

select * from v$logfile
select * from v$log

select table_name from dictionary where table_name like v$archive%’;

alter system
archive log list
alter system archive log stop;
archive log list
alter sytem archive log start
alter sytem switch log file

alter system flush shared_pool;

desc v$archive_log;
select name from v$archive_log;

Session
desc v$session
select username,sid,serial$,status from v$session;
alter system kill session ’12(sid),37(serial)’;
alter system kill session ’12(sid),37(serial)’ immediate;

alter system set trace_enabled=false;
alter system set db_cache_size=20M
select name,value,isdefault from v$parameter

automated undo and rollback
select name,value from v$parameter;

shutdown immediate
edit text parameter file
comment 3 parameter
rollback_segments(rb00,rb01,rb02,rb03,rb04,rb0,rb05,rb06,rb07,rb08,rb09); create 50
startup pfile=e:\oracle\admin\prod\pfile\init.ora;
select name,value from v$paramenter

create tablespace rbs datafile ‘e:\oracle\oradata\prod\rbs01.dbf’
size 50M autoextend on minimum extent 1M
default storage (initial 50M next 1M minextents 50 maxextents unlimited);

create rollback segment rbtemp tablespace system storage(initial 64k next 64k extents 300);
alter rollback segment rbtemp online

create public rollback segment rb00 tablespace rbs storage (initial 16k next 16K extens 15k);
alter rollback segment rb00 online
repeat for till rb09

select segment_name,status from dba_rollback_segs;

meta dataview
v$performace

mounted mode just attached control file to database
desc v$datafile
desc v$tabalespace;
des v$controlfile_record_sections;
des v$log
desc v$logfile
desc v$archive_log;
select table_name from dictionary

Ddl and logical database(container of data)

controlfile
redologs / | \ Archive logs

on the top of the physical database we get Table space

tablespaces(logical)(group datafiles)
|
multiple datafiles in a tablespace(phiysicl)

database object are stored via tablespaces and datafiles
database object and tablespaces are logical structure overlayed in datfile physical structure

Database Objects
Table
Index
cluster
sequence
synonym
view
type
procedure

Tabalespace Management(2 type)
Dictionary(stored as metadata)
Local
desc dba_tablespaces;
select tablespace_name,block_size,status,contents from dba_tablespaces;

select tablespace_name,extent_management,segment_space_management from dba_tablespaces;

db_cache_size=25165824
db_2k_cache_size=4M
db_16k_cache_size=4M

statup pfile=e:\oracle\admin\prod\pfile\init.ora
create spfile=’e:\oracle\ora92\database\spfileabc.ora’ from pfile =’e:\oracle\admin\prod\pfile\init.ora’

shutdown immediate

desc v$tablespace

============
Expanding Database Object for Database Administration
Creating table
Select table space
organized using Index (IOT)
Storge
initi Size 1 MB
netsize 1 Mb
increase size by 0 %
minimun number 1
maximum number unlimeted
umber of transation
initital 1 maximum 255
buffer pool default

Option
Parellel

Caching option
palce frequent accessed data to the top of the bufer cache
monitoring option
Monitoring

Creating altering and dropping indexes(physical aspect of index)

create table actname cluster test(col) as select name from act

undrop table dropped table [as new table];

purge
{table dropped table |index dropped index}
{dba_ recyclebin}
{tablespace tablespace [user user] }};

select * from user_recyclebin;

Partitioning
chuck of physical data space split into multipulte chuk
range partition
list partition
hash partition
composite partition
range-hash
range-list

Partitioning Indexing
Local index

Globale index

partitioning tricks
add drop and truncate
split and merge
rename
move
exchange

Range Partition
Create table rangepartitiontable(
… columns and constraints…)
Partition by range (dte)(
partition dataglp1999 values less than
(To_date(’2000-03-01′,’YYYY-MM-DD’)) tablespace dataglp1999
,partition dataglp2000 values less than
(To_date(’2001-03-01′,’YYYY-MM-DD’)) tablespace dataglp2000
,partition dataglp2001 values less than
(to_date(’2002-03-01′,’YYYY-MM-DD’))Tablespace DATAglp2001
,partition dataglp2002 values less than
(maxvalue) tablespace dataglp2001);

Partition Indexing
create index fkx_glp_1 on glp(coa#) tablespace indx;
create index lk_glp_1 on glp(dte,coa#) local(
partition indxglp1999 tablespace indxglp1999
partition indxglp2000 tablespace indxglp2000
partition indxglp2001 tablespace indxglp2001
partition indxglp2002 tablespace indxglp2002);

List Partition
create table Listpartitiontable(
…. columns and constraints…)
partition by list(type)(
partition purchases values (‘P’) tablespace datatsp
,partition sales values(‘S’) Tablespace datatss);

Hash Partition
create table hashpartition table(
…. columns and constraints..)
partition by hash(order_id) partitions 3
store in(dataol1,datao2,datao3);

range hash composite partition
create table rangehashcompositepartition table(
… columns and constraints..)
partition by range(dte) subpartition by hash(generalledger_id)
subpartitions 4 store in (sp1,sp2,sp3)
(partition dataglp1999 values less than
(to_date(’2000-01-01′,’YYYY-MM-DD’)) tablespace dataglp1999
,partition dataglp2000 values lessthan
(to_date(’2001-01-01′,’YYYY-MM-DD’)) tablespace dataglp2000
,partition dataglp2001 values lessthan
(to_date(’2002-01-01′,’YYYY-MM-DD’)) tablespace dataglp2001
,partition dataglp2002 values lessthan
(maxvalue) tablespace dataglp2002);

range list composite partition
create table rangelist compositepartitiontable(
generalledger_id number not null
,coa# char(5) not null
,dr number(10,2) not null
,cr number(10,2) not null
,dte date not null)
partition by range(dte) subpartition by list(coa#)
(partition dataglp1999 values less than
(to_date (’2000-01-01,’YYYY-MM-DD’)) tablespace dataglp1999
(subpartition assets1999 values(’20001′,’20002′);
,subpartition liabilities1999 values(’10001′,’10002′);
,subpartition expenses1999 values(’50001′,’50002′);
,subpartition income1999 values(’60001′,’60002′);
,partition dataglp2000 values less than
(to_date(’2001-01-01′.’YYYY-MM-DD’)) tablespace dataglp2000
(subpartition assets2000 values(’20001′,’20002′)….

dba_tables
dba_index
desc user_tables
user_indexes
desc user_clusters;
user_sequences;
user_tab_columns;
user_ind_colums;
user_constraints;

user_cons_colums

set wrap off linesize 132 pages 80;
column pos foramt 990;
column col format a10;
column ind format a25;
column tab format a25;
column typ format a20;
column tbs format a25;

select t.table_name “Tab”
,decode (t.index_type,’NORMAL’,'BTree’,'BITMAP,’Bitmap’,'FUNCTION-BASE NORMAL’,'Function-based Btree’,t.index_type) “typ”
,T.INDEX_NAME “IND”
,C COLUM_NAME “COL”
,c.column_position “pos”
,t.tablespace_name “tbs”
from user_indexes t, user_ind_columns c
where t.table_name =c.table_name
and t.index_name =c.index_name
and t.index_tpe not in (‘IOT – TOP’,'LOB’)
order by t.table_name, t.index_name, c.cloumn_position;

alter index abc rebuild online tablespace indx;

set wrap off linesize 132 pages 80;
column key foramt a10;
column pos format 990;
column col format a15;
column cons format a20;
column tab format a20;
column own format a10;

select decode(t.constraint_type,’P”,’Primary’,'R’,'Foreign’,'U’,'altenate’) as key
,t.table_name “Tab”
,t.constraint_name “cons”
,c.column_name “col”
,c.position “Pos”
from user_constraint t, user_cons_columns c
where t.constraint_type in (‘P’,'R’,'U’)
and t.table_name-c.table_name
and t.constraint_name =c.constraint_name
order by t.table_name, t.constraint_type,c.position;

database security

type os users
Database Administrators
security Administrators
network Administrators
system administrors
application developers
testing
power users
endusers

granting privileges

create user concerts identified by concerts
default tablespace data
temporary tablespace temp
quota unlimited on data
quota unlimited on indx
quota unlimited on objets
quota unlimited on temp;

system=metadata
tables and indexes are separated since both are read concurrently
temp sort space

Dba users
system
sys

Administrator Privileges
as sysdba or sysoper

select * from v$pwfile_users;

revoke sysoper from test
grant sysdba to system;

select * from v$pwfile_users;

sqlplus /NOLOG
connect sys/test@test as sysdba
startup

orapwd

privileges
system privileges

REsources and profiles

rosource limits

processor time
allocation profile userss

i/o amount ======
allocation

concurrent sessions profiles usersss
idel time
connection time
shared server
per-parsed sql
space limitation

Database Auditing
Statement Auditing
privilege auditing
object auditing

Scheduling
every 1 second
declare
jobno number;
i integer default 1;
begin
for j in 1..25 loop
dbms_job.submit(jobno,’testproc;’,sysdate,’sysdate+1/86400);
end loop;
commit;
end;
/
select job,log_user “user”,last_sec “prev”, this_sec “curr”,next_sec “next”, failures ,
from user_jobs;

declare
cursor cjobs is select job from user_jobs;
begin
for rjob in cjobs loop
dbms_job.remove(rjob.job);
end loop;
end;

utilities
export help=y
import help=y

sqlldr help-y

sqlldr userid=user/password
discardmax=2 errors=10000000
direct=true
data=data/data.txt control=ctl/data.ctl
log=log/data.log bad=bad/data.bad
discard=dsc/data.dsc

data.ctl
load data
infile ‘data/data.txt’
into table atable
truncate
fields terminated by ” ”
trailing nullcols
( col1 char(32)
,col2(char(128)
,col3 integer external defaultif duration=blanks
)

value1 value2 0

orapwd help=y

buildin packages
packages
dbms_job
dbms_output

===============================================================
Oracle Certification IZ0-032

Oracle Net Services Architecture
Listener
Connection String and Naming Methods
Oracle Shared Servers
Connection Manager
Oracle Net services Utilities

Types of Backups
Types of Recovery
physical Backups using datafiles
RMan (Recovery manager)

Standy and Replication
Transportable Trablespaces
sql * loader

technet.oralce.com

Transportable Tablespaces
Sql * loader (utilities)
Utilities

Introduction to Oracle Net Services
Server
listner
Server Processes
Client configuratio
Naming Methods
Web & Application Servers

Client/Web Application-Server
Oracle shared Server(MTS)
Large Network configurations
connection manager
oracle Names
ldap
Host and external Naming ? (novel)

Options for Managing Oracle database network
Local and Centralized Naming
Large Networks
Dedicated and Shared Servers
connection Sharing
connection Profiles
Standardizing Configuration

Multiple Listeners
Load Balancing
Multiple Protocols
Connection Cencentration
connection Pooling

Listener Timouts and queue size
SDU Buffer Size
Trobleshooting

Oracle Enterprice Manager
Oracle Agent
The Management Server

Local versus centralzed Naming
Local is taking to listener directly
is controlby tns
transparent Network substrate
Configuration
Simple
listener.ora
tnsnames.ora
sqlnet.ora (profile and information)

Centrilized Naming
Methods
HostNames
External Software (novel)
Oracle Names Server
LDAP
Connection Manager

Configuration
Can be hightly complex
many configuration files
multiple machines
large networks

Simple server configuration
where are the configuration files>
c:\oracle\ora92\network\admin

what are the configuration files?
listener.ora
sqlnet.ora
tnsnames.ora
snmp_ro.ora ( for oracle agent process)
snmp_rw.ora

Oracle Shared Server or (MTS)
sharing of connection
Configuration Parameters

c:\oracle\admin\master(database)
initMaster.ora
#sql * net
dispatchers=*(protocol=TCP) (Dispatchers=1) (port=1521)”
shared_servers=2
circuits=5
shared_server_session=5
max_shared_servers=5
max_dispatchers=3

Connection Profiles sqlnet.ora(standarized connection) this option is overwrited of clients
TCP.NoDELAY=YES
user_DEDICATED_SERVER=yes
sqlnet.expire_time=5
network outage Detection
oracle 10g

Introduction Naming Option

local naming
tns names.ora

Directory Naming (LDAP)
looking in ldap server like dns server

Oracle names
like dns server

hostnames

externaling Names like novel

oracle Connection Manager
connection concentration
funneling or Multiplexing
Multiple Protocol Support
specific configuration
cmadmin (processes)
cmgw

Backup and recovery
Logical backups
export (dump tablespace and schema definition and data)
import (to import)

Pysical Backups
cold backups (shutdown database)
offline
Hot Backups
online (tablespace offline copied individually)
individual tablespaces
RMan
automate locagial and physical backup

standby (physical(read only) or logical(rw))

Replication
oracle repliction
oracle Streams and Advance queuing
Materialzed Views

clustering

Mirroring
Raid Arrays
Operation System

Transportable Tablespaces

sql * loader
=================

Import and exprot
copies of
individual
Tables
schemas
full database (not good_
can be
consistent
tuned
transportable Trablespaces (make use)

Cold Backups
shutdown database
copy
datafiles
controlfiles
archivelogs
Not required
redo logs(used by duplixing)
optional
network files
prarameter file
binary password file

restart Database

Hot Tablespace backup(online)
database is in open
individual datafile is in backup mode(offline) any changed into redo log files
when when done the redo log is writethem back to tablespace and datafile
larger data file longer time
if large slow down
don’t switch all tablespace do one by one
switch one tablespace offline backit up and make it online one by one

redologs are covered by duplixinge
control files are backup using alter database command
copy archive logs

Data files copied individually
changes written to redologs during tablespace backup
when the table space is switch online
changes writen to datafile from redo logs after tablespace backup

RMan
Recovery Manager
Advantages
Complex Management
fewer Human errors
scalability
incremental backup
reliability
incremantal
faster

disadvantanges
planned as oralce standard
requires backup of itself
can use controlfile
repository loss
catastrophic loss
power User Tool(small amount of thinking)

redo covered by duplexing
Archive logs no longer needed are destoryed
only new archives
control file contain simple repository
repositary placed into rman specific database
requires independent offline backup (table space backup mode_
databse resitory stores references and scripting

easier and safer

Recovery

restore copying file in os datafile
recover restore datafile 1 week ago upto
an including all changed made in any of redolog and archive redo logs

taking the datafile and upding all changed that repleid after the was backup made

contol file has pointet to each of the datafile
pointer or changeno for redo and archive logs
if the redo logs has pointer value is which is later than restored data file
then the control file or database knows that data file is restored
is behind in changes with are record in redo logs same applied to archive logs

if poiner value in rodo log is later than datafile then control file is telling database
there is extra changes which should be applied to datafile those changes will be applied until
datafile is uptod date with redologs changes full update

Archive redo log if changes are so far behind in restored datafile it is possible they could also
retrive from archive redo log

archive logs can be deleted pirior to previous datafile backup

Standby database
standby is to take over failover production database
copy the archive log to standby database
automated
copies log entries
at archiving

9i complex
2 form
physical standby
readonly mode

logical (rw)

physcial standby
Easy to Implement
easto to mange
inaccessible Managed Recovery mode
readonly
self contained
entire primary database only
copy data physicaly and maintain physically

logical standby
difficult to implement
difficult to mange
readwire capable
not only for backup
not self contained
can add new objec to stadby
cannot change primary objects from standby
erors more likely
can operate on subset of Primary Database
can duplicate schemama not entirely database

Replication
highly complex
duplicating changed into slave
very detailed
difficul to implement
innappropriately used
Distribution of processing
not backup & recovery

type of replication
one direction only
master and slave one way

unidirectional
master to master

Replication by other Means
oracle streams
pipline between 2 database
database
>
apply queue
^
oracle stream
^
capture queue
^
database

Advance queuing
Master to Master capable
multiple daabase capable
distributed Enviromenents
Materialized views (snapshot)
one way
master to slave only
Manually using Coding
scary

Transportable Tablespaces

tablespace can be transport one database to another (same version)

copy datafile of tablespace and copying to new database
logal export and import utility to copy itt
unpluging from one database and pluging to another database

sql * loader
utitily to rapidly take falt file or external define file
and pass them using control files applyng and formating
syntax to data in flat and external file into database
no need to use dml

fata data load
pre-configuration and automation
very large amount of data

data warehouse
full command line syntax copability
oracle enterprise manger
special loading
direct appending
parrell processing
external table and flat files

Oracle Net Service Architecture
Open Systems Interconnection Model
Oracle’s OSI Model
Protocols
communication
dedicated and shared connections
shared server processes and dispatchers

the OSI Model
www.iso.org

oracle osi Model
client stack
Clinet Application Layer
oci(oracle call interfce) define server call ,syntax parsing validation ,squel curor, variable binding,execute sql statemnt, fetch it’s rows and close the cursor,or as single or group of messages like procedure
TTC(two task common) datatype converstion
net8 layer (session,transport) network interface,network naming/ network session,network route,network Authentication)
oralce Protocal Adapter
oralce Protocal Adapter(tcp,sll, spx namedpipes )
Netork specif Protocols(physical layer)

server stack
opi(oracle program Interface)(exec request,prarse, format,translate the restult to oci later)
TTC (two task common) data type conversion
net8 layer (session,transport) ntwork interface,network naming/ network session,network route,network Authentication)
oralce Protocal Adapter(tcp,sll, spx namedpipes )
Netork specif Protocols(physical layer)

Protocols
TCP/IP
Bequeath(same server and client)
Others
sPX,Named piped,

Dedicated and shared Connections
Server Processes
Dedicated

shared
overide from client

Dispatchers
the dispatch messages and request user shared server process

The listener

internet users
|
dispatcher
/            \
Sshared server proc        shared server processes
\             /

Database
/          \
dedicated         deicated
/              \
client         client

dedicated and shared server are server processes

listener sit between client and server processing

shared server process and dispatchers

========================================
tnsnames.ora
tnsping sabin

profile parameter file
slnet.ora
NAME.directory_PATH= (TNSNames,Onames)

Basic Databse configuration Parameters
dispatchers=”(Protocol=tcp) (dispatchers=1) (port=1521)”
shared_servers=2
circuits=5
shared_server_sesson=5
max_shared_server=5
max_dispatcher=3

Listener
over network
for request
Prasses request to
server process
dispatchers
Possible changes
queue size
logigng and tracing
multiple listners
loadbalancing
timeouts
SDU buffer

lsnrctl
help
status
stop
start
services

show
show trace level
show log_status

to disbale logging
in listener.ora

logging_listener = off
trace_level_listener = off
connect_timeout_listener = 30

logging_listener1 = off
trace_level_listener1 = off
connect_timeout_listener1 = 30

lnsrctl
start listener
start listener1

loadbalacing
failover(taf)
(Load_balance=yes)
failover=yes

SDU Buffer
session data unit buffer
buffer flushed to network when full
(big transton large buffer samall transtion low buffer)512byte 32kb
(SDU= 32768)

connecton profile configuration
oracle_home/network/admin/sqnet.ora
profile apply to all users
spceif to client computer

priorize Naming
logging and tracing
routing
external naming
advaced security features

Connecton String and naming methods

connect <username?/password @
(description=(protocol=tcp)
(host=<hostname>(port=1521))
connect_data=
(service_name=PROd.xyz.com)))

Naming Methods
localnaming
host naming
external naming
ldap
oralce naming(onames.ora)

oracle Shared Servers
multithreaded server(mts)
shares server processes
connections share proceses
allocates using dispatcher processes

Introuction Dispatchers
Data base configuraiton prameters
the most Important Ones
dispatchers
shared_servers

Dispatchers=”(Protocol=TCP)(DIspatchers=1)(port=1521)))
shared_servers=2
circuits=10 (buffer )
shared_sever_session=10
max_dispatchers=3
max_shared_servers=5

Dispatchers=”(Protocol=TCP)(DIspatchers=1)(port=1521)(queuesize=50)))
(session=500)
(connections=500)
multiplex=on)
(pool=on)
(tick=2)(in=10)(out=15)”

tnsname
(service_name=test)(server=shared)

rman requies dedicatied connection

Connectoin Manager
Router
connects sent to next address
firwall
filtering of connection request

connecion concentration
oralce shred servers

Access control

Multiple protocol support
multiple network Integration

2 process
cmgw
gateway process
listens from client connection request
cmadmin
administrative process

Connection concentration
funneling or multiplexing
saves server resources
multiple connection between process

Dispatchers= (multiplex=on)

Multiple protocol support
communicate between incompatible
network and protocols

<tnsname>=
(description =
(source_route= yes) sprohibits user of load balacing and failover
(Address_LIST =
(Address = (Protocol =spx) (service =cman))
(Address = (Protocol =tcp) (host=hostname )(port=no)

network/admin/cman.ora

cman=
(Address_list =
(Address=(protocol=tcp)(host=hostname)(prot=no))
(Address=(protocol=tcps)(host=hostname)(prot=no))
(Address=(protocol=spx)(host=hostname)(prot=no))
)

cman_admin

cman_admin=
(Address=protocol=tcp)(host=hostname)(prot=1830))

cman_rules

cman_rules =
(rule_list =
(rule = (src=hostname)(dst=hostname)(srv=sid)(act=accept|reject))

(rule = (src=hostname)(dst=hostname)(srv=sid)(act=accept|reject))

)

cman_profile
cman_profile=(parameter_list =(…))

netservices and utilities
tnsping
trcsess
trcroute
lnnrctl
namectl
cmctl
oracle enterprise manger
agentctl
dbsnmp

oracle net services Advanced Features
Transparent application failover
runtime failove option

desc v$session
username
failover_type
failover_method
failed_over

taf parameters
backup
failover tns name
delay
connection attempt delay

method
basic
preconnect
minimum failover time
type
non
session
reconnects
select
recovers selects

retries
failover connection attempts

configuration taf
taf can failover to another listener
transparent and seamless
connection /session uninterrupted
not the default
default is no select recovery
overhead
tnsnames.ora
failover_mode parameter

primary=
(description_list =
(failover=true) (load_balance=yes)
(description =
(address=
(protocol =tcp)(host =hotname)(port=1521))
(connect_data = (service_name=sid)(server=dedicated)
(failover_mode = (type=select)(method=preconnect)(backup=failover)
(retries=20)(delay=30))))
(description=
(Address =
(protocol=tcp)(host=hostname)(port=1522))
(connect_data =(service_name=sid) (server=dedicated))))

failover=
(description=
(Address =
(protocol=tcp)(host=hostname)(port=1522))
(connect_data =(service_name=sid) (server=dedicated))))

external procedures(c,c++,java)
heterogeneous services
other relational databases
transparent gateways
databaselinks

sybase
ingres
informx
sql server
db2

Oracle net services metadata
Performance view

shared servers
v$shared_server
v$queue
v$shared_server_monitor

dispatchers
v$dispatcher
v$queue
v$dispatcher_rate

virtual circuits
v$circuit

===========================
Backup and recovery

backup
restroation (file copy)
recovery

why backup
protect database
system failure
partial
catastrophic(entrie)

reconstruction
recovery
complete
partial
scn
point in time

thing to rember
recover as as backup
atleat

local versus physical
logical simpler
incomplete
can be slow
physical more complex
restore and recovery
much faster
complete

thing to consider
split to separate disk
datafiles
redo logs
controlfile
archive logs

redo logs
select * from v$log
select name,open_mode from v$database;
select * from v$logfile;

alter database add logfile member ‘c:\oracle\oradata\test\redo01b’ to group 1
alter database add logfile member ‘c:\oracle\oradata\test\redo02b’ to group 2
alter database add logfile member ‘c:\oracle\oradata\test\redo03b’ to group 3
alter database add logfile member ‘c:\oracle\oradata\test\redo04b’ to group 4
alter database add logfile member ‘c:\oracle\oradata\test\redo05b’ to group 5

shutdown immediate
startup mount pfile=’c:\oracle\admin\prod\initprod.ora’;
creat pfile=’ ‘ from file ‘ ‘;
shutdown immediate
startup

alter system switch logfile;

control file
shutdownd database
copy 2 control file
edit parameter file
add 2 ctrl file
startup mount pfile=’c:\oracle\admin\prod\initprod.ora’;
creat pfile=’ ‘ from file ‘ ‘;
shutdown immediate
startup

archive log
select name,value from v$parameter order=1;

log_archive_dest_1

multipex controlfiles
duplex redo logs
unrecoverable /nologging
ricky
backup prudent
Automate backup and recovery
procedures
scripting
tools
rman
scheduling
rotate tapes

primary backup
on database server
rapid restore
minor error
secondary backup
tape
cdrom
disk elsewhere
use stanby,Replication or clustering

imporat of backup and recovery
potential data loss
minor
castrophic

backup and recovery
planning
potential restore and recovery
strategy
backup
cater for fast recovery

points of failure
media failure
fare

user/appliatoin error
most lekely

oracle failure
session termination
database shutdown

alter system enable restricted session;
sid,serial#,username v$session
alter system kill session “11,25″;

how bckup and recovey works

check point
alter system checkpoint;
flush dirty block to data buffer cache to datafile

when backup to online alter checkpoing

The controlfile
contis set of pointer to datfile archivelogs datafiles

datafile header will contain scns
and control file with contail scn for each data file

if scn datfile is behind the control file is not uptodate with
archivelog and redologs and updates using scn form archive logs and redo logs
redo contain the last scn and matche the scn and redo logs

older copies of redolog is archivelogs

SCN (System change number)
is changed happend in database has sequencle number
each datafile in its header contains scn to it self
control file contains scn reference to each datafile

if datafile scn is behind the control file
then process of recovey goes to redolog file and archive logs
and replythem with datafile headr and scn

Basic archive configuration parameters

log_archive_dest_1= location=”c:\oracle\oradata\vtc\archive’
log_archive_format=%t_%s.dbf (t= threadno s for sequence)
log_archive_start=true
remote_archive_enable=true
log_parallelism=1

archive_lag_target
log_archive_trace
log_parallelism (datamining)
fast_start_mttr_target

exmine database archive status
archive log list;

switching off
log_archive_start=false
and recreate the binary file

shutdown immediate
connect sys/password$test as sysdba
startup mount pfile=”
create spfile=
alter databse archivelog;
startup

shutdown immediate
startup mount
alter databale archivelog; ==in mounted mode
shutdown immediate
statup

alter database noarchivelog

alter system switch logfile;== mounted mode

v$arvhivedlog

multiple archvie processes
log_archive_max_processes=2

v$archive_processes;

alter system set log_archive_max_processes=3;

Multiple Archive Destination
log_archive_dest
log_archive_duplex_dest
log_archive_min_succeed_dest
log_archive_dest_{1..10}
log_archive_dest_state_{1..10}
standby_archive_dest

Standby Archiving
primary database
standby database
multiple standby database
remote database

primary database parameters

log_archive_deskt_1=’location=c:\oracle\oradata\prim\archive Mandatory reopen=30′
log_archive_dest_state_1=enable
log_archive_dest2=
‘service=stby lgwr sync=parallel affirm’
log_archive_dest_state2=enable
log_archive_dest3=
‘service=failover arch affirm’
log_archive_dest_state_3=enable
log_archive_min_succeed_dest=3
remote_archive_enable=true

standby_archive_dest=
‘e:\oracle\oradata\sid\archive’
log_archive_dest_1=
‘location=e:\oracle\oradata\sid\archive’
remote_archive_enable=true

export import
buffer
(read process of reading and wriding)
10240

exp system/system files=c:\a.exp log=c:\a.log full=y buffer=1024 direct=y
imp system/system files=c:\a.exp log=c:\aa.log full=y buffer=1024

exp employees/employees@test file=c:\test.exp log=c:\a.log buffer=10240 direct=y consistent=y

create tablespace data datafile ‘c:\oracle\oradata\prod\data01.dbf’ size 10M autoextend on;
create tablespace objects datafile ‘c:\oracle\oradata\prod\objects01.dbf’ size 10M autoextend on;

select tablespace_name from dba_tablespaces;
drop user employees cascade;

create user employee identified by employees
default tablespace data
temporary tablespace temp
quota unlimited on data
quota unlimited on indx
quota unlimited on objects
quota unlimited on temp;

grant connect,resource to employees;
grant unlimited tablespace to employees;
grant query rewrite to employees;

imp system/system@vtc file=c:\tmp\employees.exp
log=c:\a.log fromuser=employees touser=employees buffer=10240 commit=y

exp system/system@test owner=(books,abc,xy) file=c:\a.dmp
log=c:\a.log buffer=10240 direct=y consistent=y

create 2 user
book and abc

imp system/system@vtc file=c:\tmp\employees.exp
log=c:\a.log fromuser=books touser=books buffer=10240 commit=y

create user booking
imp system/system@vtc file=c:\tmp\employees.exp
log=c:\a.log fromuser=books touser=booking buffer=1024. commit=y

physical backup , restore and recovery
at operating system level
shutdown database
copy
datafiles
controlfiles
archive logs

not required
redo logs

optional
configuration files
password files

restart database

connect sys/password@test As sysdba
shutdown immediate
copy datafile , controlfiles, redo logs and archive logs
no need to copy temp
startup

can also copy parameters, password file and all network configuration

hot backup
data files are copied individualy
control file are copyed using alter database
no need to copy redologs

connect sys/system@test@ sysdba
alter tablespace data begin backup
$copy c:\oracle\oradata\test\data01.dbf c:\tmp
alter tablespace data end backup
alter database backup control file to ‘c:\oracle\data\test\control01.bak’ reuse
alter database backup controlfile to trace

copy archive logs
can also copy parameter password file and all network configuration

restore
dbv help=y
dbc file=c:\oracle\oradata\test\data01.bak blocksize=8192 logfile=c:\a.log

try to find the below error
total pages failing
total pages marked corrupt
total pages infux

#!/bin/sh
USAGE=”$0: incorrect argument, Use $0 <sid>”

if [ `whoami` !- 'oracle' ]; then
echo Aborted -u `whoami` is incorrect, must be user oracle
exit 1
elif [ -z "$1" ]; then
echo “$usage”
exit 1

else
echo executing .. perl beforRestore.pl $ORACLE_BASE/oradata/$1 $ORACLE_HOME
perl beforeRestore.pl $ORACLE_BASE/oradata/$1 $ORACLE_HOME
perl beforeRestorelOGS.pl $ORACLE_BASE/oradata/$1 $ORACLE_HOME
fi

beforeRestore.pl
$path = shift;
$ORACLE_HOME = shift;

system(“ls -a $path/*.dbf > ./list”);
open(IN,”./list”);

while(<IN>)
{
chomp($_);
@name = split(“\/”,$_);
$names = $name;
$filename = $name[$name-1]; chomp($filename);
print “$ORACLE_HOME/bin/dbv file=$_ blocksize=8192 logile=./log/$filename.log\n”;
system (“$ORACLE_HOME/bin/dbv file=$_ blocksize=8192 logile=./log/$filename.log”);
}
close(IN);

beforeRestoreLogs.pl

$path = shift;
$ORACLE_HOME = shift;

system(“ls -a $path/*.dbf > ./list”);
open(IN,”./list”);

while(<IN>)
{

chomp($_);
@name = split(“\/”,$_);
$names = $name;
$filename = $name[$name-1]; chomp($filename);

if (open(file,”./log/$filename.log”) == 1)
{
while(<file>
{

chomp($_);
if ($_ =~ /^Total Pages Failing.*: (\d*)$/i { if (int($1) != 0) { print “$filename, $_\n”; } }
if ($_ =~ /^Total Pages Marked Corrupt.*: (\d*)$/i { if(int($) != 0){ print “$filename, $_\n”; } }
if ($_ =~ /^Total Pages Influx.*: (\d*)$/i { if(int($) !=0 ){ print “$filename, $_\n”; } }
}
close(file);
}
}
close(IN);

Restore
in cold physical database (database snapshot)
conect sys/password@test as sysdba
shutdown immediate
restore and copy the datafiles,controlfile,archivelogs back in os
startup

in restore hot backup

alter database datafile ‘c:\oracle\oradata\test\data01′ offline;
alter database data offile
dba_tablespaces

to restore simply copy files back and recover usin(archive and datafiles)
to take effet

–alter database recover database;
–alter database recover tablespace data
alter database recover datafile ‘c:\oracle\oradata\test\data01.dbf’;
alter database datafile ‘c:\oracle\oradata\test\data01′ online;
alter tablespace data online

– partial recovery recovers parts of a database such as a single datafile or tablespace or database
when requies recovery will be detected by the controlfile besed on scn no
then the missing redo log entries are re=executed in what ever datafiles and updated from archivelog
both redo log file and archive log files will be used if so required…

Read only Tablespace cannot be changed
never changed
simply copy
static tables object

incomplete Recovery (recover till centrain time)
time based
cancel based
changebased
rman
log sequence number

recover database
[until
{time date
|change scn
|cancel }
];

Automation and scability

what is rman
utility
backup
recovery
commandline
oracle entriprise manager

Advantage
complexity management
fewer human errors
scabilitity (incremental backup)
reliability (fully tested)
incremental
faster

Repository and catalog
repository is used store the record of backup
catlog add one piece of guddies like scripts
repository resign in ,controlfile on target database

control file
on target database
backup only
repository
no scripting
limited automation
risck of loss
sperate
catalog and repository
schema
database

catalog and repository
repository goes into controlfile
it store all the backup of record
it also has catlog stored in seperate schema database or exta database server

catlog allow the complete record of all back to
ability to stop scriptring and execute automatically
within rman and recovery manager
manage multiple database from single recovery manager repository

The recovery catalog
store in seperate database
backup, records with a controlfile
catlog basically includes both the history of all
backup sessions references backup plus genera
meta data views and perforamtion inforamtion into that backup
plus the scripts which can be automated

The Recovery Catalog
all backups
references
dates
set membership
Strogae
control file
Rman repository
any databse
independent database
auto mation
scription
cannot backup itself

Rman Architecture
rman executed from os
need deticated connection
rman has seperate database

and can maintain standby and duplicaton

waht is a channel
device or connect to device to allow copying or bakupand recovry
connection to the device to do backup and recovery

allocate channel to the process

allocating a channel
run
{
allocate channel ch1 type disc
sql ‘alter system archive log current’;
backup database filesperset2;
format $ORACLE_DBF/backup/database/%U’;
tag=’database’;
release channel ch1;
allocate channel ch1 type disk;
backup current control file
tag=’post daabase controlfile’;
release channel ch1;
}

automated in 10g

Creating a repository

Create a database
The rman tablespace
the rman user
privileges
the rman catlog

new database
rman
remove exta option
no archivemode
(datafile) undotbs01.dbf filezie=20

create the rman tabalespace
conncect sys/password@rman as sysdba;
create tablespace rcvcat datafile ‘c:\oracle\oradata\rman\rcvcat01.dbf’
size 10M autoextend on;

create user rman identified by rman
defualt tablespace rcvcat
temporary tablespace temp
quota unlimited on rcvcat

grant sysdba,sysoper,dba,recovery_catlog_owner,
connect,resource, select any table to rman;

select username,default_tablespace from dba_users;
select tablespace_name,file_name from dba_data_files;

from shell
rman
connect target
connect catalog rman/rman@rman
connect target system/system@vtc
rman catalog rman/tmp@rman @createCatalog.sql

form the shell command line
rman target=”sysem/system@vtc” nocatalog
rman target=”sysem/system@vtc” catalog=”rman/rman@rman”
rman target / nocatalog
rman target / catalog=”rman/rman@rman”

rman target / nocatalog rman/rman@rman

can connect 3 database at onces

registering database to repository

dbmust be started
rman target=”system/system@test” catalog=”rman/rman@rman”
register database;

rman target=”system/system@test1″ catalog=”rman/rman@rman”
register database;

rman target=”system/system@oemrep” catalog=”rman/rman@rman”
register database;

unregistering database
connect rman/rman@rman;
select * from db;
connect sys/password@test as sysdba
select dbid,name from v$database;
execute dbms_rcvcat.unregisterdatabase (DB_KEY,DB_ID);

rman target=”system/system@vtc” catalog=”rman/rman@rman”

viewing the repository
list command
list { [expired] backup [by file | summary ] | [expired] copy | archivelog all};

list backup
list backup summary
list expired copy;
list archivelog all;

report need backup
report unrecoverable database;

crosscheck { backup | copy };

connect sys/password@vtc as sysdba
select dbid,name,open_mod from v$database;

connect rman/rman@rman;
select * from db;
select * from rc_database;

Backup Sets
set of file
within a backup
allows for restaring

backup {databse filesperset=2
archivelog all filesperset=5

up to 2 datafiles per backup set
up to 5 archive log files per backupset

backup maxsetsize=10M archivelog ALL;

types of backups
Unit backups
controlfiles
datafiles
tablepaces
archivelogs
binary parameters file
Database Backups
Incremental

Unit backup(pieces backup)
rman target=”system/system@test” catlog=”rman/rman@rman”

controlfiles
backup current controlfile;
backup current controlfile tab ‘one’;
list backup of controlfile;

rman target=”system/system@master” catlog=”rman/rman@rman”
backup current controlfile;

rman target=”system/system@oemrep” catlog=”rman/rman@rman”
backup current controlfile;

rman target=”system/system@test” catlog=”rman/rman@rman”
–datafiles
–connect sys/password@test as sysdba;
select file_id,tablespace_name,filename from dba_data_files;

rman target=”system/system@test” catlog=”rman/rman@rman”
backup datafile 1,2,5,8,10,11 filesperset 2;
list backup of datafile 10;

connect sys/password@master as sysdba;
select file_id,tablespace_name,filename from dba_data_files;

rman target=”system/system@master” catlog=”rman/rman@rman”
backup datafile 1,2,5,8,10,11 filesperset 3;

connect sys/password@oem as sysdba;
select file_id,tablespace_name,filename from dba_data_files;

rman target=”system/system@oem” catlog=”rman/rman@rman”
backup datafile 10;

rman target=”system/system@test” catlog=”rman/rman@rman”

connect sys/password@test as sysdba;
select tablespace_name from dba_tablespaces;

backup filesperset=2 tablespace system,indx,users,data,objects;
list backup of tablespaces data;
backup filesperset=2 tablespace system,indx,users,data,objects include current controlfile;
backup tablespace data include current controlfile;
list backup of tablespace data;
list backup of controlfile;

connect sys/password@master as sysdba;
select tablespace_name from dba_tablespaces;
rman target=”system/system@master” catlog=”rman/rman@rman”
backup filesperset=2 tablespace indx,users,data,streams;

connect sys/password@oemrep as sysdba;
rman target=”system/system@oemrep” catlog=”rman/rman@rman”
backup filesperset=2 tablespace system,oem_repository;

rman target=”system/system@test” catlog=”rman/rman@rman”
backup archivelog all
–delete all copies on disk
–backup archivelog [all delete all input ];
–backup archvielog [ from time 'sysdate-1 until time 'sysdate' ];
list backup of archivelog all;

–oemrep is not archived
–connect sys/password@oemrep as sysdba;
–shutdown immediate
–startup mount;
–alter database archivelog;
–mkdir
–copy archive parameters using alter system

–rman target=”system/system@oemrep” catlog=”rman/rman@rman”
backup archivelog all;

–rman target=”system/system@master” catlog=”rman/rman@rman”
backup archivelog all;

backup binary parameter file
rman target=”system/system@test” catlog=”rman/rman@rman”
backup spfile;
rman target=”system/system@oemrep” catlog=”rman/rman@rman”
backup spfile;
rman target=”system/system@master” catlog=”rman/rman@rman”
backup spfile;

–rman target=”system/system@test” catlog=”rman/rman@rman”
–control file and spfile automatically included with backup database
backup database;
backup database format ‘c:\tmp\%U’ tag=’whole database’;
–show files in c:\tmp directory

validation prior to backup (like dbverify, no backups created just vrication
backup validate database

–alter system switch logfile;
–backup database plus archivelog;
–backup validate database archivelog all;
–list backup of database;
–list backup of database summary;

–restarting a backup
backup not backed up since ‘SYSDATE-1′ DATABASE PLUS archivelog;

Incremental Backups
writes only changed blocks
reads all of datafile
function in layers
levels
levels 0 base level
automatic if none exits
basis of all subsequent backups
level1 backup
all blocks changed after last level 1
level2 backup
all blocks changed after last level 2

level 1 over writes 1 level2 overwirtes level2
Monly: level 0
weeky level 1
daily: level 2

Differentail and cumulative

differential
since most current level
cumulative
since most current level -1

–rman target=”system/system@test” catlog=”rman/rman@rman”
monthly
backup incremental level=0 database;

weekly
backup incremental level=1 tabalespace system,indx,users,data,objects tag=’weekly’;

–daily
backup incremental level=2 tablespace user,data tag=’daily’;

list backup of database;

–weekly
backup incremental level=2 cumulative database;

Restore and Recovery
Unit (partial) recovery
Incomplete Recovery
UNTIL TIME
UNTIL Sequence
validation

Option
Restore
to Difference locations
enven a different host
individual corrupted blocks
create
duplicate databases
standby dtabases

–rman target=”system/system@test” catlog=”rman/rman@rman”

–connected to target
shutdown immediate;
startup mount;

–veryfy target database mode
–connect sys/password@test as sysdba;
select name, open_mode from v$database;

–rman target=”system/system@test” catlog=”rman/rman@rman”
restore database;
recover database;
alter database open;

–verify target database mode
–connect sys/password@vtc as sysdba;
select name,open_mode from V$database;

–partial restoration and recovery
–connect sys/password@vtc as sysdba;
alter tablespace data offline immediate;
–rman target=”system/system@test” catlog=”rman/rman@rman”
restore tablespace data;
recover tablespace data;

–connect sys/password@test as sysdba;
alter tablespace data online;

incomplete recovery

–connect to target
shutdown immediate;
startup mount;
–rman target=”system/system@test” catlog=”rman/rman@rman”
restore database until time ‘sysdate’;
recover database until time ‘sysdate’;

–connected to target
alter database open resetlogs;

–validate backup without restore or recovery
restore database validate;

Scripts and Rman

must use catalog
nocatlog
using controlfile

scripts
create
replace
delete
execute

–rman target=”system/system@test” catlog=”rman/rman@rman”
create script monthly
{
backup database plus archivelog;
delete obsolete;
}
delete script ‘monthly’;

create script monthly
{
backup incremental level=0 database plus archivelog;
delete obsolete;
}

create script weekly
{
backup incremental level=1 tablespace system,indx,users,data,objects;
delete obsolete;
}

create script daily
{
backup incremental level=2 tablespace user,data;
delete obsolete;
}

run { execute script daily; }

replace script daily
{
backup incremental level=2 tablespace users,data,objects;
delete obsolete;
}
run{ execute script daily; }

deleting rman backups
list backup of database archivelog all

BP KEY: 752

–rman target=”system/system@test” catlog=”rman/rman@rman”
report obsolete;
delete obsolete;

crosscheck backup
delete expired;
delete archivelog all;

during backup
backup archivelog all delete input;
list copy;

allocate channel for maintenance device type disk;
list backup
delete backuppiece 752;
delete backuppiece 768,778,554,214;

list backup of database archivelog all;

–the repository should now be emply of all backups
connect sys/password@rman as sysdba;
drop user rman cascade;
drop tablespace rvcat including contents;

–show file in c:\tmp directory dissapered!

Continue Reading

Oracle Userfull scripts

Posted on 03. Mar, 2008 by sabin.

http://www.materialdreams.com/oracle/

http://www.orafaq.com/

http://www.orafaq.com/scripts/

http://www.idevelopment.info/data/Oracle/DBA_tips/Sun_Solaris/SUNSOLARIS_5.shtml

http://www.dbasupport.com/oracle/scripts/

Tracing the Sessions(s) of a Given User

In a case where you cannot (because you don’t have enough time, for example) query V$SESSION to initiate a trace for the session, and you have to trace a “fast” user session, (for example, initiated by clicking on a button on the GUI of an application), this code traces the session(s) of a given user by using a database “on logon” trigger.

CREATE OR REPLACE TRIGGER ON_LOGON_SCOTT
AFTER LOGON ON DATABASE
WHEN ( USER = 'SCOTT' )
BEGIN
execute immediate 'alter session set events ''10046 trace name context forever, level 12''';
EXCEPTION
WHEN OTHERS THEN
NULL;
END;

Remarks:

1) The “exception” block is of utmost importance to avoid trouble should something go wrong with the trigger.
2) The trigger can contain more conditions (for example: if sysdate between XXX and YYY)
3) Once the trigger is enabled, all new sessions of the user will be traced. To suspend this behavior, perform: ALTER TRIGGER ON_LOGON_SCOTT DISABLE;
4) When not necessary anymore, drop the trigger instead of keeping it “disabled” (somebody might re-enable it by mistake): DROP TRIGGER ON_LOGON_SCOTT;

==============================================

Tablespace Free (and more) Report

This script can be run on Oracle8i, Oracle9i and Oracle 10g databases to get a report/graph on tablespace free information, somewhat similar to the report from Oracle Enterprise Manager. The report provides a look at all the tablespaces in a database with information like “number of files in the TS”, “Size(MB)”, “Free(MB)”, “Tablespace extensible to”, and a graph of space usage. The output is sorted by “% Free”, which shows the tablespaces that need immediate attention at the top.

column "File Count" format 999999
column "Size(MB)" format 999,999,999.99
column "Free(MB)" format 999,999,999.99
column "Used(MB)" format 999,999,999.99
column "Max Ext(MB)" format 999,999,999.99
column "% Free" format 999.99
column "% Free Ext" format 999.99
column "Graph" format a11
column tablespace_name format a20

SELECT ts.tablespace_name,

"File Count",

TRUNC("SIZE(MB)", 2) "Size(MB)",

TRUNC(fr."FREE(MB)", 2) "Free(MB)",

TRUNC("SIZE(MB)" - "FREE(MB)", 2) "Used(MB)",

df."MAX_EXT" "Max Ext(MB)",

(fr."FREE(MB)" / df."SIZE(MB)") * 100 "% Free",

RPAD('*', TRUNC(CEIL((fr."FREE(MB)" / df."SIZE(MB)") * 100)/10), '*') "Graph"

-- ,((DECODE(df."MAX_EXT", 0, df."SIZE(MB)", df."MAX_EXT") - fr."FREE(MB)") / DECODE(df."MAX_EXT", 0, df."SIZE(MB)", df."MAX_EXT")) * 100 "% Free Ext"

FROM (SELECT tablespace_name,

SUM(bytes) / (1024 * 1024) "FREE(MB)"

FROM dba_free_space

GROUP BY tablespace_name) fr,

(SELECT tablespace_name,

SUM(bytes) / (1024 * 1024) "SIZE(MB)",

COUNT(*) "File Count",

SUM(maxbytes) / (1024 * 1024) "MAX_EXT"

FROM dba_data_files

GROUP BY tablespace_name) df,

(SELECT tablespace_name

FROM dba_tablespaces) ts

WHERE fr.tablespace_name = df.tablespace_name (+)

AND fr.tablespace_name = ts.tablespace_name (+)

ORDER BY "% Free"

/

=====================================================

Track and Monitor Resources

Running this query will produce a list of database statements and objects that are using the most resources.

Note: Execute as SYS user.


select V1.sid, V1.serial#, V2.USERNAME, V2.OSUSER, V1.opname, to_char(V1.start_t
ime, 'HH24:MI:SS') AS Started, (V1.SOFAR/V1.TOTALWORK)*100 AS Pct_completed
FROM V$SESSION_LONGOPS V1, V$SESSION V2
WHERE V1.SID= V2.SID AND V1.SERIAL#=V2.SERIAL#
AND (SOFAR/TOTALWORK)*100 < 100
AND TOTALWORK > 0

=====================================================

Get CPU Attribution

This tip is for use in Oracle Database 10g. The following query will allow you to see the CPU attribution of the first level plan and the CPU attribution of the subplans used by this plan. (The query assumes that your first level plan is named “PLAN…” and your subplan is named “SPLAN…”.) Note that Oracle also provides the “View Resource Plan” screen in Oracle Enterprise Manager Grid Control where you can see the CPU attribution that you specified for a plan.

set lines 100
break on "PLAN " skip 1
select substr(substr(SYS_CONNECT_BY_PATH(plan, '/'),
2,
instr(substr(SYS_CONNECT_BY_PATH(plan, '/'),2)||'/','/')-1),1,20) "PLAN ",
decode(level,1,group_or_subplan,'..'||group_or_subplan) "GROUPE/SUBPLAN",
decode(level,1,to_char(cpu_p1,'9999'),' ..') "CPU_1",
decode(level,1,to_char(cpu_p2,'9999'),' ..') "CPU_2",
decode(level,1,to_char(cpu_p3,'9999'),' ..') "CPU_3",
decode(level,1,' ',to_char(cpu_p1,'999999999999')) "SUBPLAN_CPU_1"
from dba_rsrc_plan_directives
start with plan like 'PLAN_%'
connect by prior group_or_subplan = plan
order by "PLAN ", decode(level,1,group_or_subplan,plan), level, "GROUPE/SUBPLAN";

==================================================

Number to Word

set echo on
set feedback on

/***************************************************************************/* */
/* Procedure: NumberToWords */
/* Description: This package provides a function NumberToWords converting numbers to their */
/* English equivalent and returns it as a string. */
/* */
/* Version: 1.0.0 */
/* */
/* Required: Oracle Server Version 7.3 or higher. */
/* */
/* Example: */
/* */
/* SELECT NumberToWords.NumberToWords(1234567890) FROM DUAL; */
/* */
/* Written by: Material Dreams */
/* EMail: info@materialdreams.com */
/* WWW: http://www.materialdreams.com/oracle */
/* */
/* License: This script can be freely distributed as long as this header will not be removed and */
/* improvements and changes to this script will be reported to the author. */
/* */
/* Copyright (c) 1995-2004 by Material Dreams. All Rights Reserved. */
/* */
/**********************************************************************************************************/

Convert Numbers into Words

This query converts numbers into their text equivalents.

select to_char(to_date(873,'J'), 'JSP') as converted_form from dual;

CONVERTED_FORM
---------------------------
EIGHT HUNDRED SEVENTY-THREE

J represents the Julian format. When the to_char function is applied to the result of to_date, it spells (SP) the word for the number passed to to_date.

/* Create the package header */
CREATE OR REPLACE
PACKAGE NumberToWords IS
FUNCTION NumberToWords(theValue IN NUMBER) RETURN VARCHAR2;
END NumberToWords;
/

/* Create the package body */
CREATE OR REPLACE
PACKAGE BODY NumberToWords IS

TYPE NXR IS RECORD (Name VARCHAR2(60), Value INTEGER);
TYPE NXT IS TABLE OF NXR INDEX BY BINARY_INTEGER;
TYPE DMT IS TABLE OF VARCHAR2(60) INDEX BY BINARY_INTEGER;

numarr NXT;
denom DMT;

FUNCTION CVT2(theValue IN INTEGER) RETURN VARCHAR2;
FUNCTION CVT3(theValue IN INTEGER) RETURN VARCHAR2;

FUNCTION NumberToWords(theValue IN NUMBER) RETURN VARCHAR2
IS
val NUMBER := theValue;
tri INTEGER := 0; — last tree digits
place INTEGER := 0; — which power of 10 we are on
neg BOOLEAN := FALSE; — sign holder
temp VARCHAR2(255);
word VARCHAR2(255);
phrase VARCHAR2(255);
BEGIN
– check for 0
IF (val = 0) THEN
word := ‘zero’;
RETURN word;
END IF;

– check for negative int
IF (val < 0) THEN
neg := TRUE;
val := -val;
END IF;

– what we do now is break it up into sets of three, and add the appropriate denominations to each
WHILE (val > 0) LOOP
phrase := NULL;
tri := MOD(val, 1000); — last tree digits
val := FLOOR(val / 1000); — base 10 shift by 3
IF (tri > 0) THEN
phrase := phrase || CVT3(tri) || ‘ ‘;
END IF;
IF ((place > 0) AND (tri > 0)) THEN
phrase := phrase || denom(place+1);
END IF;
place := place + 1;

– got the phrase, now put in the string
temp := word;
IF ((val > 0) AND (tri > 0)) THEN
word := ‘, ‘ || phrase;
ELSE
word := phrase;
END IF;
word := word || temp;
END LOOP;

– remember that minus sign
IF (neg) THEN
word := ‘negative ‘ || word;
END IF;

RETURN word;
END NumberToWords;

FUNCTION CVT2(theValue IN INTEGER) RETURN VARCHAR2
IS
v NUMBER := theValue;
i PLS_INTEGER := 0;
s VARCHAR2(80);
BEGIN
i := 1;
WHILE (numarr(i).Value <= v) LOOP
i := i + 1;
END LOOP;

s := numarr(i-1).Name;
v := v – numarr(i-1).Value;

IF (v > 0) THEN
s := s || ‘-’ || numarr(v+1).Name;
END IF;

RETURN s;
END CVT2;

FUNCTION CVT3(theValue IN INTEGER) RETURN VARCHAR2
IS
v NUMBER := theValue;
r INTEGER;
m INTEGER;
s VARCHAR2(80);
BEGIN
m := MOD(v, 100);
r := FLOOR(v / 100);

IF (r > 0) THEN
s := s || numarr(r+1).Name;
s := s || ‘ hundred’;
IF (m > 0) THEN
s := s || ‘ ‘;
END IF;
END IF;

IF (m > 0) THEN
s := s || CVT2(m);
END IF;

RETURN s;
END CVT3;

BEGIN
– initialize the arrays
numarr(01).Name := ‘zero’; numarr(02).Name := ‘one’; numarr(03).Name := ‘two’; numarr(04).Name := ‘three’; numarr(05).Name := ‘four’; numarr(06).Name := ‘five’; numarr(07).Name := ‘six’; numarr(08).Name := ‘seven’; numarr(09).Name := ‘eight’; numarr(10).Name := ‘nine’; numarr(11).Name := ‘ten’; numarr(12).Name := ‘eleven’; numarr(13).Name := ‘twelve’; numarr(14).Name := ‘thirteen’; numarr(15).Name := ‘fourteen’; numarr(16).Name := ‘fifteen’; numarr(17).Name := ‘sixteen’; numarr(18).Name := ‘seventeen’; numarr(19).Name := ‘eighteen’; numarr(20).Name := ‘nineteen’; numarr(21).Name := ‘twenty’; numarr(22).Name := ‘thirty’; numarr(23).Name := ‘forty’; numarr(24).Name := ‘fifty’; numarr(25).Name := ‘sixty’; numarr(26).Name := ‘seventy’; numarr(27).Name := ‘eighty’; numarr(28).Name := ‘ninety’; numarr(29).Name := ”; numarr(1).Value := 0;
numarr(2).Value := 1;
numarr(3).Value := 2;
numarr(4).Value := 3;
numarr(5).Value := 4;
numarr(6).Value := 5;
numarr(7).Value := 6;
numarr(8).Value := 7;
numarr(9).Value := 8;
numarr(10).Value := 9;
numarr(11).Value := 10;
numarr(12).Value := 11;
numarr(13).Value := 12;
numarr(14).Value := 13;
numarr(15).Value := 14;
numarr(16).Value := 15;
numarr(17).Value := 16;
numarr(18).Value := 17;
numarr(19).Value := 18;
numarr(20).Value := 19;
numarr(21).Value := 20;
numarr(22).Value := 30;
numarr(23).Value := 40;
numarr(24).Value := 50;
numarr(25).Value := 60;
numarr(26).Value := 70;
numarr(27).Value := 80;
numarr(28).Value := 90;
numarr(29).Value := 999;

denom(01) := ”;
denom(02) := ‘thousand’;
denom(03) := ‘million’;
denom(04) := ‘billion’;
denom(05) := ‘trillion’;
denom(06) := ‘quadrillion’;
denom(07) := ‘quintillion’;
denom(08) := ‘sextillion’;
denom(10) := ‘septillion’;
denom(11) := ‘octillion’;
denom(12) := ‘nonillion’;
denom(13) := ‘decillion’;
denom(14) := ‘undecillion’;
denom(15) := ‘duodecillion’;
denom(16) := ‘tredecillion’;
denom(17) := ‘quattuordecillion’;
denom(18) := ‘sexdecillion’;
denom(19) := ‘septendecillion’;
denom(20) := ‘octodecillion’;
denom(21) := ‘novemdecillion’;
denom(22) := ‘vigintillion’;

END NumberToWords;
/

/* Example */
SELECT NumberToWords.NumberToWords(1234567890) FROM DUAL;
/
=====================================================

User Logon Validation Trigger

This trigger verifies whether a user logging into the database is (pre)authorized to connect to the database using the approved client machine, client software, etc.

-- connect as sys/*****

CREATE TABLE authorize_users_tab(
username VARCHAR2(30),
osuser VARCHAR2(30),
program VARCHAR2(64),
machine VARCHAR2(64)
);

ALTER TABLE authorize_users_tab
ADD CONSTRAINT user_prog_mach_uk
UNIQUE (username,osuser,program,machine);

-- Insert appropiate values into this table, so only the entered
-- users will be permitted to connect to that database, query
-- V$SESSION for correct info, data entered into the table are
-- case sensitive.

insert into authorize_users_tab values ('SCOTT','DOMAIN\OSUSER','SQLPLUSW.EXE','DOMAIN\MACHINE');
insert into authorize_users_tab values ('TESTUSER','DOMAIN\OSUSER','SQLPLUSW.EXE','DOMAIN\MACHINE');
commit;

CREATE OR REPLACE TRIGGER authorize_users_trig
AFTER LOGON ON DATABASE

-- Description: This trigger helps database administrators to
-- control users logging into the database using various client
-- tools and machines. List of USERNAME, OSUSER, PROGRAM and
-- MACHINE entered in table AUTHORIZE_USERS_TAB will only be
-- permitted to login into the database.
-- Ref Oracle Bug No.2628258 and Doc No.2628258.8 in Metalink for
-- using RTRIM(machine,CHR(0)) in the below code.
-- Caveat: When a user tries to connect via SQL*Plus and if the
-- trigger refuses connection, info about that session is shown
-- as INACTIVE in V$SESSION, unless that user closes the SQL*Plus
-- window/session.

DECLARE
p_count NUMBER(1);
BEGIN
SELECT COUNT(*) INTO p_count
FROM sys.authorize_users_tab
WHERE UPPER(username||osuser||program||RTRIM(machine,CHR(0)))
IN (
SELECT UPPER(username||osuser||program||RTRIM(machine,CHR(0)))
FROM v$session
! WHERE au dsid = USERENV('sessionid')
AND logon_time = (
SELECT MAX(logon_time)
FROM v$session
WHERE audsid = USERENV('sessionid')));
IF p_count = 0 THEN
RAISE_APPLICATION_ERROR(-20001, '---> Sorry, Access Denied <---');
END IF;
END ;
/

=====================================================

Collecting Percentage of CPU Used by Consumer Group

This tip is for people who use Oracle Resource Manager in Oracle Database 10g to manage CPU usage by consumer group. Oracle provides the V$RSRC_CONSUMER_GROUP view where you can see a CONSUMED_CPU_TIME column that contains the cumulative amount of CPU time consumed by all sessions in the consumer group. This column is cumulative, however, so it does not tell you anything about a specific period of time. So you cannot use it to know which consumer group consumed the most CPU in the last 5 minutes. You cannot collect a history of the CPU used by each group for specific period of time either. So here is what you can do to get this information. First of all, you need to create a snapshot of the V$RSRC_CONSUMER_GROUP because you cannot use the “as of timestamp” clause on a V$ view. Refresh this snapshot every minute.

create materialized view MV_RSRC_CONSUMER_GROUP
refresh FORCE
start with sysdate
next sysdate + 1 / 1440
as
SELECT name, consumed_cpu_time from v$rsrc_consumer_group;

Then, to get the %CPU used by each group in the last 5 minutes, use this query:

select b.name,
100 * (decode(sign(b.consumed_cpu_time - a.consumed_cpu_time),
-1, b.consumed_cpu_time,
b.consumed_cpu_time - a.consumed_cpu_time) /
decode(sign(c.cpu_tot_current - d.cpu_tot_before),
-1, c.cpu_tot_current,
c.cpu_tot_current - d.cpu_tot_before)) "CPU"
from MV_RSRC_CONSUMER_GROUP as of timestamp (systimestamp - interval '5' minute) a,
MV_RSRC_CONSUMER_GROUP b,
(select sum(consumed_cpu_time) "CPU_TOT_CURRENT"
from MV_RSRC_CONSUMER_GROUP) c,
(select sum(consumed_cpu_time) "CPU_TOT_BEFORE"
from MV_RSRC_CONSUMER_GROUP as of timestamp (systi! mestamp - interval '5' minute)) d
where b.name = a.name(+);

You can then use that query as a “User-Defined SQL Metrics” in Grid Control to collect a history of the CPU percentage used by each consumer group! You could modify the query easily to get the amount of CPU used instead of a percentage if you prefer. This is really useful if you want to monitor your consumer group and keep the history for a column that is cumulative in the V$RSRC_CONSUMER_GROUP. Just include it in the materialized view and define a “User-Defined SQL Metric” in Grid Control to keep historical data.=====================================================

export ORACLE_BASE=/<mountpoint>/oracle
export ORACLE_HOME=$ORACLE_BASE/product/10.0.2
exprot TNS_ADMIN=$ORACLE_HOME/network/admin
exprot ORACLE_SBIN=$ORACLE_HOME/sbin
export PATH
export host=`hostname`
export email=$`

USAGE=”$0: incorect arguments, Usage: $0<email>”
if [ -z "$email" ]; then
echo “$USAGE”
mailx -s “$USAGE” sabinshresth@hotmail.com</dev/null
exit 1
elif [ `whoami` != 'oracle ]; then
echo “$0 aborted user -where `whoami` is incorrect must be user oracle
mailx -s “$0 aborted – user -where `whoami` is incorrect must be user oracle” $email </dev/null
fi

echo “Executing $0 on $host”

err=”`tail -50 $ORACLE_ALERT/alert_$oracle_SIDlog | grep ORA-00600 |grep -v grep |wc -l`”
if [ $err -gt 0 ];
tail -50 $ORACLE_ALERT/alert_$oracle_SIDlog | grep ORA-00600 |grep -v grep> $ORACLE_SBIN/logs/ora600.log
sub=”Script $0 on $host detected ORA-0t00 for SID $ORACLE_SID”
echo $sub
mailx -s “$sub” $email < $ORACLE_SBIN/logs/ora600.log
exit 1
fi
exit 0

panic=95
screen=99
df -k | awk’{\
if (($1 !=”Filesystem”) && ($1! = “fd”) && ($1 != “/proc”)) \
{\
if($5 > scream) {print “scream !!! – Disk space on”,host,$1,”@”,%5 }\
else if ($5 > panic} { print “Panic – Disk space on”,host,$1,”@”,$5 }\
}\
}’ scream=$scream panic=$panic host=$host > /usr/local/sabin/log/diskspace.log

if [ -s /usr/local/sbin/log/diskspace.log ]; then
sub=”Script $0 on $host detected disk space limits exceeded !!!”
echo $sub
mail -s “$sub” $email</usr/local/sbin/logs/diskspace.log
exi 1
fi
exit 0

echo cleaning trace and transaton audit files for $1 upto 14 days ago
unalias rm
$find $ORACLE_BASE/admin/$1/bdump/*.trc -mtile +14 | xargs rm -f
$find $ORACLE_BASE/admin/$1/udump/*.trc -mtile +14 | xargs rm -f
$find $ORACLE_BASE/admin/$1/cdump/*.trc -mtile +14 | xargs rm -f
$find $ORACLE_BASE/rdbms/audit/*.aud -mtile +14 | xargs rm -f

alias rm ‘rm -i’

==================================
#!/bin/ksh
ALL_DATABASES=`cat /etc/oratab|grep -v “^#”|grep -v “N$”|cut -f1 -d: -s`
for DB in $ALL_DATABASES
do
unset TWO_TASK
export ORACLE_SID=$DB
export ORACLE_HOME=`grep “^${DB}:” /etc/oratab|cut -d: -f2 -s`
export PATH=$ORACLE_HOME/bin:$PATH
echo “—> Database $ORACLE_SID, using home $ORACLE_HOME”
sqlplus -s system/${DB}password @<<-EOF
select * from global_name;
exit;
EOF
done
——————–

sqlplus /NOLOG @conn.sql
# No messing with ps, no password leak, connect from witin conn.sql

or…

echo “Name : \c”
read Name
echo “Password : \c”
stty -echo
read Password
stty echo
echo ${Name}/${Password} | sqlplus

or…

USER=scott
PASSWORD=tiger
{ echo ${USER}/${PASSWORD}; cat ${your_script_name_here}; } | sqlplus
———————-
Sequent:
$ debug -c core $ORACLE_HOME/bin/sqlplus
debug> stack
debug> quit
———————-
Write a CRON job to:

1. Get the tablespace names from Oracle:
SELECT TABLESPACE_NAME FROM SYS.DBA_TABLESPACES;

2. Put the tablespaces in backup mode:
ALTER TABLESPACE … BEGIN BACKUP;

3. Get the database file names from Oracle:
SELECT NAME FROM SYS.V_$DATAFILE;
SELECT NAME FROM SYS.V_$CONTROLFILE;
SELECT MEMBER FROM SYS.V_$LOGFILE;

4. Backup the files using pax, tar, ufsdump, dd, cpio or whatever file copy command you fancy. Note that if your database is on a raw partition, you can only use dd. Some examples:

$ find . -depth -print | cpio -ocBv >/dev/tapedevice
$ dd if=/dev/raw_device of=/dev/tape_device BS=8k
$ pax -w -f archive.pax *

5. End backup mode for all the tablespaces.
ALTER TABLESPACE … END BACKUP;
————
One can select a value from a database column directly into a Unix environment variable. Look at the following shell script examples:

#!/bin/sh
VALUE=`sqlplus -silent user/password@instance <<END
set pagesize 0 feedback off verify off heading off echo off
select max(c1) from t1;
exit;
END`
if [ -z "$VALUE" ]; then
echo “No rows returned from database”
exit 0
else
echo $VALUE
fi

Second example, using the SQL*Plus EXIT status code (can only return integer values smaller than 256):

#!/bin/ksh
sqlplus -s >junk1 /nolog <<EOF
connect user/password@instance
column num_rows new_value num_rows format 9999
select count(*) num_rows
from table_name;
exit num_rows
EOF
echo “Number of rows are: $?”

Yet another example, only this time we will read multiple values from SQL*Plus into shell variables.

sqlplus -s /nolog |& # Open a pipe to SQL*Plus

print -p — ‘connect user/password@instance’
print -p — ‘set feed off pause off pages 0 head off veri off line 500′
print -p — ‘set term off time off’
print -p — “set sqlprompt ””

print -p — “select sysdate from dual;”
read -p SYSDATE

print -p — “select user from dual;”
read -p USER

print -p — “select global_name from global_name;”
read -p GLOBAL_NAME

print -p — exit

echo SYSDATE: $SYSDATE
echo USER: $USER
echo GLOBAL_NAME: $GLOBAL_NAME
——————————————
What is ORATAB and what is it used for?
The oratab file is normally located in the /etc or /var/opt/oracle directories. Originally ORATAB was used for SQL*Net V1. It contains comments in Unix-style leading pound signs (#), and data lines consisting of entries in the following format:

database_sid:oracle_home_dir:Y|N

==========================================
* SMON
The System Monitor carries out a crash recovery when a crashed insance is started up again. It also cleans temporary segments.
* PMON
The Process Monitor checks if a user process fails and if so, does all cleaning up of resources that the user process has aquired.
* DBWR
The Database Writer writes dirty blocks from the database buffer to the datafiles. How many DBWn Processes are started is determined by the initialization parameter DB_WRITER_PROCESSES. DBWR also writes the actual SCN with the Block.
* LGWR
The Log Writer writes the redo log buffer from the SGA to the online redo log file.
* MMAN
The memory manager
* MRP
Managed recovery process: the process that applies archived redo log to the standby database.
* RFS
The remote file server process on the standby database receives archived redo logs from the primary database.
* RECO
The Distributed Transaction Recovery Process finds pending (distributed) transaction and resolves them.
* CKPT
The Checkpoint Process reqularly initiates a checkpoint which uses DBWR to write all dirty blocks back to the datafiles, thus synchronizing the database. Since a Checkpoint records the current SCN, in a recovery only redo records with a SCN higher than that of the last checkpoint need to be applied.
* ARCH
The Archiver Process archives redo log files if ARCHIVELOG is enabled.
* Dnnn
The Dispatcher Process is used in a shared server environment.
* Snnn
The Shared Server Process is used in a shared server environment.
* LMON
The lock manager.
* LMD0
* QMNn
AQ Time Manager
* TRWR
Trace writer
* WMON
The wakeup monitor process.
* LCKnnn
Inter-instance locking process.
* SNPnnn
The snapshot process.
* MMON
New background process in Oracle 10g.
* DMON
The Data Guard Broker process.
* SNP
The snapshot process.

Background processes have v$session.type = ‘BACKGROUND’
cat /dev/null > /dev/ttyname kill –9 pid# (kill)
ps -ef|grep $ORACLE_SID| \
grep -v grep|awk ‘{print $2}’|xargs -i kill -9 {}

ipcs -pmb
ipcrm –m 24064 (release memory)

check processes
strace
truss -rall -wall -p <PID>
truss -p $ lsnrctl dbsnmp_start

echo pmon=$pmon + smon=$smon + dbwr=$dbwr + lgwr=$lgwr + chkpt=$ckpt + reco=$reco + arch=$arch + mman=$mman + mmon=$mmon
processes=`echo “$pmon+$smon+$dbwr+$lgwr+$ckpt+$reco+$arch” | bc`
echo $processes
if [ $ processes -eq 0 ]; then
echo Aborting – Database process ERROR
echo pmon=$pmon + smon=$smon + dbwr=$dbwr + lgwr=$lgwr + chkpt=$ckpt + reco=$reco + arch=$arch + mman=$mman + mmon=$mmon
mailx -s “Aborting -DAtabase process Error” $ email > /dev/null
exit 1
fi

check listener
listener=”`ps -eaf|grep lsnr|grep -v grep|wc -l`”
if [ $ processes -eq 1 ]; then
lsnr_SIDs=”`lsnrctl status |grep $2 | grep -v grep|wc -l`”
if [ $ processes -eq 0 ]; then
echo Aborting – listener configuration does not match SID parameter
mailx -s “Aborting -Listener Configuration does not match Error” $ email > /dev/null
exit 1
fi
else
i=0
while [ $listener -eq 0 ]; do
if [ $i -gt 1]; then
echo Aborting -listener is down -faile to restart
echo check $TNSADMIN/listenr.ora configuration
mailx -s “Aborting -listener is Down -failed to restart” $email > /dev/null
exit 1
fi
lsnrctl start
listener=”`ps -eaf|grep lsnr|grep -v grep|wc -l`”
i=`echo “$i+1″ |bc
done
fi

database state
$ORACLE_HOME/BIN/sqlplus $3<<!
connect sys;
set termout off echo off feed off trimspool on head off pages 0;
spool $ORALCE_SBIN/LOG/databseAlive.log;
select name from v$databse;
select open_mode from v$database;
spool off;
disconnect;
exit;
!

dbState=”`cat $ORACLE_SBIN/logs/databaseAlive.log|grep READ |grep -v grep|wc -l`”
if [ $dbState -eq 0 ]; then
echo Aborting – database for SID $e not open
mailx -s “Aborting -database for SID $e not open” $ email > /dev/null
exit 1
fi
=====================================================

Identify Tables That Need Space

This tip lets you identify tables that need more than a specified amount of space. This example uses a size of 1GB.

SELECT segment_type, SUBSTR (segment_name, 1, 30),
SUBSTR (tablespace_name, 1, 30),
SUM (TRUNC (BYTES / (1024 * 1024 * 1024), 2)) "size in GB"
FROM dba_segments
WHERE segment_type IN ('TABLE', 'TABLE PARTITION', 'TABLE SUBPARTITION')
AND owner IN ('BO_USER', 'DWH_OWNER', 'OWBTARGET', 'SM_OWNER')
HAVING SUM (TRUNC (BYTES / (1024 * 1024 * 1024), 2)) > 1
GROUP BY segment_type,
SUBSTR (segment_name, 1, 30),
SUBSTR (tablespace_name, 1, 30)

=====================================================

Open Cursor Count

This script reports the session-wise open cursor count, which can be helpful information when tuning the open_cursor parameter (in environments where application changes are frequent).


select substr(a.sid,1,10) sid,
substr(nvl(b.program,machine),1,30) program,
count(*)
from v$open_cursor a, v$session b
where a.saddr=b.saddr
group by substr(a.sid,1,10),
substr(nvl(b.program,machine),1,30)
order by 3 desc ;

=====================================================

Get Information on Current Queries

This script provides information about the queries that are currently using temporary segments. (This script runs on Oracle Database 10g.)

col tablespace for a8
col username for a10
col status for a8
col program for a15
col sql_text for a30
col blocks for 9999999
set linesize 350
set pagesize 300

alter session set nls_date_format='DD/MM/YYYY HHAM:MI:SS';

select t.tablespace_name as tablespace,us.username,s.status,s.sid,s.serial#,s.program,sql.sql_text,us.blocks,s.logon_time
from v$tempseg_usage us, v$session s, v$sqlarea sql, dba_tablespaces t
where t.contents = 'TEMPORARY' and
us.tablespace=t.tablespace_name and
us.session_addr = s.saddr and
s.sql_address = sql.address
order by blocks
/

=====================================================

Track CPU Usage

This query monitors CPU usage by session, showing information about processes running. It can identify the whole proccess tree.


select s.username "Oracle User",s.osuser "OS User",i.consistent_gets "Consistent Gets",
i.physical_reads "Physical Reads",s.status "Status",s.sid "SID",s.serial# "Serial#",
s.machine "Machine",s.program "Program",to_char(logon_time, 'DD/MM/YYYY HH24:MI:SS') "Logon Time",
w.seconds_in_wait "Idle Time", P.SPID "PROC",
name "Stat CPU", value
from v$session s, v$sess_io i, v$session_wait w, V$PROCESS P, v$statname n, v$sesstat t
where s.sid = i.sid
and s.sid = w.sid (+)
and 'SQL*Net message from client' = w.event(+)
and s.osuser is not null
and s.username is not null
and s.paddr=p.addr
and n.statistic# = t.statistic#
and n.name like '%cpu%'
and t.SID = s.sid
order by 6 asc, 3 desc, 4 desc

=====================================================

Putting files on a remote Server (Oracle/Unix)
Sometimes, when we are working with the Oracle database, we come across the need to put files on remote server which are to be picked up by some other process or we have to ftp file(s) for backups. One can transfer the file manually by using ftp either to put on the remote server or to get it from the remote server. Manual process has its own disadvantage as it requires human intervention. We can always automate the process and schedule it as a cronjob so that script gets invoked at specific time and file transfer takes place automatically. Following is the small shell script which automates the process of putting the file on the remote server. Cut and paste following text on a UNIX machine and save it as a shell file (.sh extension).

#!/bin/sh
ftp_server=”10.80.10.27″
exp_dir=”/home/oracle/decipher”

ftp -n ${ftp_server} << EOF
user ftpuser ftpuser\*
cd /customerdb/ora_bkup
lcd ${exp_dir}
bin
put decipher_backup.dmp
EOF

• First line indicates that we are using bourne shell. This is default for UNIX. Shell is nothing but the command interpreter. It reads command from the key board and executes it. When more than one command is put together in the file, it is called shell script. We can execute the shell script which in turn will execute all the commands within the script.
• Second and third lines, we are declaring variable and assigning value to it.
• Fourth line we are invoking ftp connection with –n option. When –n option is used, it turns off the automatic login and ftp client will not ask for userid and password to connect to remote server. If not, then it will try to login immediately and will prompt for userid and password. ‘<< ’ is a redirection syntax and indicates that anything defined after this will be considered as an input to the ftp command.
• On the fifth line, we are giving credentials to login to the remote server by providing userid and password.
• On the sixth line we are changing the directory where we want to put the file.
• Seventh line, we are using lcd command to change the directory on local machine and hence (lcd), from which we would like to transfer the file.
• On the eighth line, we are changing the transfer mode to binary. Default is ascii mode. If it is a zip file or export dump file, it is advisable to transfer it in binary mode otherwise during transfer it may get corrupted.
• In the ninth line, we are using put command to put the file on the remote server.
• 10th line indicates EOF, means redirection is over at this point. So if at all, any other command is used in the script after this point will not be considered as an input and will be executed individually.

In similar fashion, one can get the file from remote server using get command. Script can be enhanced further to check for the success or failure of ftp process as well.

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Oracle backup script for RAC clustering

Posted on 03. Mar, 2008 by sabin.

CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO
'/orabackup/rman/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 2 BACKUP TYPE TO BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL 1 DEVICE TYPE DISK CONNECT 'SYS/redhat@mars2';
CONFIGURE CHANNEL 2 DEVICE TYPE DISK CONNECT ' SYS/redhat@mars2';
CONFIGURE MAXSETSIZE TO UNLIMITED;
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO
'/orabackup/rman/snapcf_racdbtst1.f'; # default

configure controlfile autobackup format for device type disk to
'/orabackup/rman/ORA920/%F';

configure channel device type disk format
'/orabackup/rman/backup_db_%d_S_%s_P_%p_T_%t' ;

 #!/bin/csh -x
# rman_backup_as_copy_to_FS
# ----------------------------
# ----------------------------
# This script make a backup copy to file system
# This backup can be restored on File system as a regular hot backup
# Or can be restored to ASM by using rman
#
-------------------------------------------------------------------------------
# This script does: export ORACLE_SID=mars2
# 1) Administrative tasks:
# crosscheck
# delete obsolete
# 2) Archive log current on 1st Instance
# 3) Archive log current on 2nd Instance
# 4) Rman backup as copy to file system including controlfile and archivelogs
# 5) Archive log current on 1st Instance
# 6) Archive log current on 2nd Instance
# 7) Rman backup as copy archivelogs not backed up and print backupset
list to log
#
--------------------------------------------------------------------------------
# This script works with 2 nodes only, if you have more than 2 nodes you
need to customize it.
#
# This script use aliases and Environment variables set on .cshrc
# to setup the environment to point to the Database:
# setenv DBS_HOME /u01/app01/oracle/product/10gDB
# setenv BASE_PATH
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin
# alias 10db 'setenv $ORACLE_HOME $DBS_HOME; setenv PATH
$ORACLE_HOME/bin:$BASE_PATH'
# This script do require as parameters the 2 instance names
# It will use them to archive all required logs from instances 1 and 2
# --------------------------------------------------------------------
set v_inst1=mars2
set v_inst2=mars1
# Rman Backup Location variable
# -----------------------------
set v_rman_loc=/orabackup/rman
# Step 1: Administrative tasks, crosscheck and delete obsolete
# ------------------------------------------------------------
setenv ORACLE_SID $v_inst1
rman target / nocatalog <<EOF
crosscheck backupset;
crosscheck copy;
crosscheck archivelog all;
delete noprompt expired backup ;
delete noprompt obsolete;
exit
EOF
# This script run from 1st node. We use an external identified DBA user,
ops$oracle, to execute
# the archive log current. From the same session we connect as ops$oracle
into the 2nd instance
# You need remote_os_authent=TRUE on both instances to connect remotely
without password
# Step 2: Archive log current on 1st Instance
# Step 3: Archive log current on 2nd Instance
# -------------------------------------------
sqlplus -s sys/redhat@$v_inst1 << EOF
select instance_name from v\$instance
/
alter system archive log current
/
connect sys/redhat@$v_inst2;
select instance_name from v\$instance
/
alter system archive log current
/
exit
EOF
# On step 4 we use 4 channels. This needs to be customized according the
number of cpu's/IO
# channels available. Rman is invoked in nocatalog mode, we need to have
configured
# ORACLE_HOME, ORACLE_SID and PATH on the environment, as we did in the
previous steps.
# Step 4: Rman backup as copy to file system including controlfile and
archivelogs
#
--------------------------------------------------------------------------------
rman target / nocatalog <<EOF
run {
allocate channel backup_disk1 type disk format '$v_rman_loc/%U';
allocate channel backup_disk2 type disk format '$v_rman_loc/%U';
backup as COPY tag '%TAG' database include current controlfile;
release channel backup_disk1;
release channel backup_disk2;
}
exit
EOF
# Step 5 and 6: Archive log current on 1st and 2nd Instances
# ----------------------------------------------------------
sqlplus -s sys/redhat@$v_inst1 << EOF
select instance_name from v\$instance
/
alter system archive log current
/
connect sys/redhat@$v_inst2;
select instance_name from v\$instance
/
alter system archive log current
/
exit
EOF
# Step 7: Rman backup as copy archivelogs not backed up and print
backupset list to log
rman target / nocatalog <<EOF
backup as copy archivelog all format '$v_rman_loc/%d_AL_%T_%u_s%s_p%p' ;
list backupset;
exit
EOF
# Redirecting rman output to log will suppress standard output, because of
that
# running separately.
rman target / nocatalog log=$v_rman_loc/backupset_info.log <<EOF
list backup summary;
list backupset;
list backup of controlfile;
exit
EOF
# eof rman_backup_as_copy_to_FS

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Oracle some scripts

Posted on 20. Feb, 2008 by sabin.

http://www.oracle.com/technology/oramag/code/tips2005/010305.html

select substr(a.sid,1,10) sid,
substr(nvl(b.program,machine),1,30) program,
count(*)
from v$open_cursor a, v$session b
where a.saddr=b.saddr
group by substr(a.sid,1,10),
substr(nvl(b.program,machine),1,30)
order by 3 desc ;

Track and Monitor Resources

This tip comes from Luis Adalberto, DBA at Universidad Autonoma de Coahuila, in Saltillo, Coahuila, Mexico.

Running this query will produce a list of database statements and objects that are using the most resources.

Note: Execute as SYS user.

select V1.sid, V1.serial#, V2.USERNAME, V2.OSUSER, V1.opname, to_char(V1.start_t
ime, ‘HH24:MI:SS’) AS Started, (V1.SOFAR/V1.TOTALWORK)*100 AS Pct_completed
FROM V$SESSION_LONGOPS V1, V$SESSION V2
WHERE V1.SID= V2.SID AND V1.SERIAL#=V2.SERIAL#
AND (SOFAR/TOTALWORK)*100 < 100
AND TOTALWORK > 0

Track CPU Usage

This tip comes from Jony Safi, DBA at Videotron Ltee, in Montreal, Quebec,Canada.

This query monitors CPU usage by session, showing information about processes running. It can identify the whole proccess tree.

select s.username “Oracle User”,s.osuser “OS User”,i.consistent_gets “Consistent Gets”,
i.physical_reads “Physical Reads”,s.status “Status”,s.sid “SID”,s.serial# “Serial#”,
s.machine “Machine”,s.program “Program”,to_char(logon_time, ‘DD/MM/YYYY HH24:MI:SS’) “Logon Time”,
w.seconds_in_wait “Idle Time”, P.SPID “PROC”,
name “Stat CPU”, value
from v$session s, v$sess_io i, v$session_wait w, V$PROCESS P, v$statname n, v$sesstat t
where s.sid = i.sid
and s.sid = w.sid (+)
and ‘SQL*Net message from client’ = w.event(+)
and s.osuser is not null
and s.username is not null
and s.paddr=p.addr
and n.statistic# = t.statistic#
and n.name like ‘%cpu%’
and t.SID = s.sid
order by 6 asc, 3 desc, 4 desc

Check Transactions Occupying Rollback Segments

This tip comes from Vishwamithran S, Manager, DB Support, in Chennai, Tamilnadu, India.

This script checks transactions that occupy rollback segments for more than a day.

select substr(v$session.sid,1,8) sid,to_char(spid) spid,
to_char(process) process,substr(r.usn,1,6) usn,
substr(nvl(v$session.program,machine),1,20) program,
to_char(used_ublk*8192/1024/1024) used,
substr(event,1,18) event,
round(seconds_in_wait/(60*60),2) hr,
r.status,start_time,sysdate from
v$session,v$transaction,v$rollstat r,
v$session_wait, v$process
where saddr=ses_addr and
xidusn=r.usn and
v$session.sid=v$session_wait.sid and
paddr=v$process.addr and
to_date(start_time,’mm/dd/yy hh24:mi:ss’)

Output of the query gives the process value (the program’s PID). You can then check for the existence of the process at the OS level, and if it is not found, you can then clean up the corresponding Oracle shado

Generate Horizontal-to-Vertical

This tip comes from Ilya Petrenko, a Sr.Oracle DBA with Open Distributed Solutions, Inc., in Jamison, Pennsylvania.

This query takes a long string of data and breaks it out into smaller, separate strings.

set ver off
def Del=’@’
def String=”@0@11@222@3333@44444@555555@6666666@77777777@888888888″

select
Rownum Row#,
SUBSTR(A.Str||’&Del’
, INSTR(A.Str||’&Del’ , ‘&Del’, 1, Rownum ) +1
, INSTR(A.Str||’&Del’ , ‘&Del’, 1, Rownum+1)
-INSTR(A.Str||’&Del’ , ‘&Del’, 1, Rownum ) -1
) Token
From
(
select
‘&String’ Str
from dual
)
A,
all_objects B
where
Rownum< length(A.Str)-length(REPLACE(A.Str,’&Del’))+1
;

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Oracle Concepts and Architecture Database Structures.

Posted on 20. Feb, 2008 by sabin.

Oracle question bank

Oracle Concepts and Architecture Database Structures.

1. What are the components of Physical database structure of Oracle Database?.

ORACLE database is comprised of three types of files. One or more Data files, two are more Redo Log files, and one or more Control files.

2. What are the components of Logical database structure of ORACLE database?

Tablespaces and the Database’s Schema Objects.

3. What is a Tablespace?

A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.

4. What is SYSTEM tablespace and When is it Created?

Every ORACLE database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.

5. Explain the relationship among Database, Tablespace and Data file.

Each databases logically divided into one or more tablespaces One or more data files are explicitly created for each tablespace.

6. What is schema?

A schema is collection of database objects of a User.

7. What are Schema Objects ?

Schema objects are the logical structures that directly refer to the database’s data. Schema objects include tables,views,sequences,synonyms, indexes, clusters, database triggers, procedures, functions packages and database links.

8. Can objects of the same Schema reside in different tablespaces.?

Yes.

9. Can a Tablespace hold objects from different Schemes ?

Yes.

10. what is Table ?

A table is the basic unit of data storage in an ORACLE database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.

11. What is a View ? ( Combination of data by creating views of tables)

A view is a virtual table. Every view has a Query attached to it. (The Query is a SELECT statement that identifies the columns and rows of the table(s) the view uses.)

12. Do View contain Data ?

Views do not contain or store data.

13. Can a View based on another View ?

Yes.

14. What are the advantages of Views ?

? Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
? Hide data complexity.
? Simplify commands for the user.
? Present the data in a different perpecetive from that of the base table.
? Store complex queries.

15. What is a Sequence ?

A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.

16. What is a Synonym ?

A synonym is an alias for a table, view,sequence or program unit.

17. What are the type of Synonyms ?

There are two types of Synonyms Private and Public.

18. What is a Private Synonyms ?

A Private Synonyms can be accessed only by the owner.

19. What is a Public Synonyms ?

A Public synonyms can be accessed by any user on the database.

20. What are synonyms used for ?

Synonyms are used to : Mask the real name and owner of an object.
Provide public access to an object
Provide location transparency for tables,views or program units of a remote database.
Simplify the SQL statements for database users.

68. What is Cursor ?

A Cursor is a handle ( a name or pointer) for the memory associated with a specific statement

21. What is an Index ?

An Index is an optional structure associated with a table to have direct access to rows,which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.

22. How are Indexes Update ?

Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.

23. What are Clusters ?

Clusters are groups of one or more tables physically stores together to share common columns and are often used together.

24. What is cluster Key ?

The related columns of the tables in a cluster is called the Cluster Key.

25. What is Index Cluster ?

A Cluster with an index on the Cluster Key.

26. What is Hash Cluster ?

A row is stored in a hash cluster based on the result of applying a hash function to the row’s cluster key value. All rows with the same hash key value are stores together on disk.

27. When can Hash Cluster used ?

Hash clusters are better choice when a table is often queried with equality queries. For such queries the specified cluster key value is hashed. The resulting hash key value points directly to the area on disk that stores the specified rows.

111. What is a Procedure ?

A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a specific problem or perform a set of related tasks.

112. What is difference between Procedures and Functions ?

A Function returns a value to the caller where as a Procedure does not.

113. What is a Package ?

A Package is a collection of related procedures, functions, variables and other package constructs together as a unit in the database.

114. What are the advantages of having a Package ?

Increased functionality (for example,global package variables can be declared and used by any proecdure in the package) and performance (for example all objects of the package are parsed compiled, and loaded into memory once)

115. What is Database Trigger ?

A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a result of an insert in,update to, or delete from a table.

116. What are the uses of Database Trigger ?

Database triggers can be used to automatic data generation, audit data modifications, enforce complex Integrity constraints, and customize complex security authorizations.

117. What are the differences between Database Trigger and Integrity constraints ?

A declarative integrity constraint is a statement about the database that is always true.
A constraint applies to existing data in the table and any statement that manipulates the table.

A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not guarantee all data in a table conforms to the rules established by an associated trigger.

A trigger can be used to enforce transitional constraints where as a declarative integrity constraint cannot be used.

28. What is Database Link ?

A database link is a named object that describes a “path” from one database to another.

29. What are the types of Database Links ?

Private Database Link, Public Database Link & Network Database Link.

30. What is Private Database Link ?

Private database link is created on behalf of a specific user. A private database link can be used only when the owner of the link specifies a global object name in a SQL statement or in the definition of the owner’s views or procedures.

31. What is Public Database Link ?

Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.

32. What is Data Block ?

Network database link is created and managed by a network domain service. A network database link can be used when any user of any database in the network specifies a global object name in a SQL statement or object definition.

33. What is Data Block ?

ORACLE database’s data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.

34. How to define Data Block size ?

A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE datablocks. Block size is specified in INIT.ORA file and cann’t be changed latter.

35. What is Row Chaining ?

In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs , the data for the row is stored in a chain of data block (one or more) reserved for that segment.

36. What is an Extent ?

An Extent is a specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information.

37. What is a Segment ?

A segment is a set of extents allocated for a certain logical structure.

38. What are the different type of Segments ?

Data Segment, Index Segment, Rollback Segment and Temporary Segment.

39. What is a Data Segment ?

Each Non-clustered table has a data segment. All of the table’s data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster’s data segment.

40. What is an Index Segment ?

Each Index has an Index segment that stores all of its data.

41. What is Rollback Segment ?

A Database contains one or more Rollback Segments to temporarily store “undo” information.

42. What are the uses of Rollback Segment ?

Rollback Segments are used :To generate read-consistent database information during database recovery to rollback uncommitted transactions for users.

43. What is a Temporary Segment ?

Temporary segments are created by ORACLE when a SQL statement needs a temporary work area to complete execution. When the statement finishes execution, the temporary segment extents are released to the system for future use.

44. What is a Data File ?

Every ORACLE database has one or more physical data files. A database’s data files contain all the database data. The data of logical database structures such as tables and indexes is physically stored in the data files allocated for a database.

45. What are the Characteristics of Data Files ?

? A data file can be associated with only one database.
? Once created a data file can’t change size.
? One or more data files form a logical unit of database storage called a tablespace.

46. What is a Redo Log ?

The set of Redo Log files for a database is collectively known as the database’s redo log.

47. What is the function of Redo Log ?

The Primary function of the redo log is to record all changes made to data.

48. What is the use of Redo Log Information ?

The Information in a redo log file is used only to recover the database from a system or media failure the prevents database data from being written to a database’s data files.

49. What does a Control file Contain ?

A Control file records the physical structure of the database. It contains the following information.

? Database Name
? Names and locations of a database’s files and redolog files.
? Time stamp of database creation.

50. What is the use of Control File ?

When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.

51. What is a Data Dictionary ?

The data dictionary of an ORACLE database is a set of tables and views that are used a read-only reference about the database.

It stores information about both the logical and physical structure of the database, the valid users of an ORACLE database, integrity constraints defined for tables in the database and
space allocated for a schema object and how much of it is being used.

52. What is an Integrity Constrains ?

An integrity constraint is a declarative way to define a business rule for a column of a table.

53. Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ?

No.

54. Describe the different type of Integrity Constraints supported by ORACLE ?

NOT NULL Constraint – Disallows NULLs in a table’s column.
UNIQUE Constraint – Disallows duplicate values in a column or set of columns.
PRIMARY KEY Constraint – Disallows duplicate values and NULLs in a column or set of columns.
FOREIGN KEY Constrain – Require each value in a column or set of columns match a value in a related table’s UNIQUE or PRIMARY
KEY.
CHECK Constraint – Disallows values that do not satisfy the logical expression of the
constraint.

55. What is difference between UNIQUE constraint and PRIMARY KEY constraint ?

A column defined as UNIQUE can contain NULLs while a column defined as
PERIMETER KEY can’t contain Nulls.

56. Describe Referential Integrity ?

A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data
manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced data.

57. What are the Referential actions supported by FOREIGN KEY integrity
constraint ?

UPDATE and DELETE Restrict – A referential integrity rule that disallows the update or deletion of referenced data.

DELETE Cascade – When a referenced row is deleted all associated dependent rows are deleted.

58. What is self-referential integrity constraint ?

If a foreign key reference a parent key of the same table is called self-referential integrity constraint.

59. What are the Limitations of a CHECK Constraint ?

The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can’t contain subqueries,sequence,the SYSDATE,UID,USER or USERENV SQL functions, or the pseudocolumns LEVEL or ROWNUM.

60. What is the maximum number of CHECK constraints that can be defined on a column ?

No Limit.

SYSTEM ARCHITECTURE :

61. What constitute an ORACLE Instance ?

SGA and ORACLE background processes constitute an ORACLE instance. (or)
Combination of memory structure and background process.

62. What is SGA ?

The System Global Area (SGA) is a shared memory region allocated by ORACLE that contains data and control information for one ORACLE instance.

63. What are the components of SGA ?

Database buffers, Redo Log Buffer the Shared Pool and Cursors.

64. What do Database Buffers contain ?

Database buffers store the most recently used blocks of database data. It can also contain modified data that has not yet been permanently written to disk.

65. What do Redo Log Buffers contain ?

Redo Log Buffer stores redo entries a log of changes made to the database.

66. What is Shared Pool ?

Shared Pool is a portion of the SGA that contains shared memory constructs such as shared SQL areas.

67. What is Shared SQL Area ?

A Shared SQL area is required to process every unique SQL statement submitted to a database and contains information such as the parse tree and execution plan for the corresponding statement.

68. What is Cursor ?

A Cursor is a handle ( a name or pointer) for the memory associated with a specific statement.

69. What is PGA ?

Program Global Area (PGA) is a memory buffer that contains data and control information for a server process.

70. What is User Process ?

A user process is created and maintained to execute the software code of an application program. It is a shadow process created automatically to facilitate communication between the user and the server process.

71. What is Server Process ?

Server Process handle requests from connected user process. A server process is in charge of communicating with the user process and interacting with ORACLE carry out requests of the associated user process.

72. What are the two types of Server Configurations ?

Dedicated Server Configuration and Multi-threaded Server Configuration.

73. What is Dedicated Server Configuration ?

In a Dedicated Server Configuration a Server Process handles requests for a Single User Process.

74. What is a Multi-threaded Server Configuration ?

In a Multi-threaded Server Configuration many user process share a group of server process.

75. What is a Parallel Server option in ORACLE ?

A configuration for loosely coupled systems where multiple instance share a single physical database is called Parallel Server.

76. Name the ORACLE Background Process ?

DBWR – Database Writer.
LGWR – Log Writer
CKPT – Check Point
SMON – System Monitor
PMON – Process Monitor
ARCH – Archiver
RECO – Recover
Dnnn – Dispatcher, and
LCKn – Lock
Snnn – Server.

77. What Does DBWR do ?

Database writer modified blocks from the database buffer
cache to the data files.

78.When Does DBWR write to the database ?

DBWR writes when more data needs to be read into the SGA and too few are database
buffers free. The least recently used data is written to the data files first. DBWR also writes
when CheckPoint occurs.

79. What does LGWR do ?

Log Writer (LGWR) writes redo log entries generated in the redo log buffer of the SGA to
on-line Redo Log File.

80. When does LGWR write to the database ?

LGWR writes redo log entries into an on-line redo log file when transactions commit and
the log buffer files.

81. What is the function of checkpoint(CKPT)?

The Checkpoint (CKPT) process is responsible for signaling DBWR at checkpoints and
updating all the data files and control files of the database.

82. What are the functions of SMON ?

System Monitor (SMON) performs instance recovery at instance start-up. In a multiple
instance system (one that uses the Parallel Server), SMON of one instance can also
perform instance recovery for other instance that have failed SMON also cleans up
temporary segments that are no longer in use and recovers dead transactions skipped
during crash and instance recovery because of file-read or off-line errors. These
transactions are eventually recovered by SMON when the tablespace or file is brought
back on-line SMON also coalesces free extents within the database to make free space
contiguous and easier to allocate.

83. What are functions of PMON ?

Process Monitor (PMON) performs process recovery when a user process fails PMON is
responsible for cleaning up the cache and Freeing resources that the process was using
PMON also checks on dispatcher and server processes and restarts them if they have
failed.

84. What is the function of ARCH ?

Archiver (ARCH) copies the on-line redo log files to archival storage when they are full.
ARCH is active only when a database’s redo log is used in ARCHIVELOG mode.

85. What is function of RECO ?

RECOver (RECO) is used to resolve distributed transactions that are pending due to a
network or system failure in a distributed database. At timed intervals,the local RECO
attempts to connect to remote databases and automatically complete the commit or rollback
of the local portion of any pending distributed transactions.

86. What is the function of Dispatcher (Dnnn) ?

Dispatcher (Dnnn) process is responsible for routing requests from connected user
processes to available shared server processes and returning the responses back to the
appropriate user processes.

87. How many Dispatcher Processes are created ?

Atleast one Dispatcher process is created for every communication protocol in use.

88. What is the function of Lock (LCKn) Process ?

Lock (LCKn) are used for inter-instance locking when the ORACLE Parallel Server option
is used.

89. What is the maximum number of Lock Processes used ?

Though a single LCK process us sufficient for most Parallel Server systems upto Ten Locks
(LCK0,….LCK9) are used for inter-instance locking.

DATA ACCESS

90. Define Transaction ?

A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user.

91. When does a Transaction end ?

When it is committed or Rollbacked.

92. What does COMMIT do ?

COMMIT makes permanent the changes resulting from all SQL statements in the transaction. The changes made by the SQL statements of a transaction become visible to other user sessions transactions that start only after transaction is committed.

93. What does ROLLBACK do ?

ROLLBACK retracts any of the changes resulting from the SQL statements in the transaction.

94. What is SAVE POINT ?

For long transactions that contain many SQL statements, intermediate markers or savepoints can be declared which can be used to divide a transaction into smaller parts.
This allows the option of later rolling back all work performed from the current point in the transaction to a declared savepoint within the transaction.

95. What is Read-Only Transaction ?

A Read-Only transaction ensures that the results of each query executed in the transaction are consistence with respect to the same point in time.

96. What is the function Optimizer ?

The goal of the optimizer is to choose the most efficient way to execute a SQL statement.

97. What is Execution Plan ?

The combinations of the steps the optimizer chooses to execute a statement is called an
execution plan.

98. What are the different approaches used by Optimizer in choosing an execution plan ?

Rule-based and Cost-based.

99. What are the factors that affect OPTIMIZER in choosing an Optimization approach ?

The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the
OPTIMIZER_GOAL parameter of the ALTER SESSION command hints in the
statement.

100.What are the values that can be specified for OPTIMIZER MODE Parameter ?

COST and RULE.

101. With the Optimizer always use COST-based approach if OPTIMIZER_MODE is set to “Cost’?

Presence of statistics in the data dictionary for atleast one of the tables accessed by the SQL statements is necessary for the OPTIMIZER to use COST-based approach.
Otherwise OPTIMIZER chooses RULE-based approach.

102. What is the effect of setting the value of OPTIMIZER_MODE to ‘RULE’ ?

This value causes the optimizer to choose the rule_based approach for all SQL statements
issued to the instance regardless of the presence of statistics.

103. What are the values that can be specified for OPTIMIZER_GOAL parameter
of the ALTER SESSION Command ?

CHOOSE,ALL_ROWS,FIRST_ROWS and RULE.

104. What is the effect of setting the value “CHOOSE” for OPTIMIZER_GOAL,
parameter of the ALTER SESSION Command ?

The Optimizer chooses Cost_based approach and optimizes with the goal of best
throughput if statistics for atlas one of the tables accessed by the SQL statement exist in the
data dictionary. Otherwise the OPTIMIZER chooses RULE_based approach.

105. What is the effect of setting the value “ALL_ROWS” for
OPTIMIZER_GOAL parameter of the ALTER SESSION command ?

This value causes the optimizer to the cost-based approach for all SQL statements in the
session regardless of the presence of statistics and to optimize with a goal of best
throughput.

106. What is the effect of setting the value ‘FIRST_ROWS’ for
OPTIMIZER_GOAL parameter of the ALTER SESSION command ?

This value causes the optimizer to use the cost-based approach for all SQL statements in
the session regardless of the presence of statistics and to optimize with a goal of best
response time.

107. What is the effect of setting the ‘RULE’ for OPTIMIER_GOAL parameter of
the ALTER SESSION Command ?

This value causes the optimizer to choose the rule-based approach for all SQL statements
in a session regardless of the presence of statistics.

108. What is RULE-based approach to optimization ?

Choosing an executing planbased on the access paths available and the ranks of these
access paths.

109. What is COST-based approach to optimization ?

Considering available access paths and determining the most efficient execution plan based
on statistics in the data dictionary for the tables accessed by the statement and their
associated clusters and indexes.

PROGRAMMATIC CONSTRUCTS

110. What are the different types of PL/SQL program units that can be defined and stored in ORACLE database ?

Procedures and Functions,Packages and Database Triggers.

111. What is a Procedure ?

A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a specific problem or perform a set of related tasks.

112. What is difference between Procedures and Functions ?

A Function returns a value to the caller where as a Procedure does not.

113. What is a Package ?

A Package is a collection of related procedures, functions, variables and other package constructs together as a unit in the database.

114. What are the advantages of having a Package ?

115. What is Database Trigger ?

A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a result of an insert in,update to, or delete from a table.

116. What are the uses of Database Trigger ?

Database triggers can be used to automatic data generation, audit data modifications, enforce complex Integrity constraints, and customize complex security authorizations.

117. What are the differences between Database Trigger and Integrity constraints ?

A declarative integrity constraint is a statement about the database that is always true.
A constraint applies to existing data in the table and any statement that manipulates the table.

A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not guarantee all data in a table conforms to the rules established by an associated trigger.

A trigger can be used to enforce transitional constraints where as a declarative integrity constraint cannot be used.

DATABASE SECURITY

118. What are Roles ?

Roles are named groups of related privileges that are granted to users or other roles.

119. What are the use of Roles ?

REDUCED GRANTING OF PRIVILEGES – Rather than explicitly granting the same set of privileges to many users a database administrator can grant the privileges for a group of related users granted to a role and then grant only the role to each member of the group.

DYNAMIC PRIVILEGE MANAGEMENT – When the privileges of a group must
change, only the privileges of the role need to be modified. The security domains of all users granted the group’s role automatically reflect the changes made to the role.

SELECTIVE AVAILABILITY OF PRIVILEGES – The roles granted to a user can be selectively enable (available for use) or disabled (not available for use). This allows specific control of a user’s privileges in any given situation.

APPLICATION AWARENESS – A database application can be designed to
automatically enable and disable selective roles when a user attempts to use the application.

120. How to prevent unauthorized use of privileges granted to a Role ?

By creating a Role with a password.

121. What is default tablespace ?

The Tablespace to contain schema objects created without specifying a tablespace name.

122. What is Tablespace Quota ?

The collective amount of disk space available to the objects in a schema on a particular tablespace.

123. What is a profile ?

Each database user is assigned a Profile that specifies limitations on various system resources available to the user.

124. What are the system resources that can be controlled through Profile ?

The number of concurrent sessions the user can establish the CPU processing time available to
the user’s session the CPU processing time available to a single call to ORACLE made by a
SQL statement the amount of logical I/O available to the user’s session the amout of logical I/O
available to a single call to ORACLE made by a SQL statement the allowed amount of idle time
for the user’s session the allowed amount of connect time for the user’s session.

125. What is Auditing ?

Monitoring of user access to aid in the investigation of database use.

126. What are the different Levels of Auditing ?

Statement Auditing, Privilege Auditing and Object Auditing.

127. What is Statement Auditing ?

Statement auditing is the auditing of the powerful system privileges without regard to specifically named objects.

128. What is Privilege Auditing ?

Privilege auditing is the auditing of the use of powerful system privileges without regard to specifically named objects.

129. What is Object Auditing ?

Object auditing is the auditing of accesses to specific schema objects without regard to user.

DISTRIBUTED PROCESSING AND DISTRIBUTED DATABASES

130. What is Distributed database ?

A distributed database is a network of databases managed by multiple database servers that appears to a user as single logical database. The data of all databases in the distributed database can be simultaneously accessed and modified.

131. What is Two-Phase Commit ?

Two-phase commit is mechanism that guarantees a distributed transaction either commits on all involved nodes or rolls back on all involved nodes to maintain data consistency across the global distributed database. It has two phase, a Prepare Phase and a Commit Phase.

132. Describe two phases of Two-phase commit ?

Prepare phase – The global coordinator (initiating node) ask a participants to prepare (to promise to commit or rollback the transaction, even if there is a failure)

Commit – Phase – If all participants respond to the coordinator that they are prepared, the coordinator asks all nodes to commit the transaction, if all participants cannot prepare, the coordinator asks all nodes to roll back the transaction.

133. What is the mechanism provided by ORACLE for table replication ?

Snapshots and SNAPSHOT LOGs

134. What is a SNAPSHOT ?

Snapshots are read-only copies of a master table located on a remote node which is periodically refreshed to reflect changes made to the master table.

135. What is a SNAPSHOT LOG ?

A snapshot log is a table in the master database that is associated with the master table. ORACLE uses a snapshot log to track the rows that have been updated in the master table. Snapshot logs are used in updating the snapshots based on the master table.

136. What is a SQL * NET?

SQL *NET is ORACLE’s mechanism for interfacing with the communication protocols used by the networks that facilitate distributed processing and distributed databases. It is used in Clint-Server and Server-Server communications.

DATABASE OPERATION, BACKUP AND RECOVERY

137. What are the steps involved in Database Startup ?

Start an instance, Mount the Database and Open the Database.

138. What are the steps involved in Database Shutdown ?

Close the Database, Dismount the Database and Shutdown the Instance.

139. What is Restricted Mode of Instance Startup ?

An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been
granted the RESTRICTED SESSION system privilege.

140What are the different modes of mounting a Database with the Parallel Server ?

Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database.

Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database.

141. What is Full Backup ?

A full backup is an operating system backup of all data files, on-line redo log files and control file that constitution ORACLE database and the parameter.

142. Can Full Backup be performed when the database is open ?

No.

143. What is Partial Backup ?

A Partial Backup is any operating system backup short of a full backup, taken while the database is open or shut down.

144. What is On-line Redo Log ?

The On-line Redo Log is a set of tow or more on-line redo files that record all committed changes made to the database. Whenever a transaction is committed, the corresponding redo entries temporarily stores in redo log buffers of the SGA are written to an on-line redo
log file by the background process LGWR. The on-line redo log files are used in cyclical fashion.

145. What is Mirrored on-line Redo Log ?

A mirrored on-line redo log consists of copies of on-line redo log files physically located on separate disks, changes made to one member of the group are made to all members.

146. What is Archived Redo Log ?

Archived Redo Log consists of Redo Log files that have archived before being reused.

147. What are the advantages of operating a database in ARCHIVELOG mode over
operating it in NO ARCHIVELOG mode ?

Complete database recovery from disk failure is possible only in ARCHIVELOG mode.
Online database backup is possible only in ARCHIVELOG mode.

148. What is Log Switch ?

The point at which ORACLE ends writing to one online redo log file and begins writing to
another is called a log switch.

149. What are the steps involved in Instance Recovery ?

Rolling forward to recover data that has not been recorded in data files, yet has been
recorded in the on-line redo log, including the contents of rollback segments.

Rolling back transactions that have been explicitly rolled back or have not been committed
as indicated by the rollback segments regenerated in step a.

Releasing any resources (locks) held by transactions in process at the time of the failure.

Resolving any pending distributed transactions undergoing a two-phase commit at the time
of the instance failure.

Data Base Administration.

Introduction to DBA

1. What is a Database instance ? Explain

A database instance (Server) is a set of memory structure and background processes that
access a set of database files.

The process can be shared by all users.

The memory structure that are used to store most queried data from database. This helps
up to improve database performance by decreasing the amount of I/O performed against
data file.

2. What is Parallel Server ?

Multiple instances accessing the same database (Only In Multi-CPU environments)

3. What is a Schema ?

The set of objects owned by user account is called the schema.

4. What is an Index ? How it is implemented in Oracle Database ?

An index is a database structure used by the server to have direct access of a row in a table.

An index is automatically created when a unique of primary key constraint clause is specified in create table comman (Ver 7.0)

5. What is clusters ?

Group of tables physically stored together because they share common columns and are often used together is called Cluster.

6. What is a cluster Key ?

The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.

7. What are the basic element of Base configuration of an oracle Database ?

It consists of
one or more data files.
one or more control files.
two or more redo log files.
The Database contains
multiple users/schemas
one or more rollback segments
one or more tablespaces
Data dictionary tables
User objects (table,indexes,views etc.,)
The server that access the database consists of
SGA (Database buffer, Dictionary Cache Buffers, Redo log buffers, Shared SQL pool)
SMON (System MONito)
PMON (Process MONitor)
LGWR (LoG Write)
DBWR (Data Base Write)
ARCH (ARCHiver)
CKPT (Check Point)
RECO
Dispatcher
User Process with associated PGS

8. What is a deadlock ? Explain .

Two processes wating to update the rows of a table which are locked by the other process
then deadlock arises.

In a database environment this will often happen because of not issuing proper row lock
commands. Poor design of front-end application may cause this situation and the
performance of server will reduce drastically.

These locks will be released automatically when a commit/rollback operation performed or
any one of this processes being killed externally.

MEMORY MANAGEMENT

9. What is SGA ? How it is different from Ver 6.0 and Ver 7.0 ?

The System Global Area in a Oracle database is the area in memory to facilitates the
transfer of information between users. It holds the most recently requested structural
information between users. It holds the most recently requested structural information about
the databse.

The structure is Database buffers, Dictionary cache, Redo Log Buffer and Shared SQL
pool (ver 7.0 only) area.

10. What is a Shared SQL pool ?

The data dictionary cache is stored in an area in SGA called the Shared SQL Pool. This
will allow sharing of parsed SQL statements among concurrent users.

11. What is mean by Program Global Area (PGA) ?

It is area in memory that is used by a Single Oracle User Process.

12. What is a data segment ?

Data segment are the physical areas within a database block in which the data associated
with tables and clusters are stored.

13. What are the factors causing the reparsing of SQL statements in SGA ?

Due to insufficient Shared SQL pool size.

Monitor the ratio of the reloads takes place while executing SQL statements. If the ratio is
greater than 1 then increase the SHARED_POOL_SIZE.

LOGICAL & PHYSICAL ARCHITECTURE OF DATABASE.

14. What is Database Buffers ?

Database buffers are cache in the SGA used to hold the data blocks that are read from the
data segments in the database such as tables, indexes and clusters
DB_BLOCK_BUFFERS parameter in INIT.ORA decides the size.

15. What is dictionary cache ?

Dictionary cache is information about the databse objects stored in a data dictionary table.

16. What is meant by recursive hints ?

Number of times processes repeatedly query the dictionary table is called recursive hints. It
is due to the data dictionary cache is too small. By increasing the SHARED_POOL_SIZE
parameter we can optimize the size of Data Dictionary Cache.

17. What is meant by redo log buffer ?

Change made to entries are written to the on-line redo log files. So that they can be used in
roll forward operations during database recoveries. Before writing them into the redo log
files, they will first brought to redo log buffers in SGA and LGWR will write into files
frequently. LOG_BUFFER parameter will decide the size.

18. How will you swap objects into a different table space for an existing database ?

Export the user

Perform import using the command imp system/manager file=export.dmp
indexfile=newrite.sql. This will create all definitions into newfile.sql.

Drop necessary objects.

Run the script newfile.sql after altering the tablespaces.

Import from the backup for the necessary objects.

19. List the Optional Flexible Architecture (OFA) of Oracle database ? or How can we
organise the tablespaces in Oracle database to have maximum performance ?

SYSTEM – Data dictionary tables.
DATA – Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES – Indexes for Standard operational tables.
INDEXES1 – Indexes of static tables used for standard operations.
TOOLS – Tools table.
TOOLS1 – Indexes for tools table.
RBS – Standard Operations Rollback Segments,
RBS1,RBS2 – Additional/Special Rollback segments.
TEMP – Temporary purpose tablespace
TEMP_USER – Temporary tablespace for users.
USERS – User tablespace.

20. How will you force database to use particular rollback segment ?

SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.

21. What is meant by free extent ?

A free extent is a collection of continuous free blocks in tablespace. When a segment is
dropped its extents are reallocated and are marked as free.

22. How free extents are managed in Ver 6.0 and Ver 7.0 ?

Free extents cannot be merged together in Ver 6.0.
Free extents are periodically coalesces with the neighboring free extent in Ver 7.0

23.Which parameter in Storage clause will reduce no. of rows per block ?

PCTFREE parameter

Row size also reduces no of rows per block.

24. What is the significance of having storage clause ?

We can plan the storage for a table as how mach initial extents are required, how much can
be extended next, how much % should leave free for managing row updations etc.,

25. How does Space allocation table place within a block ?

? Each block contains entries as follows
? Fixied block header
? Variable block header
? Row Header,row date (multiple rows may exists)
? PCTEREE (% of free space for row updation in future)

26. What is the role of PCTFREE parameter is Storage clause ?

This is used to reserve certain amount of space in a block for expansion of rows.

27. What is the OPTIMAL parameter ?

It is used to set the optimal length of a rollback segment.

28. What is the functionality of SYSTEM table space ?

To manage the database level transactions such as modifications of the data dictionary table
that record information about the free space usage.

29. How will you create multiple rollback segments in a database ?

Create a database which implicitly creates a SYSTEM Rollback Segment in a SYSTEM
tablespace.

Create a Second Rollback Segment name R0 in the SYSTEM tablespace.

Make new rollback segment available (After shutdown, modify init.ora file and Start
database)

Create other tablespaces (RBS) for rollback segments.

Deactivate Rollback Segment R0 and activate the newly created rollback segments.

30. How the space utilisation takes place within rollback segments ?

It will try to fit the transaction in a cyclic fashion to all existing extents. Once it found an
extent is in use then it forced to acquire a new extent (No. of extents is based on the optimal
size)

31. Why query fails sometimes ?

Rollback segment dynamically extent to handle larger transactions entry loads.

A single transaction may wipeout all avaliable free space in the Rollback Segment
Tablespace. This prevents other user using Rollback segments.

32. How will you monitor the space allocation ?

By quering DBA_SEGMENT table/view.

33. How will you monitor rollback segment status ?

Querying the DBA_ROLLBACK_SEGS view
IN USE – Rollback Segment is on-line.
AVAILABLE – Rollback Segment available but not on-line.
OFF-LINE – Rollback Segment off-line
INVALID – Rollback Segment Dropped.
NEEDS RECOVERY – Contains data but need recovery or corupted.
PARTLY AVAILABLE – Contains data from an unresolved transaction involving a
distributed database.

34. List the sequence of events when a large transaction that exceeds beyond its
optimal value when an entry wraps and causes the rollback segment to expand into
another extend.

Transaction Begins.

An entry is made in the RES header for new transactions entry

Transaction acquires blocks in an extent of RBS

The entry attempts to wrap into second extent. None is available, so that the RBS must
extent.

The RBS checks to see if it is part of its OPTIMAL size.
RBS chooses its oldest inactive segment.
Oldest inactive segment is eliminated.
RBS extents
The Data dictionary table for space management are updated.
Transaction Completes.

35. How can we plan storage for very large tables ?

Limit the number of extents in the table
Separate Table from its indexes.
Allocate Sufficient temporary storage.

36. How will you estimate the space required by a non-clustered tables ?

? Calculate the total header size
? Calculate the available dataspace per data block
? Calculate the combined column lengths of the average row
? Calculate the total average row size.
? Calculate the average number rows that can fit in a block
? Calculate the number of blocks and bytes required for the table.

After arriving the calculation, add 10 % additional space to calculate the initial extent size
for a working table.

37. It is possible to use raw devices as data files and what is the advantages over file.
system files ?

Yes.

The advantages over file system files.

I/O will be improved because Oracle is bye-passing the kernnel whicl writing into disk.
Disk Corruption will be very less.

38. What is a Control file ?

Database’s overall physical architecture is maintained in a file called control file. It will be
used to maintain internal consistency and guide recovery operations. Multiple copies of
control files are advisable.

39. How to implement the multiple control files for an existing database ?

Shutdown the databse
Copy one of the existing control file to new location
Edit Config ora file by adding new control file.name
Restart the database.

40. What is meant by Redo Log file mirrorring ? How it can be achieved ?

Process of having a copy of redo log files is called mirroring.

This can be achieved by creating group of log files together, so that LGWR will
automatically writes them to all the members of the current on-line redo log group. If any
one group fails then database automatically switch over to next group. It degrades
performance.

41. What is advantage of having disk shadowing/ Mirroring ?

Shadow set of disks save as a backup in the event of disk failure. In most Operating
System if any disk failure occurs it automatically switchover to place of failed disk.

Improved performance because most OS support volume shadowing can direct file I/O
request to use the shadow set of files instead of the main set of files. This reduces I/O load
on the main set of disks.

42. What is use of Rollback Segments In Database ?

They allow the database to maintain read consistency between multiple transactions.

43. What is a Rollback segment entry ?

It is the set of before image data blocks that contain rows that are modified by a
transaction.
Each Rollback Segment entry must be completed within one rollback segment.

A single rollback segment can have multiple rollback segment entries.

44. What is hit ratio ?

It is a measure of well the data cache buffer is handling requests for data.

Hit Ratio = (Logical Reads – Physical Reads – Hits Misses)/ Logical Reads.

45. When will be a segment released ?

When Segment is dropped.
When Shrink (RBS only)
When truncated (TRUNCATE used with drop storage option)

46. What are disadvanteges of having raw devices ?

We should depend on export/import utility for backup/recovery (fully reliable)

The tar command cannot be used for physical file backup, instead we can use dd command
which is less flexible and has limited recoveries.

47. List the factors that can affect the accuracy of the estimations ?

The space used transaction entries and deleted records does not become free immediately
after completion due to delayed cleanout.

Trailling nulls and length bytes are not stored.

Inserts of, updates to and deletes of rows as well as columns larger than a single datablock,
can cause fragmentation an chained row pieces.

DATABASE SECURITY & ADMINISTRATION

48. What is user Account in Oracle database ?

An user account is not a physical structure in Database but it is having important relationship
to the objects in the database and will be having certain privileges.

49. How will you enforce security using stored procedures ?

Don’t grant user access directly to tables within the application.

Instead grant the ability to access the procedures that access the tables.

When procedure executed it will execute the privilege of procedures owner. Users cannot
access tables except via the procedure.

50. What are the dictionary tables used to monitor a database spaces ?

DBA_FREE_SPACE
DBA_SEGMENTS
DBA_DATA_FILES.

51. What are the responsibilities of a Database Administrator ?

.Installing and upgrading the Oracle Server and application tools.
.Allocating system storage and planning future storage requirements for the database
system.
.Managing primary database structures (tablespaces)
.Managing primary objects (table,views,indexes)
.Enrolling users and maintaining system security.
.Ensuring compliance with Oralce license agreement
.Controlling and monitoring user access to the database.
.Monitoring and optimising the performance of the database.
.Planning for backup and recovery of database information.
.Maintain archived data on tape
.Backing up and restoring the database.
.Contacting Oracle Corporation for technical support.

52. What are the roles and user accounts created automatically with the database ?

DBA – role Contains all database system privileges.

SYS user account – The DBA role will be assigned to this account. All of the basetables
and views for the database’s dictionary are store in this schema and are manipulated only by
ORACLE.

SYSTEM user account – It has all the system privileges for the database and additional
tables and views that display administrative information and internal tables and views used
by oracle tools are created using this username.

54. What are the database administrators utilities avaliable ?

SQL * DBA – This allows DBA to monitor and control an ORACLE database.

SQL * Loader – It loads data from standard operating system files (Flat files) into
ORACLE database tables.

Export (EXP) and Import (imp) utilities allow you to move existing data in ORACLE format
to and from ORACLE database.

55. What are the minimum parameters should exist in the parameter file (init.ora) ?

DB NAME – Must set to a text string of no more than 8 characters and it will be stored
inside the datafiles, redo log files and control files and control file while database creation.

DB_DOMAIN – It is string that specifies the network domain where the database is
created. The global database name is identified by setting these parameters (DB_NAME &
DB_DOMAIN)

CONTORL FILES – List of control filenames of the database. If name is not mentioned
then default name will be used.

DB_BLOCK_BUFFERS – To determine the no of buffers in the buffer cache in SGA.

PROCESSES – To determine number of operating system processes that can be connected
to ORACLE concurrently. The value should be 5 (background process) and additional 1
for each user.

ROLLBACK_SEGMENTS – List of rollback segments an ORACLE instance acquires at
database startup.

Also optionally LICENSE_MAX_SESSIONS,LICENSE_SESSION_WARNING and
LICENSE_MAX_USERS.

56. What is a trace file and how is it created ?

Each server and background process can write an associated trace file. When an internal
error is detected by a process or user process, it dumps information about the error to its
trace. This can be used for tuning the database.

57. What are roles ? How can we implement roles ?

Roles are the easiest way to grant and manage common privileges needed by different
groups of database users.

Creating roles and assigning provies to roles.

Assign each role to group of users. This will simplify the job of assigning privileges to
individual users.

58. What are the steps to switch a database’s archiving mode between NO
ARCHIVELOG and ARCHIVELOG mode ?

1. Shutdown the database instance.
2. Backup the databse
3. Perform any operating system specific steps (optional)
4. Start up a new instance and mount but do not open the databse.
5. Switch the databse’s archiving mode.

59. How can you enable automatic archiving ?

Shut the database
Backup the database
Modify/Include LOG_ARCHIVE_START_TRUE in init.ora file.
Start up the databse.

60. How can we specify the Archived log file name format and destination ?

By setting the following values in init.ora file.

LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S – Log sequence number and is zero
left paded, %s – Log sequence number not padded. %T – Thread number lef-zero-paded
and %t – Thread number not padded). The file name created is arch 0001 are if %S is
used.
LOG_ARCHIVE_DEST = path.

61. What is the use of ANALYZE command ?

To perform one of these function on an index,table, or cluster:

- to collect statisties about object used by the optimizer and store them in the data
dictionary.
- to delete statistics about the object used by object from the data dictionary.
- to validate the structure of the object.
- to identify migrated and chained rows of the table or cluster.

MANAGING DISTRIBUTED DATABASES.

62. How can we reduce the network traffic ?

- Replictaion of data in distributed environment.
- Using snapshots to replicate data.
- Using remote procedure calls.

63. What is snapshots ?

Snapshot is an object used to dynamically replicate data between distribute database at
specified time intervals. In ver 7.0 they are read only.

64. What are the various type of snapshots ?

Simple and Complex.

65. Differentiate simple and complex, snapshots ?

- A simple snapshot is based on a query that does not contains GROUP BY clauses,
CONNECT BY clauses, JOINs, sub-query or snashot of operations.
- A complex snapshots contain atleast any one of the above.

66. What dynamic data replication ?

Updating or Inserting records in remote database through database triggers. It may fail if
remote database is having any problem.

67. How can you Enforce Refrencial Integrity in snapshots ?

Time the references to occur when master tables are not in use.
Peform the reference the manually immdiately locking the master tables.
We can join tables in snopshots by creating a complex snapshots that will based on the
master tables.

68. What are the options available to refresh snapshots ?

COMPLETE – Tables are completly regenerated using the snapshot’s query and the
master tables every time the snapshot referenced.
FAST – If simple snapshot used then a snapshot log can be used to send the changes to the
snapshot tables.
FORCE – Default value. If possible it performs a FAST refresh; Otherwise it will perform
a complete refresh.

69. what is snapshot log ?

It is a table that maintains a record of modifications to the master table in a snapshot. It is
stored in the same database as master table and is only available for simple snapshots. It
should be created before creating snapshots.

70. When will the data in the snapshot log be used ?

We must be able to create a after row trigger on table (i.e., it should be not be already
available )

After giving table privileges.

We cannot specify snapshot log name because oracle uses the name of the master table in
the name of the database objects that support its snapshot log.

The master table name should be less than or equal to 23 characters.

(The table name created will be MLOGS_tablename, and trigger name will be TLOGS
name).

72. What are the benefits of distributed options in databases ?

Database on other servers can be updated and those transactions can be grouped together
with others in a logical unit.
Database uses a two phase commit.

MANAGING BACKUP & RECOVERY

73. What are the different methods of backing up oracle database ?

- Logical Backups
- Cold Backups
- Hot Backups (Archive log)

74. What is a logical backup ?

Logical backup involves reading a set of databse records and writing them into a file.
Export utility is used for taking backup and Import utility is used to recover from backup.

75. What is cold backup ? What are the elements of it ?

Cold backup is taking backup of all physical files after normal shutdown of database. We
need to take.

- All Data files.
- All Control files.
- All on-line redo log files.
- The init.ora file (Optional)

76. What are the different kind of export backups ?

Full back – Complete database
Incremental – Only affected tables from last incremental date/full backup date.
Cumulative backup – Only affected table from the last cumulative date/full backup date.

77. What is hot backup and how it can be taken ?

Taking backup of archive log files when database is open. For this the ARCHIVELOG
mode should be enabled. The following files need to be backed up.

All data files.
All Archive log, redo log files.
On conrol file.

78. What is the use of FILE option in EXP command ?

To give the export file name.

79. What is the use of COMPRESS option in EXP command ?

Flag to indicate whether export should compress fragmented segments into single extents.

80. What is the use of GRANT option in EXP command ?

A flag to indicate whether grants on databse objects will be exported or not. Value is ‘Y’ or
‘N’.

81. What is the use of INDEXES option in EXP command ?

A flag to indicate whether indexes on tables will be exported.

82. What is the use of ROWS option in EXP command ?

Flag to indicate whether table rows should be exported. If ‘N’ only DDL statements for the
databse objects will be created.

83. What is the use of CONSTRAINTS option in EXP command ?

A flag to indicate whether constraints on table need to be exported.

84. What is the use of FULL option in EXP command ?

A flag to indicate whether full databse export should be performed.

85. What is the use of OWNER option in EXP command ?

List of table accounts should be exported.

86. What is the use of TABLES option in EXP command ?

List of tables should be exported.

87. What is the use of RECORD LENGTH option in EXP command ?

Record length in bytes.

88. What is the use of INCTYPE option in EXP command ?

Type export should be performed COMPLETE,CUMULATIVE,INCREMENTAL.

89. What is the use of RECORD option in EXP command ?

For Incremental exports, the flag indirects whether a record will be stores data dictionary
tables recording the export.

90. What is the use of PARFILE option in EXP command ?

Name of the parameter file to be passed for export.

91. What is the use of PARFILE option in EXP command ?

Name of the parameter file to be passed for export.

92. What is the use of ANALYSE ( Ver 7) option in EXP command ?

A flag to indicate whether statistical information about the exported objects should be
written to export dump file.

93. What is the use of CONSISTENT (Ver 7) option in EXP command ?

A flag to indicate whether a read consistent version of all the exported objects should be
maintained.

94. What is use of LOG (Ver 7) option in EXP command ?

The name of the file which log of the export will be written.

95.What is the use of FILE option in IMP command ?

The name of the file from which import should be performed.

96. What is the use of SHOW option in IMP command ?

A flag to indicate whether file content should be displayed or not.

97. What is the use of IGNORE option in IMP command ?

A flag to indicate whether the import should ignore errors encounter when issuing CREATE
commands.

98. What is the use of GRANT option in IMP command ?

A flag to indicate whether grants on database objects will be imported.

99. What is the use of INDEXES option in IMP command ?

A flag to indicate whether import should import index on tables or not.

100. What is the use of ROWS option in IMP command ?

A flag to indicate whether rows should be imported. If this is set to ‘N’ then only DDL for
database objects will be exectued.
SQL PLUS

STATEMENTS

1. What are the types of SQL Statement ?

Data Definition Language : CREATE,ALTER,DROP,TRUNCATE,REVOKE,NO
AUDIT & COMMIT.
Data Manipulation Language : INSERT,UPDATE,DELETE,LOCK TABLE,EXPLAIN
PLAN & SELECT.
Transactional Control : COMMIT & ROLLBACK
Session Control : ALTERSESSION & SET ROLE
System Control : ALTER SYSTEM.

2. What is a transaction ?

Transaction is logical unit between two commits and commit and rollback.

3. What is difference between TRUNCATE & DELETE ?

TRUNCATE commits after deleting entire table i.e., can not be rolled back.
Database triggers do not fire on TRUNCATE

DELETE allows the filtered deletion. Deleted records can be rolled back or committed.
Database triggers fire on DELETE.

4. What is a join ? Explain the different types of joins ?

Join is a query which retrieves related columns or rows from multiple tables.

Self Join – Joining the table with itself.
Equi Join – Joining two tables by equating two common columns.
Non-Equi Join – Joining two tables by equating two common columns.
Outer Join – Joining two tables in such a way that query can also retrive rows that do not have corresponding join value in the other table.

5. What is the Subquery ?

Subquery is a query whose return values are used in filtering conditions of the main query.

6. What is correlated sub-query ?

Correlated sub_query is a sub_query which has reference to the main query.

7. Explain Connect by Prior ?

Retrives rows in hierarchical order.
e.g. select empno, ename from emp where.

8. Difference between SUBSTR and INSTR ?

INSTR (String1,String2(n,(m)),
INSTR returns the position of the mth occurrence of the string 2 in string1. The search begins from nth position of string1.

SUBSTR (String1 n,m)
SUBSTR returns a character string of size m in string1, starting from nth postion of string1.

9. Explain UNION,MINUS,UNION ALL, INTERSECT ?

INTERSECT returns all distinct rows selected by both queries.
MINUS – returns all distinct rows selected by the first query but not by the second.
UNION – returns all distinct rows selected by either query
UNION ALL – returns all rows selected by either query,including all duplicates.

10. What is ROWID ?

ROWID is a pseudo column attached to each row of a table. It is 18 character long, blockno, rownumber are the components of ROWID.

11. What is the fastest way of accessing a row in a table ?

Using ROWID.

CONSTRAINTS

12. What is an Integrity Constraint ?

Integrity constraint is a rule that restricts values to a column in a table.

13. What is Referential Integrity ?

Maintaining data integrity through a set of rules that restrict the values of one or more columns of the tables based on the values of primary key or unique key of the referenced table.

14. What are the usage of SAVEPOINTS ?

SAVEPOINTS are used to subdivide a transaction into smaller parts. It enables rolling back part of a transaction. Maximum of five save points are allowed.

15. What is ON DELETE CASCADE ?

When ON DELETE CASCADE is specified ORACLE maintains referential integrity by automatically removing dependent foreign key values if a referenced primary or unique key value is removed.

16. What are the data types allowed in a table ?

CHAR,VARCHAR2,NUMBER,DATE,RAW,LONG and LONG RAW.

17. What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?

CHAR pads blank spaces to the maximum length. VARCHAR2 does not pad blank spaces. For CHAR it is 255 and 2000 for VARCHAR2.

18. How many LONG columns are allowed in a table ? Is it possible to use LONG columns in WHERE clause or ORDER BY ?

Only one LONG columns is allowed. It is not possible to use LONG column in WHERE or ORDER BY clause.

19. What are the pre requisites ?
I. to modify datatype of a column ?
ii. to add a column with NOT NULL constraint ?

To Modify the datatype of a column the column must be empty.
To add a column with NOT NULL constrain, the table must be empty.

20. Where the integrity constrints are stored in Data Dictionary ?

The integrity constraints are stored in USER_CONSTRAINTS.

21. How will you a activate/deactivate integrity constraints ?

The integrity constraints can be enabled or disabled by ALTER TABLE ENABLE constraint/DISABLE constraint.

22. If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?

It won’t, Because SYSDATE format contains time attached with it.

23. What is a database link ?

Database Link is a named path through which a remote database can be accessed.

24. How to access the current value and next value from a sequence ? Is it possible to access the current value in a session before accessing next value ?

Sequence name CURRVAL, Sequence name NEXTVAL.

It is not possible. Only if you access next value in the session, current value can be accessed.

25. What is CYCLE/NO CYCLE in a Sequence ?

CYCLE specifies that the sequence continues to generate values after reaching either maximum or minimum value. After pan ascending sequence reaches its maximum value, it generates its minimum value. After a descending sequence reaches its minimum, it generates its maximum.

NO CYCLE specifies that the sequence cannot generate more values after reaching its maximum or minimum value.

26. What are the advantages of VIEW ?

To protect some of the columns of a table from other users.
To hide complexity of a query.
To hide complexity of calculations.

27. Can a view be updated/inserted/deleted? If Yes under what conditions ?

A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.

28. If a View on a single base table is manipulated will the changes be reflected on the base table ?

If changes are made to the tables which are base tables of a view will the changes be reference on the view.

PL/SQL

Basiscs of PL/SQL

1. What is PL/SQL ?

PL/SQL is a procedural language that has both interactive SQL and procedural
programming language constructs such as iteration, conditional branching.

2. What is the basic structure of PL/SQL ?

PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks
can be used in PL/SQL.

3. What are the components of a PL/SQL block ?

A set of related declarations and procedural statements is called block.

4. What are the components of a PL/SQL Block ?

Declarative part, Executable part and Execption part.

Datatypes PL/SQL

5. What are the datatypes a available in PL/SQL ?

Some scalar data types such as
NUMBER,VARCHAR2,DATE,CHAR,LONG,BOOLEAN.
Some composite data types such as RECORD & TABLE.

6. What are % TYPE and % ROWTYPE ? What are the advantages of using these
over datatypes?

% TYPE provides the data type of a variable or a database column to that variable.

% ROWTYPE provides the record type that represents a entire row of a table or view or
columns selected in the cursor.

The advantages are : I. Need not know about variable’s data type
ii. If the database definition of a column in a table changes, the data type of a variable
changes accordingly.

7. What is difference between % ROWTYPE and TYPE RECORD ?

% ROWTYPE is to be used whenever query returns a entire row of a table or view.

TYPE rec RECORD is to be used whenever query returns columns of different table or
views and variables.

E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type );
e_rec emp% ROWTYPE
cursor c1 is select empno,deptno from emp;
e_rec c1 %ROWTYPE.

8. What is PL/SQL table ?

Objects of type TABLE are called “PL/SQL tables”, which are modelled as (but not the
same as) database tables, PL/SQL tables use a primary PL/SQL tables can have one
column and a primary key.

Cursors

9. What is a cursor ? Why Cursor is required ?

Cursor is a named private SQL area from where information can be accessed.
Cursors are required to process rows individually for queries returning multiple rows.

10. Explain the two type of Cursors ?

There are two types of cursors, Implict Cursor and Explicit Cursor.
PL/SQL uses Implict Cursors for queries.
User defined cursors are called Explicit Cursors. They can be declared and used.

11. What are the PL/SQL Statements used in cursor processing ?

DECLARE CURSOR cursor name, OPEN cursor name, FETCH cursor name INTO
<variable list> or Record types, CLOSE cursor name.

12. What are the cursor attributes used in PL/SQL ?

%ISOPEN – to check whether cursor is open or not
% ROWCOUNT – number of rows featched/updated/deleted.
% FOUND – to check whether cursor has fetched any row. True if rows are featched.
% NOT FOUND – to check whether cursor has featched any row. True if no rows are
featched.
These attributes are proceded with SQL for Implict Cursors and with Cursor name for
Explict Cursors.

13. What is a cursor for loop ?

Cursor for loop implicitly declares %ROWTYPE as loop index,opens a cursor, fetches
rows of values from active set into fields in the record and closes when all the records have
been processed.

eg. FOR emp_rec IN C1 LOOP
salary_total := salary_total +emp_rec sal;
END LOOP;

14. What will happen after commit statement ?
Cursor C1 is
Select empno,
ename from emp;
Begin
open C1;
loop
Fetch C1 into
eno.ename;
Exit When
C1 %notfound;—–
commit;
end loop;
end;

The cursor having query as SELECT …. FOR UPDATE gets closed after
COMMIT/ROLLBACK.

The cursor having query as SELECT…. does not get closed even after
COMMIT/ROLLBACK.

15. Explain the usage of WHERE CURRENT OF clause in cursors ?

WHERE CURRENT OF clause in an UPDATE,DELETE statement refers to the latest
row fetched from a cursor.

Database Triggers

16. What is a database trigger ? Name some usages of database trigger ?

Database trigger is stored PL/SQL program unit associated with a specific database table.
Usages are Audit data modificateions, Log events transparently, Enforce complex business
rules Derive column values automatically, Implement complex security authorizations.
Maintain replicate tables.

17. How many types of database triggers can be specified on a table ? What are they
?

Insert Update Delete

Before Row o.k. o.k. o.k.

After Row o.k. o.k. o.k.

Before Statement o.k. o.k. o.k.

After Statement o.k. o.k. o.k.

If FOR EACH ROW clause is specified, then the trigger for each Row affected by the
statement.

If WHEN clause is specified, the trigger fires according to the retruned boolean value.

18. Is it possible to use Transaction control Statements such a ROLLBACK or
COMMIT in Database Trigger ? Why ?

It is not possible. As triggers are defined for each table, if you use COMMIT of
ROLLBACK in a trigger, it affects logical transaction processing.

19. What are two virtual tables available during database trigger execution ?

The table columns are referred as OLD.column_name and NEW.column_name.
For triggers related to INSERT only NEW.column_name values only available.
For triggers related to UPDATE only OLD.column_name NEW.column_name values only
available.
For triggers related to DELETE only OLD.column_name values only available.

20. What happens if a procedure that updates a column of table X is called in a
database trigger of the same table ?

Mutation of table occurs.

21. Write the order of precedence for validation of a column in a table ?

I. done using Database triggers.
ii. done using Integarity Constraints.

I & ii.

Exception :

22. What is an Exception ? What are types of Exception ?

Exception is the error handling part of PL/SQL block. The types are Predefined and
user_defined. Some of Predefined execptions are.

CURSOR_ALREADY_OPEN
DUP_VAL_ON_INDEX
NO_DATA_FOUND
TOO_MANY_ROWS
INVALID_CURSOR
INVALID_NUMBER
LOGON_DENIED
NOT_LOGGED_ON
PROGRAM-ERROR
STORAGE_ERROR
TIMEOUT_ON_RESOURCE
VALUE_ERROR
ZERO_DIVIDE
OTHERS.

23. What is Pragma EXECPTION_INIT ? Explain the usage ?

The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an
oracle error. To get an error message of a specific oracle error.

e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)

24. What is Raise_application_error ?

Raise_application_error is a procedure of package DBMS_STANDARD which allows to
issue an user_defined error messages from stored sub-program or database trigger.

25. What are the return values of functions SQLCODE and SQLERRM ?

SQLCODE returns the latest code of the error that has occured.
SQLERRM returns the relevant error message of the SQLCODE.

26. Where the Pre_defined_exceptions are stored ?

In the standard package.

Procedures, Functions & Packages ;

27. What is a stored procedure ?

A stored procedure is a sequence of statements that perform specific function.

28. What is difference between a PROCEDURE & FUNCTION ?

A FUNCTION is always returns a value using the return statement.
A PROCEDURE may return one or more values through parameters or may not
Return at all.

29. What are advantages of Stored Procedures /

Extensibility, Modularity, Reusability, Maintainability and one time compilation.

30. What are the modes of parameters that can be passed to a procedure ?

IN,OUT,IN-OUT parameters.

31. What are the two parts of a procedure ?

Procedure Specification and Procedure Body.

32. Give the structure of the procedure ?

PROCEDURE name (parameter list…..)
is
local variable declarations

BEGIN
Executable statements.
Exception.
exception handlers

end;

33. Give the structure of the function ?

FUNCTION name (argument list …..) Return datatype is
local variable declarations
Begin
executable statements
Exception
execution handlers
End;

34. Explain how procedures and functions are called in a PL/SQL block ?

Function is called as part of an expression.
sal := calculate_sal (‘a822′);
procedure is called as a PL/SQL statement
calculate_bonus (‘A822′);

35. What is Overloading of procedures ?

The Same procedure name is repeated with parameters of different datatypes and
parameters in different positions, varying number of parameters is called overloading of
procedures.

e.g. DBMS_OUTPUT put_line

36. What is a package ? What are the advantages of packages ?

Package is a database object that groups logically related procedures.
The advantages of packages are Modularity, Easier Applicaton Design, Information.
Hiding,. reusability and Better Performance.

37.What are two parts of package ?

The two parts of package are PACKAGE SPECIFICATION & PACKAGE BODY.

Package Specification contains declarations that are global to the packages and local to the
schema.
Package Body contains actual procedures and local declaration of the procedures and
cursor declarations.

38. What is difference between a Cursor declared in a procedure and Cursor
declared in a package specification ?

A cursor declared in a package specification is global and can be accessed by other
procedures or procedures in a package.
A cursor declared in a procedure is local to the procedure that can not be accessed by
other procedures.

39. How packaged procedures and functions are called from the following ?
a. Stored procedure or anonymous block
b. an application program such a PRC *C, PRO* COBOL
c. SQL *PLUS

a. PACKAGE NAME.PROCEDURE NAME (parameters);
variable := PACKAGE NAME.FUNCTION NAME (arguments);
EXEC SQL EXECUTE
b.
BEGIN
PACKAGE NAME.PROCEDURE NAME (parameters)
variable := PACKAGE NAME.FUNCTION NAME (arguments);
END;
END EXEC;
c. EXECUTE PACKAGE NAME.PROCEDURE if the procedures does not have any
out/in-out parameters. A function can not be called.

40. Name the tables where characteristics of Package, procedure and functions are
stored ?

User_objects, User_Source and User_error.

1. To see current user name
Sql> show user;
2. Change SQL prompt name
SQL> set sqlprompt ?Manimara > ?
Manimara >
Manimara >
3. Switch to DOS prompt
SQL> host
4. How do I eliminate the duplicate rows ?
SQL> delete from table_name where rowid not in (select max(rowid) from table group by duplicate_values_field_name);
or
SQL> delete duplicate_values_field_name dv from table_name ta where rowid <(select min(rowid) from table_name tb where ta.dv=tb.dv);
Example.
Table Emp
Empno Ename
101 Scott
102 Jiyo
103 Millor
104 Jiyo
105 Smith
delete ename from emp a where rowid < ( select min(rowid) from emp b where a.ename = b.ename);
The output like,
Empno Ename
101 Scott
102 Millor
103 Jiyo
104 Smith
5. How do I display row number with records?
To achive this use rownum pseudocolumn with query, like SQL> SQL> select rownum, ename from emp;
Output:
1 Scott
2 Millor
3 Jiyo
4 Smith
6. Display the records between two range
select rownum, empno, ename from emp where rowid in
(select rowid from emp where rownum <=&upto
minus
select rowid from emp where rownum<&Start);
Enter value for upto: 10
Enter value for Start: 7
ROWNUM EMPNO ENAME
——— ——— ———-
1 7782 CLARK
2 7788 SCOTT
3 7839 KING
4 7844 TURNER
7. I know the nvl function only allows the same data type(ie. number or char or date Nvl(comm, 0)), if commission is null then the text ?Not Applicable? want to display, instead of blank space. How do I write the query?
SQL> select nvl(to_char(comm.),’NA’) from emp;
Output :
NVL(TO_CHAR(COMM),’NA’)
———————–
NA
300
500
NA
1400
NA
NA
8. Oracle cursor : Implicit & Explicit cursors
Oracle uses work areas called private SQL areas to create SQL statements.
PL/SQL construct to identify each and every work are used, is called as Cursor.
For SQL queries returning a single row, PL/SQL declares all implicit cursors.
For queries that returning more than one row, the cursor needs to be explicitly declared.
9. Explicit Cursor attributes
There are four cursor attributes used in Oracle
cursor_name%Found, cursor_name%NOTFOUND, cursor_name%ROWCOUNT, cursor_name%ISOPEN
10. Implicit Cursor attributes
Same as explicit cursor but prefixed by the word SQL
SQL%Found, SQL%NOTFOUND, SQL%ROWCOUNT, SQL%ISOPEN
Tips : 1. Here SQL%ISOPEN is false, because oracle automatically closed the implicit cursor after executing SQL statements.
: 2. All are Boolean attributes.
11. Find out nth highest salary from emp table
SELECT DISTINCT (a.sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.sal)) FROM EMP B WHERE a.sal<=b.sal);
Enter value for n: 2
SAL
———
3700
12. To view installed Oracle version information
SQL> select banner from v$version;
13. Display the number value in Words
SQL> select sal, (to_char(to_date(sal,’j'), ‘jsp’))
from emp;
the output like,
SAL (TO_CHAR(TO_DATE(SAL,’J'),’JSP’))
——— —————————————————–
800 eight hundred
1600 one thousand six hundred
1250 one thousand two hundred fifty
If you want to add some text like,
Rs. Three Thousand only.
SQL> select sal “Salary “,
(‘ Rs. ‘|| (to_char(to_date(sal,’j'), ‘Jsp’))|| ‘ only.’))
“Sal in Words” from emp
/
Salary Sal in Words
——- ——————————————————
800 Rs. Eight Hundred only.
1600 Rs. One Thousand Six Hundred only.
1250 Rs. One Thousand Two Hundred Fifty only.
14. Display Odd/ Even number of records
Odd number of records:
select * from emp where (rowid,1) in (select rowid, mod(rownum,2) from emp);
1
3
5
Even number of records:
select * from emp where (rowid,0) in (select rowid, mod(rownum,2) from emp)
2
4
6
15. Which date function returns number value?
months_between
16. Any three PL/SQL Exceptions?
Too_many_rows, No_Data_Found, Value_Error, Zero_Error, Others
17. What are PL/SQL Cursor Exceptions?
Cursor_Already_Open, Invalid_Cursor
18. Other way to replace query result null value with a text
SQL> Set NULL ?N/A?
to reset SQL> Set NULL ??
19. What are the more common pseudo-columns?
SYSDATE, USER , UID, CURVAL, NEXTVAL, ROWID, ROWNUM
20. What is the output of SIGN function?
1 for positive value,
0 for Zero,
-1 for Negative value.
21. What is the maximum number of triggers, can apply to a single table?
12 triggers

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Create Database Manuly on Oracle 10g

Posted on 20. Feb, 2008 by sabin.

1. Create necessary directories

mkdir D:\oracle\product\10.2.0\admin\arcl\adump
mkdir D:\oracle\product\10.2.0\admin\arcl\bdump
mkdir D:\oracle\product\10.2.0\admin\arcl\cdump
mkdir D:\oracle\product\10.2.0\admin\arcl\dpdump
mkdir D:\oracle\product\10.2.0\admin\arcl\pfile
mkdir D:\oracle\product\10.2.0\admin\arcl\udump
mkdir D:\oracle\product\10.2.0\db_1\cfgtoollogs\dbca\arcl
mkdir D:\oracle\product\10.2.0\db_1\database
mkdir D:\oracle\product\10.2.0\flash_recovery_area
mkdir D:\oracle\product\10.2.0\oradata\arcl

2. Make necessary files

2.1. first make pfile and save it at the location

D:\oracle\product\10.2.0\db_1\database

2.2. then make password file using following cmd
orapwd file=D:\oracle\product\10.2.0\db_1\database\PWDarcl.ora password=<password> force=y

3. Then set SID using following command
set ORACLE_SID=<SID_Name>

4. Create services using following command
oradim -new -sid <sidname> manual -spfile
oradim -edit -sid TRYDB -startmode auto -srvcstart system

5. Now start and login to sql
sqlplus
/ as sysdba
startup nomount pfile=”D:\oracle\product\10.2.0\admin\arcl\scripts\init.ora”;

6. Then create database using following command
set echo on
spool D:\oracle\product\10.2.0\admin\arcl\scripts\CreateDB.log
startup nomount pfile=”D:\oracle\product\10.2.0\admin\arcl\scripts\init.ora”;
CREATE DATABASE “arcl”
MAXINSTANCES 8
MAXLOGHISTORY 1
MAXLOGFILES 16
MAXLOGMEMBERS 3
MAXDATAFILES 100
DATAFILE ‘C:\oracle\product\10.2.0\oradata\arcl\system01.dbf’ SIZE 300M REUSE     AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED
EXTENT MANAGEMENT LOCAL
SYSAUX DATAFILE ‘D:\oracle\product\10.2.0\oradata\arcl\sysaux01.dbf’ SIZE 120M REUSE     AUTOEXTEND ON NEXT 10240K MAXSIZE UNLIMITED
SMALLFILE DEFAULT TEMPORARY TABLESPACE TEMP TEMPFILE     ‘D:\oracle\product\10.2.0\oradata\arcl\temp01.dbf’ SIZE 20M REUSE AUTOEXTEND ON NEXT     640K MAXSIZE UNLIMITED
SMALLFILE UNDO TABLESPACE “UNDOTBS1″ DATAFILE     ‘D:\oracle\product\10.2.0\oradata\arcl\undotbs01.dbf’ SIZE 200M REUSE AUTOEXTEND ON     NEXT 5120K MAXSIZE UNLIMITED
CHARACTER SET WE8MSWIN1252
NATIONAL CHARACTER SET AL16UTF16
LOGFILE GROUP 1 (‘D:\oracle\product\10.2.0\oradata\arcl\redo01.log’) SIZE 51200K,
GROUP 2 (‘D:\oracle\product\10.2.0\oradata\arcl\redo02.log’) SIZE 51200K,
GROUP 3 (‘D:\oracle\product\10.2.0\oradata\arcl\redo03.log’) SIZE 51200K
USER SYS IDENTIFIED BY “&&sysPassword” USER SYSTEM IDENTIFIED BY “&&systemPassword”;
spool off

7. Then create user table for the newly created database using following command
set echo on
spool D:\oracle\product\10.2.0\admin\arcl\scripts\CreateDBFiles.log
CREATE SMALLFILE TABLESPACE “USERS” LOGGING DATAFILE ‘D:\oracle\product\10.2.0\oradata\arcl\users01.dbf’ SIZE 5M REUSE AUTOEXTEND ON NEXT 1280K MAXSIZE UNLIMITED EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;
ALTER DATABASE DEFAULT TABLESPACE “USERS”;
spool off

8. Then run the following scripts to create system tables,views,functions,procedures and authorities
set echo on
spool D:\oracle\product\10.2.0\admin\arcl\scripts\CreateDBCatalog.log
@D:\oracle\product\10.2.0\db_1\rdbms\admin\catalog.sql;
@D:\oracle\product\10.2.0\db_1\rdbms\admin\catblock.sql;
@D:\oracle\product\10.2.0\db_1\rdbms\admin\catproc.sql;
@D:\oracle\product\10.2.0\db_1\rdbms\admin\catoctk.sql;
@D:\oracle\product\10.2.0\db_1\rdbms\admin\owminst.plb;
@D:\oracle\product\10.2.0\db_1\sqlplus\admin\pupbld.sql;
set echo on
spool D:\oracle\product\10.2.0\admin\arcl\scripts\sqlPlusHelp.log
@D:\oracle\product\10.2.0\db_1\sqlplus\admin\help\hlpbld.sql helpus.sql;
spool off
spool off

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Using Global/Distributed Transactions in Java/JDBC with Oracle Real Application Clusters

Posted on 18. Feb, 2008 by sabin.

This document describes some of the ways to leverage the high availability features of Oracle Real Application Cluster (RAC) databases by moving the load balancing functionality from the Oracle server/Oracle driver to your application. In this article, I discuss the ways to achieve load balancing of connections across RAC nodes and yet maintain the sticky nature to the same RAC node for the all of the participants of a single global transaction. I have used Java examples wherever possible, but most of the programming constructs can be mapped to other sufficiently advanced programming languages.

An Oracle Real Application Cluster database is a clustered database. A cluster is a group of independent servers that cooperate as a single system. Clusters provide improved fault resilience and modular incremental system growth over single, symmetrical multiprocessor systems. Oracle’s RAC page has more information on RAC technology.

A global transaction is a mechanism that allows a set of programming tasks, potentially using more than one resource manager and potentially executing on multiple servers, to be treated as one logical unit. Once a process is in transaction mode, any service requests made to servers may be processed on behalf of the current transaction. The services that are called and join the transaction are referred to as transaction participants. The value returned by a participant may affect the outcome of the transaction. A global transaction may be composed of several local transactions, each accessing the same resource manager. The resource manager is responsible for performing concurrency control and atomicity of updates.

Problems with Global Transactions and Oracle RAC

Problems occur when connections participating in a distributed transaction are routed to different instances of an RAC cluster. A split transaction is a distributed transaction that spans more than one instance of an RAC database. This implies that different branches of the same distributed transaction are located on different instances of an RAC database. This could result in erroneous situations, as follows:

During normal operation: Neither branch can see changes made by the other branch. This can cause row-level lock conflicts amongst these branches, leading to ORA-2049 errors (timeout waiting for distributed lock).
During recovery operation: Failures can occur during two-phase commit (2PC). Sometimes 2PC requires its own connection to the database (e.g., an abort). In such cases, a 2PC operation may be attempted on a transaction branch at an instance where that branch does not exist, causing missing transaction errors (ORA-24756). This in turn leaves the branch hanging as an active branch to be cleaned up by the Process Monitor daemon (PMON). While the branch is active, it still holds row-level locks on all rows that it modified. Similarly, if the 2PC operation that failed is a commit, then in-doubt transactions can remain in the database. This can cause ORA-1591 errors when another transaction attempts to access data that has been modified by the in-doubt transaction. You can find more detailed explanation of this problem in Oracle’s “Best Practices for using XA with RAC” (PDF, 219 KB).

Recommended Approach

The following design forms the foundation of the recommended approach:

Create multiple pools, one for each RAC node in the cluster. I call each pool a node pool. For example, if you have three RAC nodes, create three node pools. All popular pooling components and application servers support creating multiple pools.
Disable server-side load balancing for each of the pools. Setting the INSTANCE_NAME attribute in your JDBC connect descriptor aliases will disable server-side load balancing. For example:
```
  jdbc:oracle:thin:@(DESCRIPTION=
    (ADDRESS_LIST=
      (ADDRESS=(PROTOCOL=tcp)(HOST=MYDBHOST1)(PORT=1522))
    )
    (CONNECT_DATA=
      (SERVICE_NAME=MYDB)(INSTANCE_NAME=MYDB1)
    )
  )
```
If you miss the INSTANCE_NAME attribute in your JDBC connect descriptor, the Oracle TNS Listener could still redirect the connection request to some other instance, depending on the load on the instance in question.
Write a connection factory that does the following when a connection is requested:
- Checks if a node pool is already associated with the thread.
- If a node pool is not associated with the thread, randomly picks a pool from the available pools and associates the node pool with the thread.
- If a pool is associated with the thread, just reuses the pool.
- Depending on your application behavior (discussed later), disassociates the pool from the thread.

Multithreaded Application

In a multithreaded application, multiple threads are spawned to perform concurrent tasks. Usually global transactions have thread affinity; i.e., they are identified and associated by the threads in which they run. All connections participating in the same global transaction must be drawn from the pool or a data source in the same thread. You can maintain affinity to a node pool by associating the thread with the node pool. The connection factory responsible for providing the connection should then inspect the thread and reuse the node pool referenced in the thread space. The connection factory is allowed to randomly pick a pool only if there is no node pool associated with the thread. You can implement this in Java using the ThreadLocal class. When the connection factory requests a connection, it inspects the thread space to check if a node pool is associated with the thread; if there is, it reuses it. Otherwise, it randomly picks one.

/*
 * Method ConnectionFactory.getConnection
 */
Connection getConnection() {

  // nodePoolTracker is a ThreadLocal object
  // defined in the class definition
  NodePoolIndentifier poolId =
    (NodePoolIndentifier) nodePoolTracker.get();
  if (poolId == null) {
    // There is no node pool associated with
    // this thread, randomly pick
    // one and store it in the thread
    NodePool pool = getLeastLoadedInstacePool();
    nodePoolTracker.set(
      new NodePoolIdentifier(pool.getId());
    return pool.getConnection();
  }
  else {
    // get a reference to the pool
    NodePool pool = getPoolById(poolId);
    return pool.getConnection();
  }

The above method creates an affinity between the thread and the node pool. If your application spawns a new thread for every new task, you don’t need to manually clean up the thread space. However, for applications that have thread pools or reuse threads (like web servers, app servers, etc.), you need to manually clean up the thread space after each global transaction or task completion. This entirely depends on how you manage threads in your application. If you don’t clean up the thread space, the node pool will get associated with the thread for the complete lifespan of the thread, which may result in suboptimal load balancing across RAC instances.

Web Application

Modern web applications have a distinct advantage over standalone applications. They run in a managed environment which delegates most of the dirty work to the underlying application/web server. Here you can leverage an approach similar to standalone applications–using a thread pool–but by using HTTP filters, you can eliminate the problem with reusable threads by resetting the state of the thread in the HTTP filters.

You can do this using Java servlets as follows:

Configure custom servlet filters to intercept requests and responses from your applications.
Pick a node pool and set it in the ThreadLocal object in the in-filter before the request is sent to the actual request handler.
After the request handler processes the request (in the out filter), reset the thread state.

All of the connections for a particular request are directed to a single RAC instance. Alternatively, you can also use the request object to store the reference of the node pool rather then the ThreadLocal object. The downside of this approach is that you need to pass the request object to all of the components that draw a connection to the database.

Known Issues

This approach assumes a specific pattern in the life span of global transactions that happens to work with most popular applications. Some places where this would not work include:

Global transactions spanning multiple threads.
Multithreaded application reusing threads: this is kind of tricky, though not very dangerous. In this case, the node pool (RAC node) gets tightly coupled to the thread for the complete lifespan of the thread. You can still work around this problem depending on your application. For example, in a web server, you can have the request filters reset the thread state after each request. You will have to figure out your application-specific logic to reset the thread state after the thread has processed each request.
What happens if an RAC node goes down while the corresponding node pool is being used by some threads? I would still prefer to let the complete global transaction roll back and report the operation as a failed operation.

http://www.oracle.com/technology/products/database/clustering/pdf/TWP_RAC10gR2.pdf

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/ThreadLocal.html

http://www.oracle.com/technology/products/database/clustering/pdf/bestpracticesforxaandrac.pdf

http://www.oracle.com/database/rac_home.html

http://smartpool.sourceforge.net/

package pooling;

import java.sql.*;
import java.util.HashMap;

/**
 * This class demonstrates the use of ThreadLocal to pin a particular connection to a RAC node.
 *
 */
public class RACConnectionFactory {

    /**
     * Instance connect descriptors to the database
     */
    private static final String url1 = "jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=MYHOST1)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=DEV)(INSTANCE_NAME=DEV1)))";
    private static final String url2 = "jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=MYHOST2)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=DEV)(INSTANCE_NAME=DEV2)))";

    /**
     * Store the list of connections, ideally should store references to node pools
     */
    private HashMap poolMap = new HashMap();

    /**
     * Simple algo to keep track of which node is least used
     */
    private String lastNodePoolUsed = null;

    /**
     * Singleton pattern
     */
    private static RACConnectionFactory singletonFactory = null;

    private static boolean isDebug = true;

    /*
     *  Our Golden Horse, Thread local.
     */

    private static ThreadLocal nodePoolTracker = new ThreadLocal();

    /**
     * Easy method for logging
     */
    private static void log(String log) {
        if (isDebug) {
            System.out.println(log);
            System.out.flush();
        }
    }

    /**
     * Gets the instance name from the V$instance view, the connected user should have the required prevelige
     * @param conn
     * @return
     * @throws Exception
     */
    private String getInstanceName(Connection conn) throws Exception {
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            stmt  = conn.prepareStatement("select instance_name from v$instance");
            rs = stmt.executeQuery();
            if (rs.next()) {
                return rs.getString(1);
            }
            else {
                throw new Exception("No Rows found, should never happen");
            }
        }
        finally {
            stmt.close();
            rs.close();
        }
    }

    /**
     * Gets a connection from the database
     * @param url
     * @return
     * @throws Exception
     */

    private Connection getRawConnection(String url) throws Exception {
        Class.forName("oracle.jdbc.driver.OracleDriver");
        return DriverManager.getConnection(url, "sachin", "sachin");
    }

    /**
     * Just returns the last not used pool
     * @return
     */
    private String getLeastLoadedPool() {
        if (lastNodePoolUsed == null) {
            lastNodePoolUsed = "1";
            return "1";
        }
        if (lastNodePoolUsed.equals("1")) {
            lastNodePoolUsed = "2";
            return "2";
        }
        else {
            lastNodePoolUsed = "1";
            return "1";
        }
    }

    private Connection getConnection(String poolId) {
        return (Connection)poolMap.get(poolId);
    }

    private RACConnectionFactory() throws Exception {

        Connection conn = getRawConnection(url1);
        // Validate that this connection is indeed gone to DEV1
        if (!(getInstanceName(conn).equalsIgnoreCase("DEV1"))) {
            throw new Exception("This was supposed to hit DEV1, actual: " + getInstanceName(conn));
        }

        // Not creating any pools, assume pools are of size 1 
        poolMap.put("1", conn);

        conn = getRawConnection(url2);
        // Validate that this connection is indeed gone to DEV2
        if (!(getInstanceName(conn).equalsIgnoreCase("DEV2"))) {
            throw new Exception("This was supposed to hit DEV2, actual: " + getInstanceName(conn));
        }
        poolMap.put("2", conn);

    }

    /**
     * This method does all the work of getting the connection, sticking the poolid in to the thread ....
     * @return
     * @throws Exception
     */

    public synchronized static Connection getConnection() throws Exception {

        if (singletonFactory == null)
            singletonFactory = new RACConnectionFactory();

        String poolId = (String) nodePoolTracker.get();
        if (poolId == null) {
        // one and store it in the thread
            poolId = singletonFactory.getLeastLoadedPool();
            nodePoolTracker.set(poolId);
            log("No Pool Associated:" + Thread.currentThread().getId() + ", adding: " + poolId);
            return singletonFactory.getConnection(poolId);
        }
        else {
            log("Pool Associated:" + Thread.currentThread().getId() + ", " + poolId);
            return singletonFactory.getConnection(poolId);
        }

    }

    public static void main (String args[] ) throws Exception {

        log("main thread is: " +  Thread.currentThread().getId());
        TaskProcessor taskProcessor[] = new TaskProcessor[5];
        Thread threads[] = new Thread[taskProcessor.length];
        for (int i=0; i<taskProcessor.length; i++) {
            taskProcessor[i] = new TaskProcessor(i);
            threads[i] = new Thread(taskProcessor[i]);
            threads[i].start();
        }
        for (int i=0; i<taskProcessor.length; i++) {
            if (threads[i].isAlive()) {
                threads[i].join();
            }
        }

    }

    /**
     * Thread to run many concurrent connections
     */
    private static class TaskProcessor implements Runnable {

        private int number = 0;

        public TaskProcessor(int number) {
            this.number = number;
        }

        public void run() {

            try {

                log("Thread started: " + Thread.currentThread().getId());

                // Get a connection
                Connection conn = RACConnectionFactory.getConnection();

                // Sleep and yield so that other threads can run
                Thread.yield();
                //Thread.sleep(1000);
                Thread.yield();

                Connection conn1 = RACConnectionFactory.getConnection();

                log("Thread " + Thread.currentThread().getId() + ": First Con: " +  conn);
                log("Thread " + Thread.currentThread().getId() + ": Second Con: " +  conn1);

                //ideally we should be checking if both the connections have come from the same pool, but since this
                // is just a mockup and we are running a single connection pool, we will directly check if the connections are same references.
                if (conn1 != conn)
                    throw new Exception("Connections dont match: " + conn + ": " + conn1);

                log("Thread " + Thread.currentThread().getId() + " over");

            } catch (Exception e) {
                throw new RuntimeException(e);
            }

        }

    }

}

Assuming a 2 node Oracle RAC cluster , Give the connect url as

jdbc:oracle:thin:@
(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = host1-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = host2-vip)(PORT = 1521))
(LOAD_BALANCE = yes)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = db-service)
(FAILOVER_MODE =(TYPE = SELECT)(METHOD = BASIC)(RETRIES = 180)(DELAY = 5))
)
)

where host1-vip is virtual IP of node1
host2-vip is virtual IP of node2
db_service is the Service name of the database

Oracle Database Programming using Java and Web Services

http://db360.blogspot.com/2007/01/is-your-java-application-failoverproof.html

http://www.oracle.com/technology/tech/java/sqlj_jdbc/index.html

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Oracle ora 24242 error

Posted on 18. Feb, 2008 by sabin.

http://broersa.wordpress.com/   exec dbms_network_acl_admin.create_acl(acl => 'resolve.xml',description => 'resolve acl', principal => 'ABACUS', is_grant => true, privilege => 'resolve'); exec dbms_network_acl_admin.assign_acl(acl => 'resolve.xml', host => '*');    select  utl_inaddr.get_host_name('116.90.226.210') from dual; select  utl_inaddr.get_host_name('mail.abacusnepal.com') from dual;  select  utl_inaddr.get_host_name('127.0.0.1') from dual;       http://www.liberidu.com/blog/?p=246  DECLARE   acl_path  VARCHAR2(4000); BEGIN   SELECT acl INTO acl_path FROM dba_network_acls    WHERE host = 'host_name' AND lower_port IS NULL AND upper_port IS NULL; IF DBMS_NETWORK_ACL_ADMIN.CHECK_PRIVILEGE(acl_path,                                          'user_name','connect') IS NULL THEN     DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE(acl_path,                                          'user_name', TRUE, 'connect'); END IF; EXCEPTION   WHEN no_data_found THEN     DBMS_NETWORK_ACL_ADMIN.CREATE_ACL('ACL_name.xml',       'ACL description', 'user_name', TRUE, 'connect');     DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL('ACL_name.xml','host_name'); END; COMMIT;

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MySQL Installing and Giving Permission

Posted on 18. Feb, 2008 by sabin.

yum install mysql mysql-devel mysql-server

chkconfig –levels 235 mysqld on
/etc/init.d/mysqld start

netstat -tap | grep mysql

It should show a line like this:

[root@server1 named]# netstat -tap | grep mysql
tcp 0 0 *:mysql *:* LISTEN 2470/mysqld
[root@server1 named]#

mysqladmin -u root password yourrootsqlpassword
mysqladmin -h server1.example.com -u root password yourrootsqlpassword

GRANT ALL ON accounts.* TO ‘root’@'%’;

grant all privileges on accounts.* to root@localhost ;
$ mysql -u root

If a password is required, use the extra switch -p:

$ mysql -u root -p
Enter password:

Now that you are logged in, we create a database:

mysql> create database sabindb;
Query OK, 1 row affected (0.00 sec)

We allow user sabinuser to connect to the server from localhost using the
password sabinpasswd:

mysql> grant usage on *.* to sabinuser@localhost identified by
‘sabinpasswd’;
Query OK, 0 rows affected (0.00 sec)

And finally we grant all privileges on the sabin database to this user:

mysql> grant all privileges on sabindb.* to sabinuser@localhost ;
Query OK, 0 rows affected (0.00 sec)

And that’s it. You can now check that you can connect to the MySQL server
using this command:

$ mysql -u sabinuser -p’sabinpasswd’ sabindb
Your MySQL connection id is 12
Server version: 5.0.38-Ubuntu_0ubuntu1-log Ubuntu 7.04 distribution

Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.

mysql>

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Archive for 'Oracle'

RMAN BACKUP AND RECOVERY PRACTICE WITH RAC AND ASM

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My Oracle Notes

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Oracle Userfull scripts

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Oracle backup script for RAC clustering

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Oracle some scripts

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Oracle Concepts and Architecture Database Structures.

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Create Database Manuly on Oracle 10g

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Using Global/Distributed Transactions in Java/JDBC with Oracle Real Application Clusters

Problems with Global Transactions and Oracle RAC

Recommended Approach

Multithreaded Application

Web Application

Known Issues

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Oracle ora 24242 error

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MySQL Installing and Giving Permission

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