Thursday, May 31, 2012

Copy table data between Oracle databases on the fly without creating a database link

copy from user/pass@source to user/pass@dest create table_name using select * from table_name

this sqlplus command create a table in destination database and insert all tables data from source database

more infos

Shell script to move oracle datafile

# We set the SID of the oracle database

# We define the log filename

# shutdown the database before moving the files
echo "Shutting down the database ==> `date`" >> $logile

sqlplus "/ as sysdba" <<fin
shutdown immediate

echo "Base arretee... `date`"  >> $logfile

# Now we can move the files on OS level
echo "Moving datafiles..." >> $logfile

mv old_1 new_1
mv old_2 new_2
mv old_n new_n

# echo "We mount the database and rename the files on database level `date`" >> $logfile

sqlplus "/ as sysdba" <<eof




echo "fertig... `date`" >> $logfile

Steps to move Oracle datafiles to another file system

  • Take the tablespace offline
If you want to know in wich tablespace a datafile belong

select TABLESPACE_NAME from dba_data_files where FILE_NAME = 'file_name';

To take a tablespace offline

alter tablespace tablespace_name offline

  • Physicaly move the datafiles at OS level
mv 'old_file_name' 'new_file_name' (on Linux / Unix)

  • Rename the datafiles at database level
alter tablespace tablespace_name rename datafile 'old_datafile_name' to 'new_data_file_name';

  • Bring the tablespace back online
alter tablespace tablespace_name online;

Wednesday, May 30, 2012

ORA 29807 during Oracle database creation with DBCA

I am trying to create a database in oracle 9i with dbca utility, during the creation of data dictionary viewsoracle returns an error ORA-29807 "specified operator does not exist"

The Oracle oerr utility give this info about this error

$ oerr ORA 29807
"specified operator does not exist"
// *Cause: The operator which has been specified does not exist.
// *Action: Ensure that the operator that has been specified does exist.

according to the documentation about ORA-29807, "A patchset has been installed on the Oracle Server base release".

This document also states that you may simply ignore ORA-29807 as a fix.

Tuesday, May 29, 2012

How to efficiently allocate your Oracle database resources

What is the limit on the amount of resources a user can use? 
What if a user unwittingly starts a SQL program that guzzles resources like crazy and brings your system to its knees? 
How can ensure that the databases is not loaded down by inefficient queries.

Can you limit an individual's usage of resources, so you can allocate resources on a need-to-use basis? 

You can set the individual resource limits in Oracle by using what are known as profiles. 
You can use profiles to set hard limits on resource consumption by the various users in the database. Profiles help you limit the number of sessions a user can simultaneously keep open, the length of time these sessions can be maintained, and the usage of CPU and other resources. 

Here, for example, is a profile called "reporting" 

SQL> create profile reporting
  2  limit
  3  connect_time 120
  4  failed_login_attempts 2
  5  idle_time 60
  6* sessions_per_user 2;
Profile created.
The reporting profile when granted to a user will permit that user to be connected for a maximum of 120 seconds and will log out the user if he or she is idle for more than 1 minute. The user is limited to two sessions at any one time. If the user fails to log in within two attempts, the user's accounts will be "locked" for a specified period or until the DBA manually unlocks them.

Oracle9i enables you to set limits on several parameters within a profile. The following sections provide brief explanations of these parameters. You can divide the profile parameters into two broad types: resource parameters, which are concerned purely with limiting resource usage, and password parameters, which are used for enforcing password-related security policies.

Resource parameters are profile parameters that you can set to control resource usage by users. The main purpose in using resource parameters is to ensure that a single user or a set of users doesn't monopolize the database and server resources. Here are the most important resource parameters that you can set within an Oracle9i database:
  • Connect_time: The total time a session may remain connected to the database.
  • Cpu_per_call: Limits the CPU used per each call within a transaction (for the parse, execute, and fetch operations).
  • Cpu_per_session: Limits the total CPU used during a session.
  • Sessions_per_user: Maximum number of concurrent sessions that can be opened by the user.
  • Idle_time: Limits the amount of time a session is idle (i.e., nothing is running on its behalf).
  • Logical_reads_per_session: Total number of data blocks read (memory plus disk reads).
  • Logical_reads_per_call: Limits the logical reads per each session call (parse, execute, and fetch).
  • Private_sga: This is a limit applicable only to shared server architecture-based systems. It specifies a session's limits on the space it allocated in the shared pool component of the SGA.
  • Composite_limit: A composite limit is a sum of several of the previously described resource parameters, measured in service units. These resources are weighted by their importance. Oracle takes into account four parameters to compute a weighted composite_limit: cpu_per_session, connect_time, logical_reads_per_session, and private_sga. You can set a weight for each of these four parameters by using the alter resource cost statement, as shown in the following example:

    SQL> alter resource cost
      2  cpu_per_session 200
      3  connect_time 2;
    Resource cost altered.

When Do Profile Changes Go into Effect?

After you create a profile, when does it come into force? That is, when will the user be really restricted to four simultaneous sessions? The surprising answer is . . . never! Unless you have an initialization parameter modified from its default value, the profile changes you make will never come into force. The initialization parameter is the resource_limit parameter, and its default value is false. You need to set it to true, either by restarting the database after an init.ora file change or through the use of the alter system command, as shown here:

SQL> alter system set resource_limit=true;
System altered.

Make sure you have the resource_limit parameter set to true in order for the resource limits set by the profiles to be enforced. Otherwise, Oracle will ignore the limits set in the create or alter profile statement

Assign a profile

You assign a profile to a user by using the alter user statement, as follows

SQL> alter user gm_fomi
  2  profile test;
User altered.

Using the Database Resource Manager

The Database Resource Manager allows you to create resource plans, which specify how much of your resources should go to the various consumer groups. You can now group users based on their resource requirements, and you can have the Database Resource Manager allocate a preset amount of resources to these groups. Thus, you can easily prioritize among your users and jobs.
The resource plans that you formulate have the directives regarding resource usage, and you can easily modify these plans. Using the Database Resource Manager, it's possible for you to ensure that your critical user groups (called consumer groups here) are always guaranteed enough resources to perform their tasks. The resources that the Database Resource Manager can allocate are CPU usage, degree of parallelism, execution time limit, and the undo that can be generated by a consumer group. You can also limit the maximum number of concurrently active sessions allowed in each group.

Here's the sequence of actions you need to take to start using the Database Resource Manager:

Create a pending area

Before you can modify an old plan or create a new plan, you need to activate or create a pending area using the Database Resource Manager package in the following manner. All the resource plans you'll create will be stored in the data dictionary, and the following create pending area procedure will enable you to work with resource plans in a staging area before they are implemented:
SQL> execute dbms_resource_manager.create_pending_area;
PL/SQL procedure successfully completed.

You can also clear the pending area anytime you want by using the following procedure:
SQL> execute dbms_resource_manager.clear_pending_area;
PL/SQL procedure successfully completed.

Creating Consumer Groups

Once the pending area is active, you can create the consumer groups to which you'll allocate your users. You can assign users initially to one group, and you can later switch them to other groups if necessary. Now you'll create in your database three consumer groups : agency, direction, and national.

SQL> execute dbms_resource_manager.create_consumer_group (consumer_group => 'agency',comment => 'remote agencies'); 
PL/SQL procedure successfully completed. 

SQL> execute dbms_resource_manager.create_consumer_group (consumer_group => 'direction',-> comment => 'direction'); 
PL/SQL procedure successfully completed. 

SQL> execute dbms_resource_manager. create_consumer_group (consumer_group => 'national',-> comment => 'national office'); 
PL/SQL procedure successfully completed. SQL> 

Assigning Users to Consumer Groups

Users are already members of a default group, the default_consumer_group. Therefore, you need to first grant the three users privileges to switch their groups before you can actually switch them to your new groups. If you just grant the user PUBLIC the privilege to switch groups, you don't have to grant the privilege individually to all the users in the group. If you have a large number of users in each group, it is better to grant the user PUBLIC the privilege to switch groups, so you can avoid granting the privilege individually to each user.

SQL> execute dbms_resource_manager_privs.grant_switch_consumer_group('gm_fomi','low_group',TRUE);
PL/SQL procedure successfully completed. 

SQL> execute dbms_resource_manager.set_initial_consumer_group ('gm_fomi','low_group'); 
PL/SQL procedure successfully completed. 

Verifying Consumer Group Membership of Users

SQL> select username,initial_rsrc_consumer_group from dba_users;

------------------                  -------------------------------------------------------
SYS                                  SYS_GROUP
SYSTEM                         SYS_GROUP
DBSNMP                        DEFAULT_CONSUMER_GROUP
SIGNAT                          DEFAULT_CONSUMER_GROUP
OUTLN                           DEFAULT_CONSUMER_GROUP
WMSYS                           DEFAULT_CONSUMER_GROUP
GM_FOMI                      LOW_GROUP

Creating Resource Plans and Plan Directives

The heart of the Database Resource Manager is its capability to assign resource plans to various groups.  
Resource plans enable you to set limits on resource use by specifying limits on four variables: CPU, active session pool, degree of parallelism, and the order in which queued sessions will execute. Currently, for all four parameters, only the default levels and methods provided by Oracle can be used. 

Creating Resource Plans

Create your resource plan by invoking the DBMS_RESOURCE_MANAGER package :

SQL> execute dbms_resource_manager.create_pending_area;
PL/SQL procedure successfully completed.
SQL>  execute dbms_resource_Manager.create_plan (plan => 'membership_plan',comment => 'New Membership Recruitment');
PL/SQL procedure successfully completed. 

Creating a Plan Directive

You now have a resource plan, but the plan still doesn't have any resource limits assigned to it. You need to create a resource plan directive to assign specific resource limits to your resource plan.

SQL> execute dbms_resource_manager.create_plan_directive 
(plan => 'test_plan',GROUP_OR_SUBPLAN  => 'low_group', 
COMMENT => 'test_plan_directive',CPU_P1 => 70); 
PL/SQL procedure successfully completed.
SQL> execute dbms_resource_manager.create_plan_directive 
(plan => 'test_plan',GROUP_OR_SUBPLAN  => 'test_group', 
COMMENT => 'test_plan_directive',CPU_P1 => 30); 
PL/SQL procedure successfully completed. 
This plan directive assigns 70 percent of the available CPU at the first level to the low_group and the rest, 30 percent, to the test_group

In addition to the preceding groups, you'll need to add a plan directive for the default other_groups for the Database Resource Manager to accept your plan directives.

SQL> execute dbms_resource_manager.create_plan_directive (plan => 'test_plan',GROUP_OR_SUBPLAN  => 'OTHER_GROUPS', comment => '',cpu_p1 => 0);
PL/SQL procedure successfully completed.

If you don't include a resource directive for other_groups, Oracle won't let you use your directives for the other groups if the plan directive is for a primary or top plan.
You can now validate and submit your new top-level plan, membership_plan, in the following manner:

SQL>  execute dbms_resource_manager.validate_pending_area;
PL/SQL procedure successfully completed.
SQL> execute dbms_resource_manager.submit_pending_area;
PL/SQL procedure successfully completed.

Determining the Status of the Resource Plans

SQL> select plan,group_or_subplan,cpu_p1,cpu_p2,cpu_p3, status from dba_rsrc_plan_directives;

PLAN                      GROUP_OR_SUBPLA     CPU_P1     CPU_P2     CPU_P3 STATUS
------------------------- --------------- ---------- ---------- ---------- ----------
SYSTEM_PLAN               SYS_GROUP              100          0          0 PENDING
SYSTEM_PLAN               OTHER_GROUPS             0        100          0 PENDING
SYSTEM_PLAN               LOW_GROUP                0          0        100 PENDING
INTERNAL_QUIESCE          SYS_GROUP                0          0          0 PENDING
INTERNAL_QUIESCE          OTHER_GROUPS             0          0          0 PENDING
INTERNAL_PLAN             OTHER_GROUPS             0          0          0 PENDING
SYSTEM_PLAN               SYS_GROUP              100          0          0 ACTIVE
SYSTEM_PLAN               OTHER_GROUPS             0        100          0 ACTIVE
SYSTEM_PLAN               LOW_GROUP                0          0        100 ACTIVE
INTERNAL_QUIESCE          SYS_GROUP                0          0          0 ACTIVE
INTERNAL_QUIESCE          OTHER_GROUPS             0          0          0 ACTIVE
INTERNAL_PLAN             OTHER_GROUPS             0          0          0 ACTIVE

Enabling the Database Resource Manager

The fact that you created a new plan and plan directives and submitted your pending area doesn't mean that Oracle will automatically enforce the resource plans. It's our job to explicitly activate the Database Resource Manager, either by specifying the initialization parameter resource_manager_plan in the init.ora file or by using the alter system command in the following manner:

SQL> alter system set resource_manager_plan=MEMBERSHIP_PLAN ;
System altered. 
SQL> select * from v$rsrc_plan;

If you decide to deactivate the Database Resource Manager, you use the following command:
SQL> alter system set resource_manager_plan='';
System altered. 
SQL>  select * from v$rsrc_plan;
no rows selected

Saturday, May 26, 2012

oracle resource management scripts

Create resource manager plan

        (simple_plan => 'MY_PLAN'
        ,consumer_group1 => 'USERS', group1_cpu => 90
        ,consumer_group2 => 'ADMIN', group2_cpu => 10 );
     exception when others then


List the configuration of the Database Resource Manager 

set linesize 1000 
col plan form a40 heading "Plan Name"
col group_or_subplan form a15 heading "Sub-Plan"
col status form a6 heading "Status"
col cpu_p1 form 999 heading "CPU1"
col cpu_p2 form 999 heading "CPU2"
col cpu_p3 form 999 heading "CPU3"
col cpu_p4 form 999 heading "CPU4"

PROMPT Plans on database

select plan, cpu_method, status from dba_rsrc_plans; 

PROMPT Resource Plan Directives

select plan, group_or_subplan, type, cpu_p1, cpu_p2, cpu_p3, cpu_p4, status 
  from dba_rsrc_plan_directives 
order by 8,1,2,3,4,5,6; 

PROMPT Consumer Group Privileges

select * from dba_rsrc_consumer_group_privs; 

PROMPT Default User Consumer Groups

select username, initial_rsrc_consumer_group from dba_users; 

assign a resource manager plan to users


&1 - The resource consumer group
&2 - The user to be assigned the consumer group

set verify off

define consumer_group = UPPER('&1')
define user = UPPER('&2')

      ( grantee_name => &user
      , consumer_group => &consumer_group
      , grant_option => FALSE);

     (user => &user
     ,consumer_group  => &consumer_group ); 



Monitor Database Resource Manager Sessions

col sid form 999 heading "SID"
col serial# form 99999 heading "Serial"
col program form a28 heading "Program"
col username form a12 heading "Username"
col resource_consumer_group form a22 heading "Consumer Group"
col name form a12 heading "Name"
col active_sessions form 99999 head "Active"
col consumed_cpu_time form 99999999 heading "Con CPU"
col sessions_queued form 99999 heading "Queued" 

spool monrsrc.lst

select sid,serial#,username,program,resource_consumer_group 
from v$session

select name,active_sessions,consumed_cpu_time
       ,requests,cpu_wait_time,cpu_waits, sessions_queued
from v$rsrc_consumer_group

spool off

Drop a resource manager plan and any associated subplans


&1 - The Plan Name to drop

set serveroutput on

col plan form a12 heading "Plan Name"

select plan, cpu_method, status from dba_rsrc_plans; 

ACCEPT plan_name PROMPT 'Enter value for Plan to Drop : '

spool drop_rsrc.lst


l_plan_name DBA_RSRC_PLANS.plan%TYPE := UPPER('&plan_name') ;


   dbms_output.put ('Creating Pending Area...');
   dbms_output.put_line ('Pending Area Created.');

   dbms_output.put ('Deleting Plan '||l_plan_name||'...');
   dbms_resource_manager.delete_plan( plan => l_plan_name); 
   dbms_output.put_line ('Plan Deleted.');

   FOR con_grp IN ( SELECT group_or_subplan 
                    FROM  dba_rsrc_plan_directives 
                    WHERE plan = l_plan_name 
                     ) LOOP

      dbms_output.put ('Deleting Consumer Group '
            consumer_group => con_grp.group_or_subplan ); 
      dbms_output.put_line ('Consumer Group Deleted.');


   dbms_output.put ('Submitting Pending Area ...');
    dbms_output.put_line ('Pending Area Submitted.');

   dbms_output.new_line ;
   dbms_output.put_line ('Error Occurred  :'||SQLERRM);

   dbms_output.put_line ('... Pending Area Cleared.');


spool off

Lists usage information of consumer groups

SELECT name,consumed_cpu_time
FROM   v$rsrc_consumer_group
ORDER BY name;

Lists all resource plans


COLUMN comments FORMAT A50

SELECT plan,
FROM   dba_rsrc_plans
ORDER BY plan;

Lists all consumer groups


COLUMN comments FORMAT A50

SELECT consumer_group,
FROM   dba_rsrc_consumer_groups
ORDER BY consumer_group;



Disable redo log generation generation before bulk load of data

Redo logs are there for recovering your database in the event of a crash or an OS file corruption. If you don't have redo logging on, then if anything goes wrong with the database your users will lose all their work since the last good back up.Not logging in a transactional system is a very bad idea.

But in some circumstances you can disable redo log generation without worries and improves performance
  • In test environment
  • bulk load of data
  • creating/recreating of indexes
The NOLOGGING mode improves performance because it generates much less log data in the redo log files helping in eliminating the time needed to execute the redo generation (latch acquisition, redolog writing, etc.). The user is responsible for backing up the data after a NOLOGGING insert operation in order to be able to perform media recovery.

How to avoid the checkpoint not complete error in Oracle 9i

if you frequently load large amounts of data in an Oracle database, then it is very likely that you get the message checkpoint not complete in the alert log file oracle.

The "checkpoint not complete" messages are generated because the logs are switching so fast that the checkpoint associated with the log switch isn’t complete.

Oracle suggests that you might consider setting archive_lag_target to zero to reduce "checkpoint not complete" messages:

alter system set archive_lag_target=0 scope=both;

Overall Oracle performance can be dramatically improved by increasing the log sizes so that logs switch at the recommended interval of 15 to 30 minutes.   
Identify the current size of the redo log members from v$log, record the number of log switches per hour and increase the size of the log to allow Oracle to switch at the recommended rate of one switch per 15 to 30 minutes.   
For example, if the database redo log size is 1 megabyte and you are switching logs every 1 minute, you will need to increase the log size to 30 megabytes in size to allow it to switch every 30 minutes.   

You need to ensure that the on-line redo logs don’t switch too often during periods of high activity and switch often enough during times of low processing workloads.   

This should reduce the delays from the checkpoint not complete errors.

Oracle Shared pool layers

The shared pool caches various types of program data. For example, the shared pool stores parsed SQL, PL/SQL code, system parameters, and data dictionary information. The shared pool is involved in almost every operation that occurs in the database. For example, if a user executes a SQL statement, then Oracle Database accesses the shared pool.

Library Cache

The library cache is a shared pool memory structure that stores executable SQL and PL/SQL code. This cache contains the shared SQL and PL/SQL areas and control structures such as locks and library cache handles. In a shared server architecture, the library cache also contains private SQL areas.
When a SQL statement is executed, the database attempts to reuse previously executed code. If a parsed representation of a SQL statement exists in the library cache and can be shared, then the database reuses the code, known as a soft parse or a library cache hit. Otherwise, the database must build a new executable version of the application code, known as a hard parse or a library cache miss.















Data Dictionary Cache

The data dictionary is a collection of database tables and views containing reference information about the database, its structures, and its users. Oracle Database accesses the data dictionary frequently during SQL statement parsing.
The data dictionary is accessed so often by Oracle Database that the following special memory locations are designated to hold dictionary data:
  • Data dictionary cache
    This cache holds information about database objects. The cache is also known as the row cache because it holds data as rows instead of buffers.
  • Library cache
All server processes share these caches for access to data dictionary information.

Server Result Cache

Unlike the buffer pools, the server result cache holds result sets and not data blocks. The server result cache contains the SQL query result cache and PL/SQL function result cache, which share the same infrastructure.
A client result cache differs from the server result cache. A client cache is configured at the application level and is located in client memory, not in database memory.

Reserved Pool

The reserved pool is a memory area in the shared pool that Oracle Database can use to allocate large contiguous chunks of memory.
Allocation of memory from the shared pool is performed in chunks. Chunking allows large objects (over 5 KB) to be loaded into the cache without requiring a single contiguous area. In this way, the database reduces the possibility of running out of contiguous memory because of fragmentation.
Infrequently, Java, PL/SQL, or SQL cursors may make allocations out of the shared pool that are larger than 5 KB. To allow these allocations to occur most efficiently, the database segregates a small amount of the shared pool for the reserved pool.

Minimise redo log generation during import in Oracle 9i

  • Use direct path
  • Import without the indexes (use indexes=NO)
  • Create the index script file (with indexfile=indexscript.sql)
  • Modify the index script file to add NOLOGGING to the CREATE INDEX statements
  • Run the index script file
 That way you avoid Logging on the indexes at least.

Saturday, May 19, 2012

Script to resize Oracle Datafiles

Over-allocation of space at the file level affects the backup/recovery window, file checking times and, most  painfully, limits the potential allocation of space to a tablespace that needs the extra room. A simpler solution would be to review the evolution of the script, which lets you know which files can and cannot be resized to create more space.

It's possible to release space from data files but only down to the first block of data. This is done with the 'alter database' command.

The following script allows to calculate the amount of space used by each tablespace

SELECT   tablespace_name, SUM (bytes) bytes_full
    FROM   dba_extents
GROUP BY   tablespace_name;

The following scripts allows to calculate the total space available for each tablespace

SELECT   tablespace_name, SUM (bytes) bytes_total
    FROM   dba_data_files
GROUP BY   tablespace_name;

The following script allows to find the last data block that has been inserted for each file

SELECT   tablespace_name, file_id, MAX (block_id) max_data_block_id
    FROM   dba_extents
GROUP BY   tablespace_name, file_id;

The following allows to find the free space in each file above the last data block inserted

SELECT   a.tablespace_name, a.file_id, b.bytes bytes_free
  FROM   (  SELECT   tablespace_name, file_id, MAX (block_id) max_data_block_id
              FROM   dba_extents
          GROUP BY   tablespace_name, file_id) a, dba_free_space b
 WHERE       a.tablespace_name = b.tablespace_name
         AND a.file_id = b.file_id
         AND b.block_id > a.max_data_block_id;

Finally the following will allow to generate alter statements to resize your datafiles

SELECT      'alter database '
         || ' datafile '''
         || b.file_name
         || ''''
         || ' resize '
         || GREATEST (TRUNC (bytes_full / .7), (bytes_total - bytes_free))
  FROM   v$database a,
         dba_data_files b,
         (  SELECT   tablespace_name, SUM (bytes) bytes_full
              FROM   dba_extents
          GROUP BY   tablespace_name) c,
         (  SELECT   tablespace_name, SUM (bytes) bytes_total
              FROM   dba_data_files
          GROUP BY   tablespace_name) d,
         (SELECT   a.tablespace_name, a.file_id, b.bytes bytes_free
            FROM   (  SELECT   tablespace_name,
                               MAX (block_id) max_data_block_id
                        FROM   dba_extents
                    GROUP BY   tablespace_name, file_id) a,
                   dba_free_space b
           WHERE       a.tablespace_name = b.tablespace_name
                   AND a.file_id = b.file_id
                   AND b.block_id > a.max_data_block_id) e
 WHERE       b.tablespace_name = c.tablespace_name
         AND b.tablespace_name = d.tablespace_name
         AND bytes_full / bytes_total < .7
         AND b.tablespace_name = e.tablespace_name
         AND b.file_id = e.file_id;

Setting up Autotrace in SQL*Plus

AUTOTRACE is a facility within SQL*Plus to show us the explain plan of the queries we've executed, and
the resources they used. There is more than one way to get AUTOTRACE configured.

This is how i do to get AUTOTRACE working:
•  cd $ORACLE_HOME/rdbms/admin (or cd %ORACLE_HOME%/rdbms/admin on Windows)
•  log into SQL*Plus as SYSTEM ==> sqlplus system/pass@alias
•  run @utlxplan
You can replace the GRANT TO PUBLIC with some user if you want. By making it public, you let
anyone trace using SQL*Plus. This prevents every user from having to install their own plan table. The alternative is for you to run @utlxplan in every schema from which you
want to use AUTOTRACE.
The next step is creating and granting the PLUSTRACE role:
•  cd $ORACLE_HOME/sqlplus/admin (or cd %ORACLE_HOME%/sqlplus/admin on Windows)
•  log into SQL*Plus as SYS or AS SYSDBA
•  run @plustrce
Again, you can replace PUBLIC in the GRANT command with some user if you want.

Wednesday, May 16, 2012

This is how i customize my sqlplus prompt

I often use sqlplus to perform my daily administrative tasks and i work on multiple servers that contain multiple databases, each database contains multiple accounts.
When connected to a database, i need to know my username and my database connection to reassure me that I point to the correct database in order to avoid errors that could be catastrophic.

To customize your sqlplus prompt
  • Navigate to the directory $ORACLE_HOME/sqlplus/admin
  • Create a file login.sql (or edit the file if it already exists) using vi on unix / Linux or notepad on windows
     The next time you will login your sqlplus prompt will look like this : user@alias

Here is a complete list of SQL*Plus variables that you can use to customize your prompt.

There are eight variables defined during SQL*Plus installation. These variables only differ from user defined variables by having predefined values.
Table 12-3 Variables Predefined at SQL*Plus Installation
Variable Name Contains
_CONNECT_IDENTIFIER Connection identifier used to make connection, where available.
_DATE Current date, or a user defined fixed string.
_EDITOR Specifies the editor used by the EDIT command.
_O_VERSION Current version of the installed Oracle Database.
_O_RELEASE Full release number of the installed Oracle Database.
_PRIVILEGE Privilege level of the current connection.
_SQLPLUS_RELEASE Full release number of installed SQL*Plus component.
_USER User name used to make connection.

Tuesday, May 15, 2012

Establish a direct connection to Oracle from sqlplus (without an alias)

People like us who change environments all the time with various customers, not to waste time configuring a connection alias in the tnsnames.ora file you can directly connect to an ORACLE database from sqlplus using

sqlplus user/pass@server_ip:port/sid

ex: sqlplus guy/fomi@

How to fix ORA-00214

One of our test servers has terminated abnormally in the night.

After restarting the server, oracle sends us this error message during the startup of one of our bases :

ORA-00214: controlfile '/u02/oradata/control01.ctl' version 498359
inconsistent with file '/u02/oradata/control03.ctl' version 498341

The solution consists in opening the database with a single good copy
of the control file and then shutting the database down and copying
that version of the control file onto the other mirrored copies.
That will cause the next startup to succeed. The steps to be followed

1. If the database is still up, do a shutdown abort now.

2. Edit the init.ora file for this instance (or config.ora in an ifile

Find the CONTROL_FILES parameter and modify it to include
just ONE copy of the control file that you have reasons to
believe is up-to-date. For example, if you only have two
mirrored copies X and Y of the control file:


and you know you have accidentally overwritten X with an old
copy, make


If you are not sure about it, choose any one of the control file
copies and remove or comment out all the other copies from the
CONTROL_FILES parameter.

3. Start up the database in restricted mode.


If the database comes up fine, move on to Step 4.

If instead you get ORA-1122, ORA-1110, and ORA-1207, go back to
Step 2 and make the CONTROL_FILES parameter point to another one
of the mirrored copies. If you have already tried each and
every one of the mirrored copies unsuccessfully, you must create
a new control file for the database. See the Solution Reference
to PR entry 1012929.6 ("How to Recreate the Control File").

If you get ORA-1113 and ORA-1110 pointing to one of the datafiles,
it means the copy of the control file you picked is good, but
the referenced datafile must be recovered before the database can be
opened. Try issuing a RECOVER DATABASE command and applying the
logs you are prompted for. You may have to resort to the online
logs to complete media recovery. For further details, see the
Solution Reference to PR entry 1012943.6 on ORA-1113. Once the
datafile is recovered, issue an ALTER DATABASE OPEN.

4. Shut the database down (normal or immediate).

5. Make all copies of the control file consistent.

Copy the good mirrored copy of the control file that you just used
to bring the database up onto all other copies, as originally listed
in the CONTROL_FILES parameter of your init.ora file (or config.ora
in an ifile configuration).

6. Restore the CONTROL_FILES parameter to its original value.

Edit the init.ora file for this instance (or config.ora in an ifile
configuration) to make the CONTROL_FILES parameter include
all mirrored copies of the control file again.

7. Start up the database.

Source : Metalink note 1014751.6

Monday, May 14, 2012

SQLPLUS SET System Variable Summary

I need to lookup these variables very often for my sqlplus scripts

System Variable Description
Sets automatic registering of scripts through the DBMS_APPLICATION_INFO package.
Sets the number of rows, called a batch, that SQL*Plus will fetch from the database at one time.
Controls when Oracle Database commits pending changes to the database.
Sets the automatic printing of bind variables.
ON sets the RECOVER command to automatically apply the default filenames of archived redo log files needed during recovery.
Displays a report on the execution of successful SQL DML statements (SELECT, INSERT, UPDATE or DELETE).
Sets the non-alphanumeric character used to end PL/SQL blocks to c.
Sets the non-alphanumeric character used to separate multiple SQL*Plus commands entered on one line to c.
In iSQL*Plus, SET COLSEP determines the column separator character to be printed between column output that is rendered inside <PRE> tags. Sets the text to be printed between selected columns.
Sets the character you can use to terminate a substitution variable reference if you wish to immediately follow the variable with a character that SQL*Plus would otherwise interpret as a part of the substitution variable name.
Controls the number of batches after which the COPY command commits changes to the database.
Sets the suppression of the comparison of datatypes while inserting or appending to tables with the COPY command.
Sets the character used to prefix variables to c.
Sets the depth of the level to which you can recursively describe an object.
Controls whether the START command lists each command in a script as the command is executed.
Sets the default filename for the EDIT command.
Controls where on a page each report begins.
Defines the character you enter as the escape character.
Displays the number of records returned by a query when a query selects at least n records.
Checks to make sure that SQL statements conform to the ANSI/ISO SQL92 standard.
Controls when output is sent to the user's display device.
Controls printing of column headings in reports.
Defines the character you enter as the heading separator character.
Changes the default instance for your session to the specified instance path.
Sets the total number of characters that SQL*Plus displays on one line before beginning a new line.
Sets the starting position from which CLOB and NCLOB data is retrieved and displayed.
Specifies the location from which archive logs are retrieved during recovery.
Sets maximum width (in bytes) for displaying LONG, CLOB, NCLOB and XMLType values; and for copying LONG values.
Sets the size (in bytes) of the increments in which SQL*Plus retrieves a LONG, CLOB, NCLOB or XMLType value.
Outputs HTML marked up text, which is the output used by iSQL*Plus.
Sets the number of blank lines to be printed from the top of each page to the top title.
Sets the text that represents a null value in the result of a SQL SELECT command.
Sets the default format for displaying numbers.
Sets the default width for displaying numbers.
Sets the number of lines in each page.
Enables you to control scrolling of your terminal when running reports.
RECSEP tells SQL*Plus where to make the record separation.
Display or print record separators.
Controls whether to display the output (that is, DBMS_OUTPUT PUT_LINE) of stored procedures or PL/SQL blocks in SQL*Plus.
Enables correct alignment for terminals that display shift characters.
Controls whether SQL*Plus lists the old and new settings of a SQL*Plus system variable when you change the setting with SET.
Controls whether SQL*Plus puts blank lines within a SQL command or script.
Converts the case of SQL commands and PL/SQL blocks just prior to execution.
Sets the character sequence SQL*Plus displays as a prompt after you continue a SQL*Plus command on an additional line using a hyphen (–).
Sets the prompt for the second and subsequent lines of a SQL command or PL/SQL block.
Sets the behavior or output format of VARIABLE to that of the release or version specified by x.y[.z].
Sets the SQL*Plus prefix character.
Sets the SQL*Plus command prompt.
Sets the character used to end and execute SQL commands to c.
Sets the default file that SQL*Plus uses in commands that refer to scripts.
Determines how SQL*Plus formats white space in terminal output.
Controls the display of output generated by commands executed from a script.
Controls the display of the current time.
Controls the display of timing statistics.
Determines whether SQL*Plus puts trailing blanks at the end of each displayed line.
Determines whether SQL*Plus puts trailing blanks at the end of each spooled line.
Sets the character used to underline column headings in SQL*Plus reports to c.
Controls whether SQL*Plus lists the text of a SQL statement or PL/SQL command before and after SQL*Plus replaces substitution variables with values.
Controls whether SQL*Plus truncates the display of a SELECTed row if it is too long for the current line width.
Defines the base URI to use. This is useful to change the prefix of the file to access when writing generic XQuery expressions.
Controls the ordering of results from an XQuery.
Sets the preservation mode for notes created or returned.
Specifies an XQuery context item which can be either a node or a value.