Move a datafile with RMAN

Using RMAN is the best way before 12c to relocate a datafile with a minimum downtime. The only downtime is for switching from the old datafile to the new one and recover it. That means that the datafile size as no impact on the downtime.

Check schmea report before moving datafile.

Here is the situation before moving the datafile

RMAN> report schema
2> ;

using target database control file instead of recovery catalog
Report of database schema for database with db_unique_name XE

List of Permanent Datafiles
===========================
File Size(MB) Tablespace RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1 360 SYSTEM *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSTEM.DBF
2 650 SYSAUX *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\UNDOTBS1.DBF
3 25 UNDOTBS1 *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSAUX.DBF
4 100 USERS *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS.DBF


List of Temporary Files
=======================
File Size(MB) Tablespace Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1 20 TEMP 32767 C:\ORACLEXE\APP\ORACLE\ORADATA\XE\TEMP.DBF


1.Create a copy of datafile to new destination.

The first step is to create a copy of your datafile in the new destination. Here, we will copy the USERS datafile to
C:\ORACLEXE\APP\ORACLE\ORADATA2\XE:


RMAN> copy datafile 4 to 'C:\ORACLEXE\APP\ORACLE\ORADATA2\XE\USERS.DBF';

Starting backup at 14-01-27
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=50 device type=DISK
channel ORA_DISK_1: starting datafile copy
input datafile file number=00004 name=C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS.DBF
output file name=C:\ORACLEXE\APP\ORACLE\ORADATA2\XE\USERS.DBF tag=TAG20140127T132133 RECID=1 STAMP=837955296
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:07
Finished backup at 14-01-27

2.Take tablespace offline.

Now I hae a copy of my datafile in the new destination, I have to switch from the old datafile to the new one. Of course this operation cannot be done online, I’ll have to put my tablespace offline, this is the begining of the downtime.

RMAN> SQL 'ALTER TABLESPACE USERS OFFLINE';

sql statement: ALTER TABLESPACE USERS OFFLINE

3.Switch old datafile to new datafile.

Now I can switch from the old datafile to the new one:

RMAN> SWITCH DATAFILE 4 TO COPY;

datafile 4 switched to datafile copy "C:\ORACLEXE\APP\ORACLE\ORADATA2\XE\USERS.DBF"

4.Recover the datafile.

Now we have to recover the datafile:

RMAN> RECOVER DATAFILE 4;

Starting recover at 14-01-27
using channel ORA_DISK_1

starting media recovery
media recovery complete, elapsed time: 00:00:01

Finished recover at 14-01-27

5.Put tablespace back to online.

And we put back the tablespace USERS online:

RMAN> SQL 'ALTER TABLESPACE USERS ONLINE';

sql statement: ALTER TABLESPACE USERS ONLINE

6. Check status now.

Here is the new situation:

Report of database schema for database with db_unique_name XE

RMAN> report schema

List of Permanent Datafiles
===========================
File Size(MB) Tablespace RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1 360 SYSTEM *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSTEM.DBF
2 650 SYSAUX *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\UNDOTBS1.DBF
3 25 UNDOTBS1 *** C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSAUX.DBF
4 100 USERS *** C:\ORACLEXE\APP\ORACLE\ORADATA2\XE\USERS.DBF

List of Temporary Files
=======================
File Size(MB) Tablespace Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1 20 TEMP 32767 C:\ORACLEXE\APP\ORACLE\ORADATA\XE\TEMP.DBF

The old datafile is kept as copy:

7.Check old datafile copy.

RMAN> list copy of datafile 4;

List of Datafile Copies
=======================

Key File S Completion Time Ckp SCN Ckp Time
------- ---- - --------------- ---------- ---------------
2 4 A 14-01-27 379024 14-01-27
Name: C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS.DBF

Check 8.Remove old copy if do not need

We can remove it as we no longer need it:

RMAN> DELETE DATAFILECOPY 2;

released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=50 device type=DISK
List of Datafile Copies
=======================

Key File S Completion Time Ckp SCN Ckp Time
------- ---- - --------------- ---------- ---------------
2 4 A 14-01-27 379024 14-01-27
Name: C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS.DBF

Do you really want to delete the above objects (enter YES or NO)? yes
deleted datafile copy
datafile copy file name=C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS.DBF RECID=2 STAMP=837955601

Deleted 1 objects


And its done :)




I hope this article helped you. Your suggestions/feedback are most welcome.

Keep learning... Have a great day!!!

ora-01244: unnamed datafile(s) added to control file by media recovery

Cause: Media recovery with a backup control file or a control file that was rebuilt, encountered the creation of a datafile that was not in the control file. An entry has been added to the control file for the new datafiles, but with the file name UNNAMEDnnnn, where nnnn is the file number. Attached errors describe the file names that were originally used to create the files.

Action: Rename the files to valid file names and resume recovery. If necessary the command ALTER DATABASE CREATE DATAFILE may be used to create a file suitable for recovery and do the rename. If the file is not going to be recovered then take it offline with the FOR DROP option.

You'll encouter below error in alert log:

Errors in file /u01/app/11.2.0.3/diag/rdbms/odsprod/odsprod/trace/odsprod_pr00_16095.trc:

ORA-00283: recovery session canceled due to errors
ORA-01244: unnamed datafile(s) added to control file by media recovery
ORA-01110: data file 684: '/OSP/Data45/osp/data/tblspc_osp_686.dbf'
Slave exiting with ORA-283 exception

And your database recovery will abort

Now there can be a couple of scenarios, where in you may encounter this error, and their respective solutions .

1.You restored a full database and are recovering it through archives from source

Here, you are recovering after a full restore and hence the error says that the required data file doesn't exist.

To over come this issue, you simply have to execute below SQL:

alter database create datafile file#_from_error as '/new/path/to/data/file.dbf';

So, in our case that would be:

SQL> alter database create datafile 684 as '/bkp_loc/OSP/data/tblspc_osp_686.dbf';

The path is where you want the data file to be created. This can be similar to the one reported in error (if you have same path as source) or could be different, as in this case.

Also, if you are using ASM or to create Oracle managed datafile name

SQL> alter database create datafile 684 as new;

Now, you can continue with your recovery.

2.You lost a control file and restored it from a backup after which you had added data files to the database

Here, the data files already exist, (but they didn't at the time you backed up control file) but just that the restored control file is from time before the data files were added and hence not aware of them.

So, in this case, we can just rename the file to its existing file:

SQL> alter database rename file '/u01/app/product/11.2.0/dbhome_1/dbs/UNNAMED00684' to '/OSP/Data45/osp/data/tblspc_osp_686.dbf';

While renaming or recreating, just ensure that the target file being created doesn't already exist or if renaming, you aren't renaming it to other existing data files.

In any case if you know that you dont need that file, you can mark the same offline

I hope this article helped you. Your suggestions/feedback are most welcome.

Keep learning... Have a great day!!!

SQL Tuning Advisor for SQL_ID

Here we are going to discuss how to do SQL Tuning Advisor for SQL_ID.

1.Create SQL Tuning Advisor task

DECLARE

  my_task_name VARCHAR2(30);

begin

my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(sql_id => '7a6b4442j5pcz',scope => 'COMPREHENSIVE',time_limit => 60,task_name => 'STA:7a6b4442j5pcz',description => '7a6b4442j5pcz');

end;

/

2.Check if the task has been created

SELECT task_name FROM DBA_ADVISOR_LOG WHERE owner = ‘TEST’;

3. Run Task 

EXEC DBMS_SQLTUNE.execute_tuning_task( task_name => 'STA:7a6b4442j5pcz');

3.Checking the Status

SELECT status FROM DBA_ADVISOR_TASKS WHERE task_name = ‘STA:7a6b4442j5pcz’;
SELECT sofar, totalwork, username FROM V$ADVISOR_PROGRESS ;

3. View results 

SET LONG 10000

SET PAGESIZE 1000

SET LINESIZE 200

SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('STA:7a6b4442j5pcz') from dual;

DBMS_SQLTUNE.REPORT_TUNING_TASK('STA:7A6B4442J5PCZ')

--------------------------------------------------------------------------------

GENERAL INFORMATION SECTION

----------------------------------------------------------------------------

---

Tuning Task Name                  : STA:7a6b4442j5pcz

Tuning Task Owner                 : SYS

Scope                             : COMPREHENSIVE

Time Limit(seconds)               : 60

Completion Status                 : COMPLETED

Started at                        : 10/16/2012 19:47:

27

Completed at                      : 10/16/2012 19:47:54

Number of SQL Profile Findings    : 1

----------------------------------------------------------

FINDINGS SECTION (1 finding)

--------------------------------------------------------------------

-----------

1- SQL Profile Finding (see explain plans section below)

--------------------------------------------------------

  A potentially better execution plan was found for thi

s statement.

  Recommendation (estimated benefit: 99.94%)

  ------------------------------------------

  - Consider accepting the recommended SQL profile.

    execute dbms_sqltune.accept_sql_profile(task_nam

e => 'STA:7a6b4442j5pcz',

            replace => TRUE);

4.Delete task.

BEGIN

DBMS_SQLTUNE.drop_tuning_task (task_name => 'STA:7A6B4442J5PCZ');

END;

/

hope this article helped you. Your suggestions/feedbacks are most welcome.

Keep learning... Have a great day!!!

To Find out If MySQL Is Running On Linux Or Not

Recently got a chance to work on Mysql database.So would like to share few besic article reagrding mysql Database.Below article will help you to check whether your mysql server is runnign or not.

You can use mysql startup script or mysqladmin command to find out if it is running on Linux. Then you can use ps command and telnet command too (it is not reliable but it works.). mysqladmin is a utility for performing administrative operations. You can also use shell script to monitor MySQL server. You can use mysqladmin as follows:

# mysqladmin -u root -p status

Output:

Enter password:
Uptime: 4  Threads: 1  Questions: 62  Slow queries: 0  Opens: 51  Flush tables: 1  Open tables: 45  Queries per second avg: 15.500

If MySQL serer is running it will display output as above. It displays uptime and number of queries etc. If server is not running then it will dump error as follows
# mysqladmin -u root -p status
Output:

mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'
Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!

Under Debian Linux you can type following command to find out if MySQL server is running or not

# /etc/init.d/mysql status

Output:

/usr/bin/mysqladmin  Ver 8.41 Distrib 4.1.15, for pc-linux-gnu on i486
Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL license
Server version          4.1.15-Debian_1-log
Protocol version        10
Connection              Localhost via UNIX socket
UNIX socket             /var/run/mysqld/mysqld.sock
Uptime:                 4 min 16 sec
Threads: 1  Questions: 66  Slow queries: 0  Opens: 51  Flush tables: 1  Open tables: 45  Queries per second avg: 0.258

If you are using RedHat of Fedora then you can use following script"
# service mysqld status

OR

# /etc/init.d/mysqld status

 hope this article helped you. Your suggestions/feedbacks are most welcome.

Keep learning... Have a great day!!!

EXP-00002: error in writing to export file

While exporting table or schema using exp/imp utility you may come across below error.

Most of the time this error occurs due to insufficient space available on disk.so confirm space is available where you are taking taking export dump and re-run export.

[oracle@DEV admin]$ exp test/test@DEV tables=t1,t2,t3,t4 file=exp_tables.dmp log=exp_tables.log

Export: Release 9.2.0.8.0 - Production on Thu Sep 10 12:25:52 2015

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to: Oracle9i Enterprise Edition Release 9.2.0.8.0 - Production

With the Partitioning, OLAP and Oracle Data Mining options

JServer Release 9.2.0.8.0 - Production

Export done in US7ASCII character set and AL16UTF16 NCHAR character set

About to export specified tables via Conventional Path ...

. . exporting table t1 1270880 rows exported

. . exporting table t2 2248883 rows exported

. . exporting table t3 2864492 rows exported

. . exporting table t4

EXP-00002: error in writing to export file

EXP-00002: error in writing to export file

EXP-00000: Export terminated unsuccessfully

I hope this article helped you. Your suggestions/feedbacks are most welcome.
Keep learning... Have a great day!!!