Database Partial Restore
PRE-IMPLEMENTATION STEPS
1) Make sure you have a backup of the System, Sysaux, Undo and the data Tablespace
2) Make sure you have all the archive logs from the time the backup was taken to the time
you want to restore to.
3) Make sure you have enough space to restore the above tablespaces
Relational Database Consulting
Page 1
IMPLEMENTATION STEPS
Step 1. Connect to the database and check the table SIZE, TABLESPACE and OWNER as
follows:
SQL> select OWNER, SEGMENT_NAME, SEGMENT_TYPE, TABLESPACE_NAME , bytes/1024 from dba_segments where owner
=’TABLE_OWNER’ and SEGMENT_NAME=’TABLE_NAME’ ;
In our case we are going to export a table name 'JAMES_DEBUG' and the owner of the table
is 'XSL'
SQL> select OWNER, SEGMENT_NAME, SEGMENT_TYPE , TABLESPACE_NAME, bytes/1024 from dba_segments where owner
='XSL' and SEGMENT_NAME='JAMES_DEBUG' ;
OWNER
-------------XSL
SEGMENT_NAME
------------------------JAMES_DEBUG
SEGMENT_TYPE
----------------------------TABLE
TABLESPACE_NAME
---------------XSL_DATA
BYTES/1024
-------------1,572,864
Step 2. Check which datafiles the table resides on, by querying the dba_extents view.
select distinct FILE_ID from dba_extents where SEGMENT_NAME='JAMES_DEBUG' and
owner= 'XSL' ;
FILE_ID
---------17
16
18
As a bonus let’s check how many datafiles make up this tablespace:
select FILE_NAME , FILE_ID, TABLESPACE_NAME , BYTES/1024/1024 from dba_data_files
where TABLESPACE_NAME='XSL_DATA'
FILE_NAME
FILE_ID TABLESPACE_NAME
------------------------------------------------------------- ------------------ ---------------------------+DATA/cfmsp2/datafile/xsl_data.259.777231375
16
XSL_DATA
+DATA/cfmsp2/datafile/xsl_data.260.777231375
17
XSL_DATA
+DATA/cfmsp2/datafile/xsl_data.261.777231721
18
XSL_DATA
+DATA/cfmsp2/datafile/xsl_data.262.777231795
24
XSL_DATA
Relational Database Consulting
BYTES/1024/1024
----------------15000
15000
15000
15000
Page 2
So rather than restore the whole tablespace we are going to restore 3 of the 4 datafiles that
make the tablespace. So datafile, FILe_ID 24 will not be restored.
Step 3. Partial Database Restore
To do a partial database restore you need to restore the mandatory files for a database to
run which are:
1. Spfile
2. Controlfile
3. System tablespace
4. Sysaux tablespace (also required by the exp/imp or expdp/impdp)
5. Undo tablespace
Then lastly the datafile/s that contain the table/s that we want to export! In our case I will
only restore datafiles 16, 17 and 18 only.
i.)
Restore the spfile:
connect target
connect rcvcat rman11203/rman11203@recovery_catalogDB;
set dbid 896914363 ;
run {
startup force nomount ;
set until time "to_date('04-DEC-2013 07:00:00','DD-MON-YYYY HH24:MI:SS')";
allocate channel t1 type 'SBT_TAPE' PARMS='ENV=(NB_ORA_CLIENT=XXXXXXX)';
restore spfile to pfile ’/app/oracle/local/initsid.ora ;
release channel t1;
}
I got this ERROR Message repeatedly!
RMAN> startup nomount
startup failed: ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file '/app/oracle/product/11.2.0.3/db_1/dbs/initcfmsp2.ora'
starting Oracle instance without parameter file for retrieval of spfile
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of startup command at 12/04/2013 15:44:42
RMAN-04014: startup failed: ORA-04031: unable to allocate 3981064 bytes of shared memory
("shared pool","unknown object","sga heap(1,0)","FileOpenBlock")
RMAN> exit
This error message is caused by, I quote: “It means that we should increase
database shared memory. To do this, we need to exit from RMAN and define
environment variable ORA_RMAN_SGA_TARGET:”
Thus to resolve this problem we simply export this variable:
Relational Database Consulting
Page 3
$ export ORA_RMAN_SGA_TARGET=450
Thanks to this link below that came up with the solution!
http://www.iliachemodanov.ru/en/blog-en/21-databases/50-oracle-backup-andrestore-en
Output from the spfile restore command:
startup failed: ORA-01078: failure in processing system parameters
LRM-00109: could not open parameter file '/app/oracle/product/11.2.0.3/db_1/dbs/initcfmsp2.ora'
starting Oracle instance without parameter file for retrieval of spfile
Oracle instance started
Total System Global Area
Fixed Size
Variable Size
Database Buffers
Redo Buffers
367439872 bytes
2221600 bytes
197134816 bytes
163577856 bytes
4505600 bytes
connected to recovery catalog database
executing command: SET DBID
database name is "CFMSP2" and DBID is 896914363
executing command: SET until clause
allocated channel: t1
channel t1: SID=266 device type=SBT_TAPE
channel t1: Veritas NetBackup for Oracle - Release 7.0 (2010070805)
Starting restore at 04-DEC-13
channel t1: starting datafile backup set restore
channel t1: restoring SPFILE
output file name=/app/oracle/product/11.2.0.3/db_1/dbs/spfilecfmsp2.ora
channel t1: reading from backup piece bk_240819_1_833249285
channel t1: piece handle=bk_240819_1_833249285 tag=HOT_DB_BK_LEVEL0
channel t1: restored backup piece 1
channel t1: restore complete, elapsed time: 00:01:15
Finished restore at 04-DEC-13
released channel: t1
Recovery Manager complete.
Relational Database Consulting
Page 4
ii.)
Restore the controlfile
Startup the database nomount using the just restored spfile.
SQL> startup force nomount;
Restore the controlfile as follows:
connect rcvcat rman11203/rman11203@recovery_catalogDB;
set dbid 896914363 ;
connect target
run {
set until time "to_date('04-DEC-2013 07:00:00','DD-MON-YYYY HH24:MI:SS')";
allocate channel t1 type 'SBT_TAPE'parms'ENV=(NB_ORA_CLIENT=XXXXXXXX)';
restore controlfile;
release channel t1;
}
Mount the database
Relational Database Consulting
Page 5
iii.)
Restore the datafiles:
Script:
connect target
run {
set until time "to_date('04-DEC-2013 07:00:00','DD-MON-YYYY HH24:MI:SS')";
allocate channel t1 type 'SBT_TAPE'parms'ENV=(NB_ORA_CLIENT=XXXXXXXX)';
allocate channel t2 type 'SBT_TAPE'parms'ENV=(NB_ORA_CLIENT=XXXXXXXX)';
restore datafile 1,2,3,23,53,16,17,18 ;
release channel t1;
release channel t2;
}
Output from running the above restore script:
Relational Database Consulting
Page 6
Relational Database Consulting
Page 7
Once the datafiles restore is completed, there are two options to recover and
open the database:
a.) Rman, (automatic recovery)
b.) Sqlplus (manual user managed)
Each of these has its own pros and cons. I will start with showing how to do it
using rman then sqlplus.
iv.)
Using rman to recover the database.
If you offline drop the datafiles that where not restored, then use rman to
recover the database you will get this error message:
RMAN-06094: datafile XX must be restored
To get around this problem you have to backup the controlfile to trace then edit
the controlfile trace to remove the unwanted datafiles (un-restored files)
To backup the controlfile to trace do:
SQL> alter database backup controlfile to trace as ‘/tmp/controlf.trc’ ;
Edit the controlfile trace and only leave the files that were restored. See sample
below.
STARTUP NOMOUNT
set echo on
CREATE CONTROLFILE REUSE DATABASE "CFMSP2" RESETLOGS ARCHIVELOG
MAXLOGFILES 30
MAXLOGMEMBERS 5
MAXDATAFILES 500
MAXINSTANCES 1
Relational Database Consulting
Page 8
MAXLOGHISTORY 37392
LOGFILE
GROUP 1 (
'+DATA/cfmsp2/onlinelog/group_1.307.777413909',
'+DATA/cfmsp2/onlinelog/group_1.359.825675081'
) SIZE 256M BLOCKSIZE 512,
GROUP 2 (
'+DATA/cfmsp2/onlinelog/group_2.308.777413975',
'+DATA/cfmsp2/onlinelog/group_2.358.825675085'
) SIZE 256M BLOCKSIZE 512,
GROUP 3 (
'+DATA/cfmsp2/onlinelog/group_3.309.777413985',
'+DATA/cfmsp2/onlinelog/group_3.357.825675091'
) SIZE 256M BLOCKSIZE 512,
GROUP 4 (
'+DATA/cfmsp2/onlinelog/group_4.340.825674989',
'+DATA/cfmsp2/onlinelog/group_4.360.825675017'
) SIZE 100M BLOCKSIZE 512,
GROUP 5 (
'+DATA/cfmsp2/onlinelog/group_5.305.777413729',
'+DATA/cfmsp2/onlinelog/group_5.356.825675093'
) SIZE 256M BLOCKSIZE 512
-- STANDBY LOGFILE
DATAFILE
'+DATA/cfmsp2/datafile/system.291.833377993',
'+DATA/cfmsp2/datafile/undots.292.833377991',
'+DATA/cfmsp2/datafile/sysaux.295.833374645',
'+DATA/cfmsp2/datafile/xsl_data.294.833374645',
'+DATA/cfmsp2/datafile/xsl_data.296.833374643',
'+DATA/cfmsp2/datafile/xsl_data.278.833376423',
'+DATA/cfmsp2/datafile/undots.293.833377919',
'+DATA/cfmsp2/datafile/undots.290.833380071'
CHARACTER SET AL32UTF8
;
Shutdown the oracle database and then execute the above script.
SQL> shutdown immediate
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL>@/tmp/controlf.trc
Controlfile created.
SQL> exit
Now that the controlfile has been created, it’s time to restore the archive logs
manually. This is so because the recently created control file does not any info
about backups of archivelogs generated prior to now! Otherwise if you try to
recover the database you will get this error message:
RMAN-06054: media recovery requesting unknown archived log for
thread 1 with sequence 282016 and starting SCN of 13166164699339
Relational Database Consulting
Page 9
connect target
run {
allocate channel t1 type 'SBT_TAPE';
allocate channel t2 type 'SBT_TAPE';
restore archivelog from logseq XXXXXX until logseq XXXXXX thread 1;
release channel t1;
release channel t2;
}
Once the restore of the archivelogs is completed, catalog the archive logs and
then you can go ahead and recover the database using the below recovery script:
connect target
run {
set until time "to_date('04-DEC-2013 02:35:00','DD-MON-YYYY HH24:MI:SS')";
allocate channel t1 type 'SBT_TAPE'parms'ENV=(NB_ORA_CLIENT=XXXXXXXX)';
allocate channel t2 type 'SBT_TAPE'parms'ENV=(NB_ORA_CLIENT=XXXXXXXX)';
recover database DELETE ARCHIVELOG MAXSIZE 10G ;
release channel t1;
release channel t2;
}
When recovery is complete you can open resetlogs your database!
Recovering Database using sqlplus.
To recover the database using sqlplus, you need to first restore the archivelogs
as shown above using rman.
Once the archive logs are restored then offline drop all the datafiles that were
not restored as shown below:
alter database datafile
alter database datafile
alter database datafile
alter database datafile
alter database datafile
alter database datafile
alter database datafile
alter database datafile
alter database datafile
4
offline drop
5
offline drop
6
offline drop
7
offline drop
8
offline drop
9
offline drop
10
offline drop
11
offline drop
……………………………..
;
;
;
;
;
;
;
;
;
Recover the database in sqlplus as follows:
SQL> recover database using backup controlfile until cancel ;
Relational Database Consulting
Page 10
ORA-00279: change 13166141511000 generated at 12/03/2013 01:30:16 needed for
thread 1
ORA-00289: suggestion :
/app/oracle/arch/cfmsp2/log/1_0000281991_748556524.cfmsp2
ORA-00280: change 13166141511000 for thread 1 is in sequence #281991
ORA-00278: log file '/app/oracle/arch/cfmsp2/log/1_0000281991_748556524.cfmsp2'
no longer needed for this recovery
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
v.)
Opening the Database Resetlogs
Now that the recovery is done, the database can be opened resetlogs.
SQL> alter database open resetlogs;
You are almost done! Time to create a directory for datapump
SQL> create directory exp_dir as ‘/app/oracle/export’ ;
Table Export:
Relational Database Consulting
Page 11
Finally this is how the database datafiles look like!
Relational Database Consulting
Page 12
Relational Database Consulting
Page 13
This is how a partial database restore is done.
Relational Database Consulting
Page 14