Re: Rollbacks online

From: Charlie Mengler <charliem_at_mwh.com>
Date: Fri, 02 Jun 2000 08:17:13 -0700
Message-Id: <10516.107563@fatcity.com>

I have just learned something that I did not know previously WRT to rollback segments. If/when a rollback segment has been created as a "PUBLIC" rollback segment, you do NOT need to specify it in the initSID.ora file to have it online once the instance restarts; at least under V8.1.6 as demonstrated below.

HTH & YMMV! SVRMGR> select segment_name , status from dba_rollback_segs

     2> /
SEGMENT_NAME                   STATUS          


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

SYSTEM                         ONLINE          
RBS0                           ONLINE          

2 rows selected.

SVRMGR> --CREATE TABLESPACE rollback
SVRMGR> --        DATAFILE '/db01/oracle/BCM/rollback.dbf' SIZE 128M
SVRMGR> --        DEFAULT STORAGE (INITIAL 4M
SVRMGR> --                        NEXT 4M 
SVRMGR> --                        MINEXTENTS 1
SVRMGR> --                        MAXEXTENTS 511
SVRMGR> --                        PCTINCREASE 0)
SVRMGR> --        ONLINE
SVRMGR> --/
SVRMGR> CREATE  PUBLIC ROLLBACK SEGMENT R01 
     2>         TABLESPACE rollback
     3>         STORAGE (
     4>                 INITIAL 128K
     5>                 MINEXTENTS 121
     6>                 MAXEXTENTS 8192
     7>                 NEXT 128K
     8>                 )
     9> /

Statement processed.

SVRMGR> CREATE  PUBLIC ROLLBACK SEGMENT R02 
     2>         TABLESPACE rollback
     3>         STORAGE (
     4>                 INITIAL 128K
     5>                 MINEXTENTS 121
     6>                 MAXEXTENTS 8192
     7>                 NEXT 128K
     8>                 )
     9> /

Statement processed.
SVRMGR> alter rollback segment r01 online

     2> /
Statement processed.
SVRMGR> alter rollback segment r02 online

     2> /
Statement processed.
SVRMGR> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SVRMGR> /
SVRMGR> startup
ORACLE instance started.

Total System Global Area                        351965168 bytes
Fixed Size                                          69616 bytes
Variable Size                                    80519168 bytes
Database Buffers                                271196160 bytes
Redo Buffers                                       180224 bytes

Database mounted.
Database opened.

SVRMGR> /
SVRMGR> select  segment_name , status  from dba_rollback_segs
     2> /
SEGMENT_NAME                   STATUS          


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

SYSTEM                         ONLINE          
RBS0                           ONLINE          
R01                            ONLINE          

Received on Fri Jun 02 2000 - 10:17:13 CDT