8.1.6 hm.....
- "Johnston, Tim" <TJohnston_at_quallaby.com> wrote:
> Um... Must be version differences... Here is a test case I ran on
> my
> 8.1.7.3 machine...
>
> SQL> create public rollback segment tim tablespace rbs storage (
> initial 1M
> next 1M minextents 20 maxextents 100 optimal 20M );
>
> Rollback segment created.
>
> SQL> alter rollback segment tim online;
>
> Rollback segment altered.
>
> SQL> select segment_name, min_extents, initial_extent, next_extent
> 2 from dba_segments
> 3 where segment_name = 'TIM';
>
> SEGMENT_NAME MIN_EXTENTS INITIAL_EXTENT NEXT_EXTENT
> ------------------------------ ----------- -------------- -----------
> TIM 20 1048576 1048576
>
> SQL> select rs.extents, rs.rssize/1048576 , rs.optsize/1048576
> 2 from dba_rollback_segs drs,
> 3 v$rollstat rs
> 4 where drs.segment_name = 'TIM'
> 5 and drs.segment_id = rs.usn;
>
> EXTENTS RS.RSSIZE/1048576 RS.OPTSIZE/1048576
> ---------- ----------------- ------------------
> 20 20.296875 20
>
> SQL> alter rollback segment TIM shrink to 10M;
>
> Rollback segment altered.
>
> SQL> select segment_name, min_extents, initial_extent, next_extent
> 2 from dba_segments
> 3 where segment_name = 'TIM';
>
> SEGMENT_NAME MIN_EXTENTS INITIAL_EXTENT NEXT_EXTENT
> ------------------------------ ----------- -------------- -----------
> TIM 20 1048576 1048576
>
> SQL> select rs.extents, rs.rssize, rs.optsize
> 2 from dba_rollback_segs drs,
> 3 v$rollstat rs
> 4 where drs.segment_name = 'TIM'
> 5 and drs.segment_id = rs.usn;
>
> EXTENTS RSSIZE OPTSIZE
> ---------- ---------- ----------
> 10 10633216 20971520
>
> SQL> alter rollback segment tim offline;
>
> Rollback segment altered.
>
> SQL> drop rollback segment tim;
>
> Rollback segment dropped.
>
> SQL>
>
> What version is your test running on?
>
> Tim
>
> PS - Here is my test case if you want to run it...
>
> column segment_name format a30
> create public rollback segment tim tablespace rbs storage ( initial
> 1M next
> 1M minextents 20 maxextents 100 optimal 20M );
> alter rollback segment tim online;
> select segment_name, min_extents, initial_extent, next_extent
> from dba_segments
> where segment_name = 'TIM';
> select rs.extents, rs.rssize/1048576 , rs.optsize/1048576
> from dba_rollback_segs drs,
> v$rollstat rs
> where drs.segment_name = 'TIM'
> and drs.segment_id = rs.usn;
> alter rollback segment TIM shrink to 10M;
> select segment_name, min_extents, initial_extent, next_extent
> from dba_segments
> where segment_name = 'TIM';
> select rs.extents, rs.rssize, rs.optsize
> from dba_rollback_segs drs,
> v$rollstat rs
> where drs.segment_name = 'TIM'
> and drs.segment_id = rs.usn;
> alter rollback segment tim offline;
> drop rollback segment tim;
>
> -----Original Message-----
> Sent: Wednesday, January 30, 2002 2:17 PM
> To: Multiple recipients of list ORACLE-L
>
>
> testing....
>
> if the initial extent*min_extents is less than the optimal, yes you
> can
> shrink below optimal.
>
> if initial*minextents = optimal, you can execute an alter rollback
> segment statement that lists a shrink size that is less than optimal
> AND less than initial*minextents and it will not fail. But if you
> LOOK
> at the size it shrinks to, it's initial*minextents.
>
> so you can "kinda" shrink below optimal, the statement won't fail,
> but
> Oracle will ignore the number you give it.
>
>
> --- "Johnston, Tim" <TJohnston_at_quallaby.com> wrote:
> > You know what? I thought the same thing... But, the curious side
> of
> > me
> > decided to give it a try to be sure... And guess what... It
> works?
> > Learn
> > something new everyday...
> >
> > SQL> select segment_name,sum(bytes) from dba_segments where
> > tablespace_name
> > = 'RBS' and segment_name
> > = 'RBS17' group by segment_name;
> >
> > SEGMENT_NAME SUM(BYTES)
> > ------------------------ ----------
> > RBS17 22364160
> >
> >
> > SQL> select rs.optsize, rs.extents
> > 2 from dba_rollback_segs drs,
> > 3 v$rollstat rs
> > 4 where drs.segment_name = 'RBS17'
> > 5 and drs.segment_id = rs.usn;
> >
> > OPTSIZE EXTENTS
> > ---------- ----------
> > 22020096 21
> >
> > SQL> alter rollback segment RBS17 shrink to 10M;
> >
> > Rollback segment altered.
> >
> > SQL> select segment_name,sum(bytes) from dba_segments where
> > tablespace_name
> > = 'RBS' and segment_name
> > = 'RBS17' group by segment_name;
> >
> > SEGMENT_NAME SUM(BYTES)
> > ------------------------- ----------
> > RBS17 10649600
> >
> >
> > SQL> select rs.optsize, rs.extents
> > 2 from dba_rollback_segs drs,
> > 3 v$rollstat rs
> > 4 where drs.segment_name = 'RBS17'
> > 5 and drs.segment_id = rs.usn;
> >
> > OPTSIZE EXTENTS
> > ---------- ----------
> > 22020096 10
> >
> > SQL>
> >
> > 8.1.7.3 on Solaris 2.8
> >
> > Tim
> >
> > -----Original Message-----
> > Sent: Wednesday, January 30, 2002 10:26 AM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > no, you can't shrink a rollback segment below the optimal value
> >
> > --- Sinard Xing <sinardyxing_at_bcs-ach.com.sg> wrote:
> > > Hi,
> > >
> > >
> > > Assume
> > > INITIAL * MINEXTENT = 2M and also = OPTIMAL
> > >
> > > Do you think
> > > ALTER ROLLBACK SEGMENT rbs SHRINK TO 1M;
> > >
> > > will work ?
> > >
> > >
> > >
> > > Thanks,
> > >
> > > Sinardy
> > > --
>
=== message truncated ===
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Received on Wed Jan 30 2002 - 20:18:39 CST
