Re: A question about RBS
- From: Paul Drake <bdbafh@xxxxxxxxx>
- To: gmei@xxxxxxxxxx
- Date: Thu, 4 Nov 2004 16:41:05 -0500
Guang.
8.1.7.3. you're thinking about UNDO tablespaces in 9.2 and later.
8.1.7:
eventually, if you have OPTIMAL set, the inividual rollback segments
that are over their optimal setting will shrink. eventually.
This means that they will use free (or "freed") extents in the
tablespace, as in non-allocated.
This does not mean that they can de-allocate extents from a rollback segment.
Big difference.
9.2:
an undo segment can "steal" extents away from another undo segment.
(notice how I did not say "rollback segment" here?)
Paul
(gratuitous reminder about Oracle Security Alert #68 and de-support of
8.1.7 as of 31-DEC-2004 - patch/upgrade/migrate or .. DIE ... (or not)
exploit code to be released by NGS at the end of the month)
On Thu, 4 Nov 2004 16:24:22 -0500, Guang Mei <gmei@xxxxxxxxxx> wrote:
> Hi:
>
> Oralce 8173 on Sun box. RBSLMT size is 2G.
>
> First I got this when a delete statement was run. There was no any other
> transactions running during the whole thing.
>
> ORA-1650: unable to extend rollback segment RBS007 by 16 in
> tablespace RBSLMT
>
> Then I found:
>
> select segment_name, bytes from dba_segments where segment_name like 'RBS%';
>
> SEGMENT_NAME BYTES
> -------------------------------- ----------
> RBS001 119537664
> RBS002 96862208
> RBS003 237633536
> RBS004 89653248
> RBS005 762052608
> RBS006 371982336
> RBS007 354549760
> RBS008 115081216
>
> 8 rows selected.
>
> select sum(bytes) from dba_segments where segment_name like 'RBS%';
>
> SUM(BYTES)
> ----------
> 2147352576
>
> Now I did the delete again (use the largest rbs from above info):
>
> SQL> set transaction use rollback segment RBS005;
>
> Transaction set.
>
> SQL> delete from termhistory where historyid=19;
>
> 915798 rows deleted.
>
> SQL> commit;
>
> Commit complete.
>
> My question is why the "delete" worked this time? I thought one RBS will
> take over other RBS's space automatically if necessary. Since there is no
> other transactions going on, which ever RBS (picked up by the tsansaction)
> should not matter.
>
> Thanks.
>
> Guang
>
> --
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>
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