This sounds similar to a known bug with ASSM tablespaces. The stats job
updates tables in SYSAUX. Those tables have indexes and up to 10.2.0.2 if
an instance does massive DML (which the stats job does in our case.
Terabyte oltp with daily data loads and many schemas) on segments in an ASSM
tablespace that has indexes, the undo is unbelievable. In our case it
produces 10x the undo / redo it normally would. It can cause not onlyora-1555
, but you can blow out the max extents (32767) for an undo segment.
The 'workaround' of coalescing the indexes prior to running such DML is only
minimally effective. The backport patch for previous versions in some cases
flat doesn't work (I know from experience.) The only sure fix is to upgrade
to 10.2.0.2, which I am told definitely fixes the issue, and which I am
preparing to do on several production instances even thought I HATE applying
the latest patchset (hornet's nest). Of course, if you are already on
10.2.0.2 and are seeing this, please let me know!
On Behalf Of Alex Gorbachev
Sent: Tuesday, June 27, 2006 2:52 PM
Subject: Re: ORA-01555
: snapshot too old: rollback segment number 24 with
name "_SYSSMU24$" too small
Duration 1151404820? That's like 36+ years... a bit odd, uh? :)
is often thrown regardless space availability in UNDO
tablespace. You can get it any time for read only transaction (or
single select) after it's running for retention_period time. Select
requires read consistent image of blocks and those are reconstructed
from UNDO info. UNDO info is kept for undo retention period. As soon
as you reach it - chances are you hit ORA-1555
on any more or less
often updatable table.
And yet another reason to delete this infamous job ASAP!
2006/6/27, arul kumar <arul76_2000@(protected)>:
> I have this recent error in alert log coming from the
> stats update job. Though the SQL is given partly, not
> able to find the EXACT database object that had
> problem. Any clue?
> Tue Jun 27 03:40:20 2006
caused by SQL statement below (Query
> Duration=1151404820 sec, SCN: 0x0849.81c92aa1):