Hey all,

Fighting with a lot of ORA-1555s lately on 8.1.7.4 on HP/UX.  Most of them
are now coming from long-running Business Objects (B.O.) queries against our
OLTP DB.  I think I need to recreate the RBS tablespace (currently 1MB
extents in LMT), but until I can get time to do that, I'd like to approach
this from the application side, where I think the majority of the problem is
occurring.  I've been tracking TPM based on "user commits" in V$SYSSTAT and
we spiked at 20K TPM just before the B.O. query in question ORA-1555'd.
>From STATSPACK reports, I think the most likely cause for this is a COMMIT
for every DML in a batch job.  From what I've read, including MetaLink
40689.1, this over committing is one potential cause of ORA-1555s.

In order to narrow down the problem, I've turned on event 1555 in the
instance.  Is it possible to determine what table(s)' DML is causing the
ORA-1555 based on the trace file?  I have the last wait state, which happens
to be "db file sequential read", but I don't know if there's any
correlation.  If there is, I should be able to determine which table by the
file# and block# given in the trace.  Is this correct?

Also, if the over-committing process is not doing any DML on the tables of
the B.O. query, is it still a possible suspect of causing the ORA-1555
because of the potential of overwriting another process' RBS?

Damn.  I was hoping to be at 9i before I had to deal with RBSs...  :)


Rich

Rich Jesse                        System/Database Administrator
[EMAIL PROTECTED]           Quad/Tech International, Sussex, WI USA
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