Re: rman Ora-4031 - how to flush large pool?

From: Tim Gorman <>
Date: Mon, 14 Jul 2008 22:02:35 -0600
Message-ID: <>


The text following the ORA-04031 error message often states what part of the SGA has run out of space (i.e. shared pool, large pool, etc).

The "Large Pool" essentially flushes itself all the time -- all data structures there are transient, and are deallocated/destroyed when no longer in active use. As a result, there is no ALTER SYSTEM FLUSH LARGE_POOL command. Query V$SGASTAT where POOL = 'large pool' to see what is present at any point in time. If the query returns no rows, then nothing is present there.

By the way, RMAN doesn't use the Large Pool unless some kind of inter-process communication is going on between backup channels and I/O channels (i.e. duplexed backups, etc). Unless you've specified duplexed backups, RMAN probably isn't using the Large Pool. Since RMAN is largely implemented through PL/SQL packages, it is likely that your ORA-04031 is occurring in the Shared Pool. Read the error message a little more closely...

Hope this helps...

Tim Gorman
consultant - Evergreen Database Technologies, Inc. P.O. Box 1802, Evergreen CO 80437-1802

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Douglas Cowles wrote:
> We have a system that is throwing ORA-4031's in rman archive log
> backups after the system has been up a few days. To my understanding,
> RMAN tries to use the large pool for it's activities. When we alter
> system flush shared pool - the errors do not stop - the database has
> to be bounced or the large_pool has to be increased 3M or so. Does
> alter system flush shared_pool flush the large pool? If it does, then
> why would that not defragment the pool? If it does not, is there a way
> to do it? In general, will flushing the shared_pool defragment it -
> large pool or otherwise?
> Thanks,
> Doug C.

Received on Mon Jul 14 2008 - 23:02:35 CDT

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