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Home -> Community -> Mailing Lists -> Oracle-L -> Re: MLOG$ and RUPD$ tables are not analyzed
Hi, Luc
I had the same issue with MLOG$_* tables (with 10.1.0.4) and I logged an SR a year ago. The support could not find why dbms_stats.gather_schema_stats and dbms_stats.gather_database_stats does not work form MLOG$ tables. They advised me to use dbms_stats.gather_table_stats for MLOG$ tables. It is safe and it is working. MLOG$ tables have very strange behaviour. They have some VPD-like behaviour so that one log keeps data for many mviews. This is not explained in the docs in any way. In fact, MLOG$ have to be close-to-empty, if all mviews refresh fine. But if some mview is not refreshed for a log time (for example, there was a bug when you drop mview but it does not unregister form the log), the MLOG$ on master table can grow very big. This is the expected behaviour. Anyway, your statistics on MLOG$ tables will never be accurate. Maybe this is why dbms_stats.gather_database/schema_stats omit them. But without statistics on them, you can get tons of recursive SQLs for dynamic sampling in the shared pool. So you'd better use gather_table_stats and acquiesce that the stats are wrong.
-- Regards, Yavor Ivanov Senior Database Expert Stemo Ltd On Mon, 04 Jun 2007 22:39:59 +0300, Luc Demanche <lucdemanche_at_gmail.com> wrote:Received on Tue Jun 05 2007 - 09:45:18 CDT
> Hi,
>
> I'm using Oracle 10.1.
> Is it normal that all the tables MLOG$ and RUPD$ (associated to an
> materialized view) are not analyzed by DBMS_STATS ?
>
> Thanks
> Luc
>
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