Re: DBMS_STATS cannot analyze clusters

From: John Hurley <>
Date: Fri, 8 Apr 2011 06:50:14 -0700 (PDT)
Message-ID: <>


# I have 3 tables which are always queried together and joined on the same key. The common wisdom tells me that an index cluster is adequate for such situation. The performance of the application did improve as a result. The problem is with analyzing the cluster. DBMS_STATS cannot do that:

I think the phrase "common wisdom" involving creating a cluster is stretching it a bit. I have been around the block quite a while and believe me clusters are pretty uncommon. Some authors talk about using them and do recommend them for certain situations but in the universe of people designing custom systems ... not often considered AFAIK. There is a whole set of history involving stats on clusters that for the most part I am only vaguely aware of. It is probably release dependent how well dbms_stats works with clusters and may also have some issues with stats in parallel?

Do you have any monitoring in place that looks for objects that have old statistics? Depending on the philosophy that you have in place for when and if stats are gathered ( or not ) some tweaks to the monitoring and exception reporting process could be looked at. Received on Fri Apr 08 2011 - 08:50:14 CDT

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