Re: Persistent Plan Cache - Mailing list pgsql-performance

From Tom Lane
Subject Re: Persistent Plan Cache
Date
Msg-id 2971.1252863925@sss.pgh.pa.us
Whole thread Raw
In response to Persistent Plan Cache  (Joshua Rubin <jrubin@esoft.com>)
Responses Re: Persistent Plan Cache  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Re: Persistent Plan Cache  (Joshua Rubin <jrubin@esoft.com>)
List pgsql-performance
Joshua Rubin <jrubin@esoft.com> writes:
> We have a very large, partitioned, table that we often need to query
> from new connections, but frequently with similar queries. We have
> constraint exclusion on to take advantage of the partitioning. This also
> makes query planning more expensive. As a result, the CPU is fully
> loaded, all the time, preparing queries, many of which have been
> prepared, identically, by other connections.

If you're depending on constraint exclusion, it's hard to see how plan
caching could help you at all.  The generated plan needs to vary
depending on the actual WHERE-clause parameters.

            regards, tom lane

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