Re: User concurrency thresholding: where do I look? - Mailing list pgsql-performance

From Josh Berkus
Subject Re: User concurrency thresholding: where do I look?
Date
Msg-id 200707190922.24497.josh@agliodbs.com
Whole thread Raw
In response to Re: User concurrency thresholding: where do I look?  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: User concurrency thresholding: where do I look?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Alvaro,

> Have you messed with max_connections and/or max_locks_per_transaction
> while testing this?  The lock table is sized to max_locks_per_xact times
> max_connections, and shared memory hash tables get slower when they are
> full.  Of course, the saturation point would depend on the avg number of
> locks acquired per user, which would explain why you are seeing a lower
> number for some users and higher for others (simpler/more complex
> queries).

That's an interesting thought.  Let me check lock counts and see if this is
possibly the case.

--
Josh Berkus
PostgreSQL @ Sun
San Francisco

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