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Re: Almost infinite query -> Different Query Plan when changing where clause value - Mailing list pgsql-performance

From Kevin Grittner
Subject Re: Almost infinite query -> Different Query Plan when changing where clause value
Date
Msg-id 4B790387020000250002F2CF@gw.wicourts.gov
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Responses Re: Almost infinite query -> Different Query Plan when changing where clause value  (lionel duboeuf <lionel.duboeuf@boozter.com>)
Re: Almost infinite query -> Different Query Plan when changing where clause value  (lionel duboeuf <lionel.duboeuf@boozter.com>)
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lionel duboeuf  wrote:
> Kevin Grittner a écrit :

>> I just reread your original email, and I'm not sure I understand
>> what you meant regarding VACUUM ANALYZE. If you run that right
>> beforehand, do you still get the slow plan for user 10?

> I confirm by executing manual "VACUUM ANALYZE" that the problem is
> solved.  But what i don't understand is that i would expect
> autovacuum to do the job.

I think this is the crux of the issue.  Boosting the
default_statistics_target or the statistics target for specific
columns might help, reducing autovacuum_analyze_scale_factor might
help, but I can't help wondering whether you inserted a large number
of rows for user 10 and then ran the query to select user 10 before
autovacuum had time to complete.  Does that seem possible?

-Kevin

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