From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of
slapo@centrum.sk
Sent: Wednesday, August 07, 2013 8:43 AM
To: Pavel Stehule
Cc: pgsql-performance@postgresql.org
Subject: [PERFORM] Re: [PERFORM] Sub-optimal plan for a paginated query on a view with another view inside of it.
Good day,
I have included a link to the result of EXPLAIN ANALYZE. It's this one:
https://app.box.com/s/u8nk6qvkjs4ae7l7dh4h
Here's a link to Depesz's explain (if links to the site are okay):
http://explain.depesz.com/s/gCk
I have just tried setting geqo_threshold, join_collapse_limit and from_collapse_limit to 16, but it yielded no
improvement.
Changing those three parameters to 32 did speed up the query from about 3.3 seconds to about a second (give or take 50
ms),which is a pretty good improvement, but not quite there, as I'm looking to bring it down to about 300 ms if
possible.Changing those three settings to 48 yielded no improvements over 32.
Is there possibly something something else to tweak there?
Here's EXPLAIN ANALYZE output when the three settings have been set to 32:
http://explain.depesz.com/s/cj2
Thank you.
Peter Slapansky
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Your last explain analyze (with 3 settings set to 32) shows query duration 10ms, not 1sec.
Am I wrong?
Regards,
Igor Neyman