From: | <alvis(at)piladzi-2(dot)biz> |
---|---|
To: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Sorting a query on a view ignores an index |
Date: | 2003-08-22 10:11:19 |
Message-ID: | 001201c36895$bc9a9910$1401010a@Xeon |
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Thread: | |
Lists: | pgsql-performance |
Hello,
Here is my exp. regarding VIEW (create VIEW view_name AS SELECT ....)
optimization.
I have found strange (or at least not very intelligent) behavior of query
planner (v.7.3.4).
Given task is to take data from 14 tables, join, group, sort, etc. I
currently use about ten views referencing each other.
I have done a lot of job to adjust 'postgresql.conf' configuration.
Except common increase of shared_mem&buffer stuff I felt I was unable to do
anything else.
So, initialy, time to generate the Monthly report was about 10 sec.
I started to play with GEQO....
Screaming success -- I downplayed query execution time about 3x JUST by
setting geqo_threshold=3.
Now my Monthly report takes about 3 sec.
(Users are running that sequence of select queries (I call it invocation of
the final view ;-) quite often for any given period of time --
usually from one week to half a year (rarely) so it is essential part of my
dbvs.
Maybe my exp. will encourage somebody to play with scary genetic stuff. ;-)
Good luck & Best Regards,
Alvis
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