Re: Very slow queries - please help
От | Bealach-na Bo |
---|---|
Тема | Re: Very slow queries - please help |
Дата | |
Msg-id | BAY101-F3653633E9198EAC5BDA20BAD460@phx.gbl обсуждение исходный текст |
Ответ на | Re: Very slow queries - please help ("Thomas F. O'Connell" <tfo@sitening.com>) |
Список | pgsql-performance |
Thanks very much - there are a lot of good articles there... Reading as fast as I can :) Best, Bealach >From: "Thomas F. O'Connell" <tfo@sitening.com> >To: Bealach-na Bo <bealach_na_bo@hotmail.com> >CC: PgSQL - Performance <pgsql-performance@postgresql.org> >Subject: Re: [PERFORM] Very slow queries - please help >Date: Sun, 4 Dec 2005 00:40:01 -0600 > > >On Nov 24, 2005, at 12:14 PM, Bealach-na Bo wrote: > >>The consensus seems to be that I need more indexes and I also need to >>look into the NOT IN statement as a possible bottleneck. I've >>introduced the indexes which has led to a DRAMATIC change in response >>time. Now I have to experiment with INNER JOIN -> OUTER JOIN >>variations, SET ENABLE_SEQSCAN=OFF. >> >>Forgive me for not mentioning each person individually and by name. >>You have all contributed to confirming what I had suspected (and >>hoped): that *I* have a lot to learn! >> >>I'm attaching table descriptions, the first few lines of top output >>while the queries were running, index lists, sample queries and >>EXPLAIN ANALYSE output BEFORE and AFTER the introduction of the >>indexes. As I said, DRAMATIC :) I notice that the CPU usage does not >>vary very much, it's nearly 100% anyway, but the memory usage drops >>markedly, which is another very nice result of the index introduction. >> >>Any more comments and tips would be very welcome. > >You might find the following resources from techdocs instructive: > >http://techdocs.postgresql.org/redir.php?link=/techdocs/ >pgsqladventuresep2.php > >http://techdocs.postgresql.org/redir.php?link=/techdocs/ >pgsqladventuresep3.php > >These documents provide some guidance into the process of index selection. >It seems like you could still stand to benefit from more indexes based on >your queries, table definitions, and current indexes. > >-- >Thomas F. O'Connell >Database Architecture and Programming >Co-Founder >Sitening, LLC > >http://www.sitening.com/ >110 30th Avenue North, Suite 6 >Nashville, TN 37203-6320 >615-260-0005 (cell) >615-469-5150 (office) >615-469-5151 (fax) > >---------------------------(end of broadcast)--------------------------- >TIP 2: Don't 'kill -9' the postmaster
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