From: Tom Lane <tgl@sss.pgh.pa.us>
To: Oleg Lebedev <oleg.lebedev@waterford.org>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Slow query
Date: Mon, 24 Mar 2003 17:08:50 -0500
Message-ID: <20749.1048543730@sss.pgh.pa.us> (raw)
In-Reply-To: <993DBE5B4D02194382EC8DF8554A5273113E5F@postoffice.waterford.org>
References: <993DBE5B4D02194382EC8DF8554A5273113E5F@postoffice.waterford.org>
Oleg Lebedev <oleg.lebedev@waterford.org> writes:
> I just ran the query you sent me and attached the output of EXPLAIN
> ANALYZE as TOMs_plan.txt
> It did not speed up the query significantly.
Nope. I was hoping to see a faster-start plan, but given the number of
rows involved I guess it won't change its mind. You're going to have to
think about a more intelligent approach, rather than minor tweaks.
One question: since objectid is evidently a primary key, why are you
doing a subselect for the first part? Wouldn't it give the same result
just to say "m.activity = '347667'" in the top-level WHERE?
As for the second part, I think you'll have to try to rewrite it as a
join with the media table.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, oleg.lebedev@waterford.org
Subject: Re: Slow query
In-Reply-To: <20749.1048543730@sss.pgh.pa.us>
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