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From: Tom Lane <tgl@sss.pgh.pa.us>
To: tv@fuzzy.cz
Cc: Humair Mohammed <humairm@hotmail.com>
Cc: pavel.stehule@gmail.com
Cc: pgsql-performance@postgresql.org
Subject: Re: Query Performance SQL Server vs. Postgresql
Date: Sun, 21 Nov 2010 12:16:01 -0500
Message-ID: <22586.1290359761@sss.pgh.pa.us> (raw)
In-Reply-To: <3ba1d0462bc7df1c3eb5a6d4777ce08a.squirrel@sq.gransy.com>
References: <COL115-W5250BF8BDC50E0A64DABE4A8360@phx.gbl>
	<AANLkTin+MPhrYUzkCZjdAMLhF3KKZCCuvDm0=Npf9jz7@mail.gmail.com>
	<COL115-W3987D9D7DE908C5C47792DA8380@phx.gbl>
	<AANLkTi=yFV69yNZpHzKiZRtZ0X0PtKcpOrMNNkAo+Si6@mail.gmail.com>
	<COL115-W186A7B93051E6907958ED6A8380@phx.gbl>
	<AANLkTinQmaQ5Ui-vQwfqWFtOTCj76NWFBr6VDKMdVUCs@mail.gmail.com>
	<COL115-W6193714B75A26E58EA773AA83C0@phx.gbl>
	<3ba1d0462bc7df1c3eb5a6d4777ce08a.squirrel@sq.gransy.com>

tv@fuzzy.cz writes:
>> Second, I modified the work_mem setting to 2GB (reloaded config) and I see
>> a response time of 38 seconds. Results below from EXPLAIN ANALYZE:

> How did you reload the config? Using 'kill -HUP pid'? That should work
> fine. Have you cheched 'work_mem' after the reload?

> Because the explain plans are exactly the same (structure, estimated
> costs). The really interesting bit is this and it did not change at all

>    Buckets: 1024 Batches: 64  Memory Usage: 650kB

If that didn't change, I'm prepared to bet that the OP didn't actually
manage to change the active value of work_mem.

			regards, tom lane



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