From: Carlo Stonebanks <stonec.register@sympatico.ca>
To: pgsql-performance@postgresql.org
Subject: Re: Is Vacuum/analyze destroying my performance?
Date: Mon, 4 Dec 2006 12:08:42 -0500
Message-ID: <el1kmi$t75$1@news.hub.org> (raw)
References: <el0av7$1a6l$1@news.hub.org>
<el0ctq$1g1i$1@news.hub.org>
<45743240.7050302@zeut.net>
""Matthew O'Connor"" <matthew@zeut.net> wrote in message
news:45743240.7050302@zeut.net...
> Just a wild guess, but the performance problem sounds like maybe as your
> data changes, eventually the planner moves some query from an index scan
> to a sequential scan, do you have any details on what queries are taking
> so long when things are running slow? You can turn on the GUC var
> "log_min_duration_statement" and see what queries are slow and then
> manually check them with an explain analyze, that might help.
>
> Matt
This is pretty well what I think is happening - I expect all queries to
eventually move from seq scans to index scans. I actually have a SQL logging
opion built into the import app.
I just can't figure out how the planner can be so wrong. We are running a 4
CPU server (two dual core 3.2 GHz Xeons) with 4GB RAM and Windows Server
2003 x64 and a PERC RAID subsystem (I don't know the RAID type). I know that
the metrics for the planner can be changed - is the default config for
postgesql not suitable for our setup? For this server, we would like to be
optimised for high speed over a few connections, rather than the classic
balanced speed over many connections.
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To: pgsql-performance@postgresql.org
Cc: stonec.register@sympatico.ca
Subject: Re: Is Vacuum/analyze destroying my performance?
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