From: Tom Lane <tgl@sss.pgh.pa.us>
To: Merlin Moncure <merlin.moncure@rcsonline.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Finding bottleneck
Date: Mon, 22 Aug 2005 10:17:53 -0400
Message-ID: <15638.1124720273@sss.pgh.pa.us> (raw)
In-Reply-To: <6EE64EF3AB31D5448D0007DD34EEB3417DD15D@Herge.rcsinc.local>
References: <6EE64EF3AB31D5448D0007DD34EEB3417DD15D@Herge.rcsinc.local>
"Merlin Moncure" <merlin.moncure@rcsonline.com> writes:
> One thing that might interest you is that the penalty in 8.1 for
> stats_command_string=true in this type of access pattern is very high: I
> was experimenting to see if the new cpu efficiency gave me enough of a
> budget to start using this. This more than doubled the cpu load to
> around 70% with a runtime of 82 seconds. This is actually worse than
> 8.0 :(.
That seems quite peculiar; AFAICS the pgstat code shouldn't be any
slower than before. At first I thought it might be because we'd
increased PGSTAT_ACTIVITY_SIZE, but actually that happened before
8.0 release, so it shouldn't be a factor in this comparison.
Can anyone else confirm a larger penalty for stats_command_string in
HEAD than in 8.0? A self-contained test case would be nice too.
regards, tom lane
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, merlin.moncure@rcsonline.com
Subject: Re: Finding bottleneck
In-Reply-To: <15638.1124720273@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox