From: Sven Geisler <sgeisler@aeccom.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Lor <Robert.Lor@Sun.COM>
Cc: Tatsuo Ishii <ishii@sraoss.co.jp>
Cc: pgsql-hackers@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [HACKERS] Sun Donated a Sun Fire T2000 to the PostgreSQL
Date: Fri, 21 Jul 2006 16:59:49 +0200
Message-ID: <44C0EBE5.8010508@aeccom.com> (raw)
In-Reply-To: <21889.1153489365@sss.pgh.pa.us>
References: <20060617.101521.95879771.t-ishii@sraoss.co.jp>
<10226.1150511655@sss.pgh.pa.us>
<20060617.111838.39487910.t-ishii@sraoss.co.jp>
<20060713.180234.45872055.t-ishii@sraoss.co.jp>
<8669.1153422118@sss.pgh.pa.us>
<44C088C8.9050303@sun.com>
<21889.1153489365@sss.pgh.pa.us>
Hi,
Tom Lane schrieb:
> Robert Lor <Robert.Lor@Sun.COM> writes:
>> I ran pgbench and fired up a DTrace script using the lwlock probes we've
>> added, and it looks like BufMappingLock is the most contended lock, but
>> CheckpointStartLocks are held for longer duration!
>
> Those numbers look a bit suspicious --- I'd expect to see some of the
> LWLocks being taken in both shared and exclusive modes, but you don't
> show any such cases. You sure your script is counting correctly?
> Also, it'd be interesting to count time spent holding shared lock
> separately from time spent holding exclusive.
Is there a test case which shows the contention for this full cached
tables? It would be nice to have measurable numbers like context
switches and queries per second.
Sven.
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To: pgsql-performance@postgresql.org
Cc: sgeisler@aeccom.com, tgl@sss.pgh.pa.us, Robert.Lor@Sun.COM, ishii@sraoss.co.jp, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Sun Donated a Sun Fire T2000 to the PostgreSQL
In-Reply-To: <44C0EBE5.8010508@aeccom.com>
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