From: Jignesh K. Shah <J.K.Shah@Sun.COM>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org, Gregory Stark <stark@enterprisedb.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] 8.3beta1 testing on Solaris
Date: Fri, 26 Oct 2007 09:36:53 -0400
Message-ID: <4721ED75.7090607@sun.com> (raw)
In-Reply-To: <2139.1193369168@sss.pgh.pa.us>
References: <4720FB72.8060800@sun.com>
<871wbi95nb.fsf@oxford.xeocode.com>
<29721.1193359867@sss.pgh.pa.us>
<200710251956.56744.josh@agliodbs.com>
<2139.1193369168@sss.pgh.pa.us>
I agree with Tom.. somehow I think increasing NUM_CLOG_BUFFERS is just
avoiding the symptom to a later value.. I promise to look more into it
before making any recommendations to increase NUM_CLOG_BUFFERs.
Because though "iGen" showed improvements in that area by increasing
num_clog_buffers , EAStress had shown no improvements.. Plus the reason
I think this is not the problem in 8.3beta1 since the Lock Output
clearly does not show CLOGControlFile as to be the issue which I had
seen in earlier case. So I dont think that increasing NUM_CLOG_BUFFERS
will change thing here.
Now I dont understand the code pretty well yet I see three hotspots and
not sure if they are related to each other
* ProcArrayLock waits - causing Waits as reported by
83_lockwait.d script
* SimpleLRUReadPage - causing read IOs as reported by
iostat/rsnoop.d
* GetSnapshotData - causing CPU utilization as reported by hotuser
But I will shut up and do more testing.
Regards,
Jignesh
Tom Lane wrote:
> Josh Berkus <josh@agliodbs.com> writes:
>
>> Actually, 32 made a significant difference as I recall ... do you still have
>> the figures for that, Jignesh?
>>
>
> I'd want to see a new set of test runs backing up any call for a change
> in NUM_CLOG_BUFFERS --- we've changed enough stuff around this area that
> benchmarks using code from a few months back shouldn't carry a lot of
> weight.
>
> regards, tom lane
>
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To: pgsql-performance@postgresql.org
Cc: J.K.Shah@Sun.COM, tgl@sss.pgh.pa.us, josh@agliodbs.com, stark@enterprisedb.com, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] 8.3beta1 testing on Solaris
In-Reply-To: <4721ED75.7090607@sun.com>
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