Subject: Re: Speed up Clog Access by increasing CLOG buffers
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To: pgsql-hackers <pgsql-hackers@postgresql.org>
From: Jesper Pedersen <jesper.pedersen@redhat.com>
Organization: JBoss, by Red Hat
Message-ID: <55FC4C33.1050903@redhat.com>
Date: Fri, 18 Sep 2015 13:38:59 -0400
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On 09/11/2015 10:31 AM, Amit Kapila wrote:
> Updated comments and the patch (increate_clog_bufs_v2.patch)
> containing the same is attached.
>

I have done various runs on an Intel Xeon 28C/56T w/ 256Gb mem and 2 x 
RAID10 SSD (data + xlog) with Min(64,).

Kept the shared_buffers=64GB and effective_cache_size=160GB settings 
across all runs, but did runs with both synchronous_commit on and off 
and different scale factors for pgbench.

The results are in flux for all client numbers within -2 to +2% 
depending on the latency average.

So no real conclusion from here other than the patch doesn't help/hurt 
performance on this setup, likely depends on further CLogControlLock 
related changes to see real benefit.

Best regards,
  Jesper


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