Re: Speed up Clog Access by increasing CLOG buffers

From: Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>
To: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Speed up Clog Access by increasing CLOG buffers
Date: 2015-09-18 17:38:59
Message-ID: 55FC4C33.1050903@redhat.com
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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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