From: Christophe Pettus <xof@thebuild.com>
To: sit7602@gmail.com, PostgreSQL Bug List <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #18724: High data disk utilization during log writing
Date: Mon, 25 Nov 2024 06:47:23 -0800
Message-ID: <9B2DED60-3C47-48A2-9F59-392749D820F1@thebuild.com> (raw)
In-Reply-To: <18724-1715b6dccdce4624@postgresql.org>
References: <18724-1715b6dccdce4624@postgresql.org>
> On Nov 25, 2024, at 04:26, PG Bug reporting form <noreply@postgresql.org> wrote:
> The lsof utility did not help in investigating this problem, as did
> restarting the server
> Setting log_min_duration_statement = -1 shows a significant decrease in the
> load on the data disk
> So I can't assume why data disk (/dev/vdb1 /data) utilized up to 60-80%
> while statements are logged to separate block device (/dev/vdc1
> /var/log/postgresql) and need some help to get off the ground
The question seems to answer itself here: You are logging every statement to the text logs, and it is very likely that the lines in the text log are larger than the actual data for that statement being written to the data disk. It can be very expensive to log every statement, especially when you have a significant query load (which you do here).
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To: pgsql-bugs@postgresql.org
Cc: xof@thebuild.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18724: High data disk utilization during log writing
In-Reply-To: <9B2DED60-3C47-48A2-9F59-392749D820F1@thebuild.com>
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