Re: BUG #18724: High data disk utilization during log writing - Mailing list pgsql-bugs

From Christophe Pettus
Subject Re: BUG #18724: High data disk utilization during log writing
Date
Msg-id 9B2DED60-3C47-48A2-9F59-392749D820F1@thebuild.com
Whole thread Raw
In response to BUG #18724: High data disk utilization during log writing  (PG Bug reporting form <noreply@postgresql.org>)
Responses Re: BUG #18724: High data disk utilization during log writing
List pgsql-bugs

> 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
thelines in the text log are larger than the actual data for that statement being written to the data disk.  It can be
veryexpensive to log every statement, especially when you have a significant query load (which you do here). 


pgsql-bugs by date:

Previous
From: PG Bug reporting form
Date:
Subject: BUG #18724: High data disk utilization during log writing
Next
From: Tom Lane
Date:
Subject: Re: BUG #18722: Processing arrays with plpgsql raises errors