Re: BUG #9635: Wal sender process is using 100% CPU - Mailing list pgsql-bugs

From Jamie Koceniak
Subject Re: BUG #9635: Wal sender process is using 100% CPU
Date
Msg-id 84CE67AB46ACDA41B18094177DD0853D212F58@ORD2MBX04C.mex05.mlsrvr.com
Whole thread Raw
In response to Re: BUG #9635: Wal sender process is using 100% CPU  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-bugs
Hi Andres,

The ssl option is on in postgres.conf but we don't have any hostssl lines o=
r cert configured as an authentication method in our pg_hba.conf file.

In our pg_hba.conf we have configured each replication host as trust:
host    replication     all             xx.xxx.xxx.xx/32        trust

I replied in a previous email that we have a job that inserts 30+ million r=
ecords into a table.
During the loading of this table, the wal_sender cpu spikes to 100% and app=
ears to stay at 100% until the replication is completed on the slave.
I have been able to reproduce this.  Other than offloading this job, is the=
re anything we can do to improve the replication lag?

Thanks!

-----Original Message-----
From: Andres Freund [mailto:andres@2ndquadrant.com]=20
Sent: Tuesday, May 06, 2014 3:42 PM
To: Jamie Koceniak
Cc: pgsql-bugs@postgresql.org
Subject: Re: [BUGS] BUG #9635: Wal sender process is using 100% CPU

Hi,

On 2014-03-19 17:13:56 +0000, jkoceniak@mediamath.com wrote:
> Periodically throughout the day, we keep seeing the wal sender process=20
> utilize 100% of the CPU. We began noticing this after we added 2 new=20
> slave servers, going from 2 to 4 slaves. See top results and I also=20
> included our wal settings. Thanks!

A typical reason for this is that the standbys are connecting over ssl. Is =
that the case? If so, intentionally?

Greetings,

Andres Freund

--=20
 Andres Freund                       http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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