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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Don Seiler <don@seiler.us>
To: Vijaykumar Jain <vijaykumarjain.github@gmail.com>
Cc: pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: WALWriteLocks
Date: Wed, 05 May 2021 18:44:57 +0200
Message-ID: <6e8a24089781301efb1e06d0b0b0924439e10b4a.camel@cybertec.at> (raw)
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On Wed, 2021-05-05 at 11:25 -0500, Don Seiler wrote:
> What I want to know is if there are other events that would contribute
>  to a WALWriteLock (eg writing to a data file or the postgresql.log file)
>  or is it 100% writing to the WAL file.

You don't contribute to a lock...

The documentation says
(https://www.postgresql.org/docs/13/monitoring-stats.html#WAIT-EVENT-LOCK-TABLE):

> WALWrite 	Waiting for WAL buffers to be written to disk.

So it is contention while writing or flushing WAL.
You can read the code for the details.

Yours,
Laurenz Albe
-- 
Cybertec | https://www.cybertec-postgresql.com






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