Message-ID: <5A2042CD.3090006@nrc-cnrc.gc.ca>
Date: Thu, 30 Nov 2017 09:41:33 -0800
From: ghiureai <isabella.ghiurea@nrc-cnrc.gc.ca>
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To: pgsql-admin@lists.postgresql.org
Subject: Re: PG 10 streaming replication pg_wal question
References: <5A203DC7.40509@nrc-cnrc.gc.ca>
 <1512063321.2328.20.camel@cybertec.at>
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Thank you Laurenz,
can I  run a checkpoint manually in master host than ?


  On 11/30/2017 09:35 AM, Laurenz Albe wrote:
> ghiureai wrote:
>> I am testing PG10 streaming replication ,  with archiving off, I have
>> pg_wal on separate directory  to monitor the growth , I had the slave
>> offline yesterday  for  more than 20h while I was restoring one of db
>> (60GB) with pg_restore from a backup taken with pg_dump, today I brought
>> the slave PG host online and replication catch up  nicely , master and
>> slave are in sync now, but  on master host the pg_wal is still same
>> large size ( as yesterday)  even after all the wal files had been
>> applied to salve, would replication process not suppose to removed the
>> wal files  on master after being applied to salve ?
>> ( do I need to manually implement a cleanup job of this wal files, as
>> mentioned archiving is off on  both servers)
> Never remove WAL files yourself.
>
> pg_wal will shrink eventually.
> At the next checkpoint, PostgreSQL will remove all WAL files
> that were completed and archived successfully since the
> previous checkpoint, thus reducing WAL size a little.
>
> If there is activity on the databases, pg_wal will eventually
> shrink back to max_wal_size.
>
> Yours,
> Laurenz Albe
>