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From: Fabrice Chapuis <fabrice636861@gmail.com>
Date: Fri, 29 Sep 2023 10:48:09 +0200
Message-ID: <CAA5-nLB5axGwwj6ft6G5tHxKqEC932M5k-4Ytb2W1iQziqmuLQ@mail.gmail.com>
Subject: Re: wal recycling problem
To: Christoph Moench-Tegeder <cmt@burggraben.net>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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Yes, barman replication can keep up with primary, wals segments size are
under max_wal_size (24Gb in our configuration)

Here is  pg_replication_slots view:

barman_ge      physical  f          t            39409 1EE2/49000000
reserved    f
barman_be      physical  f          t            39434 1EE2/3D000000
reserved    f

on the other hand there are 2 slots for logical replication which display
status extended. I don't understand why given that the confirmed_flush_lsn
field that is up to date. The restart_lsn remains frozen, for what reason?

pgoutput =E2=94=82 logical   =E2=94=82 2667915 =E2=94=82 db019a00 =E2=94=82=
 f         =E2=94=82 t      =E2=94=82    1880162
=E2=94=82      =E2=94=82     68512101 =E2=94=82 1ECA/37C3F1B8 =E2=94=82 1EE=
2/4D6BDCF8       =E2=94=82 extended   =E2=94=82
             =E2=94=82 f         =E2=94=82
pgoutput =E2=94=82 logical   =E2=94=82 2668584 =E2=94=82 db038a00 =E2=94=82=
 f         =E2=94=82 t      =E2=94=82
 363230  =E2=94=82      =E2=94=82     68512101 =E2=94=82 1ECA/37C3F1B8 =E2=
=94=82 1EE2/4D6BDCF8       =E2=94=82
extended   =E2=94=82               =E2=94=82 f         =E2=94=82

Regards
Fabrice

On Thu, Sep 28, 2023 at 7:59=E2=80=AFPM Christoph Moench-Tegeder <cmt@burgg=
raben.net>
wrote:

> ## Fabrice Chapuis (fabrice636861@gmail.com):
>
> > We have a cluster of 2 members (1 primary and 1 standby) with Postgres
> > version 14.9 and 2 barman server, slots are only configured for barman,
> > barman is version 3.7.
>
> The obvious question here is: can both of those barmans keep up with
> your database, or are you seeing WAL retention due to exactly these
> replication slots? (Check pg_replication_slots).
>
> Regards,
> Christoph
>
> --
> Spare Space
>

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr">Yes, ba=
rman replication can keep up with primary, wals segments size are under max=
_wal_size (24Gb in our configuration)</div><div dir=3D"ltr"><br></div><div =
dir=3D"ltr">Here is=C2=A0 pg_replication_slots view:</div><div dir=3D"ltr">=
<br><div><div>barman_ge=C2=A0 =C2=A0 =C2=A0 physical=C2=A0 f=C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 t=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 39409 1EE2/=
49000000=C2=A0 reserved=C2=A0 =C2=A0 f=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0</d=
iv><div>barman_be=C2=A0 =C2=A0 =C2=A0 physical=C2=A0 f=C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 t=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 39434 1EE2/3D00000=
0 reserved=C2=A0 =C2=A0 f=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0</div></div><div=
><br></div><div><div>on the other hand there are 2 slots for logical replic=
ation which display status extended. I don&#39;t understand why given that =
the confirmed_flush_lsn field that is up to date. The restart_lsn remains f=
rozen, for what reason?</div><div><br></div><div><div>pgoutput =E2=94=82 lo=
gical=C2=A0 =C2=A0=E2=94=82 2667915 =E2=94=82 db019a00 =E2=94=82 f=C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=94=82 t=C2=A0 =C2=A0 =C2=A0 =E2=94=82=C2=A0 =
=C2=A0 1880162 =E2=94=82=C2=A0 =C2=A0 =C2=A0 =E2=94=82=C2=A0 =C2=A0 =C2=A06=
8512101 =E2=94=82 1ECA/37C3F1B8 =E2=94=82 1EE2/4D6BDCF8=C2=A0 =C2=A0 =C2=A0=
 =C2=A0=E2=94=82 extended=C2=A0 =C2=A0=E2=94=82=C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=94=82 f=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=
=94=82</div><div>pgoutput =E2=94=82 logical=C2=A0 =C2=A0=E2=94=82 2668584 =
=E2=94=82 db038a00 =E2=94=82 f=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=94=82 t=
=C2=A0 =C2=A0 =C2=A0 =E2=94=82=C2=A0 =C2=A0 =C2=A0363230=C2=A0 =E2=94=82=C2=
=A0 =C2=A0 =C2=A0 =E2=94=82=C2=A0 =C2=A0 =C2=A068512101 =E2=94=82 1ECA/37C3=
F1B8 =E2=94=82 1EE2/4D6BDCF8=C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=94=82 extended=
=C2=A0 =C2=A0=E2=94=82=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0=E2=94=82 f=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=E2=94=82</div></div><div><=
br></div><div>Regards</div><div>Fabrice</div></div></div></div></div></div>=
<br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Thu=
, Sep 28, 2023 at 7:59=E2=80=AFPM Christoph Moench-Tegeder &lt;<a href=3D"m=
ailto:cmt@burggraben.net">cmt@burggraben.net</a>&gt; wrote:<br></div><block=
quote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1=
px solid rgb(204,204,204);padding-left:1ex">## Fabrice Chapuis (<a href=3D"=
mailto:fabrice636861@gmail.com" target=3D"_blank">fabrice636861@gmail.com</=
a>):<br>
<br>
&gt; We have a cluster of 2 members (1 primary and 1 standby) with Postgres=
<br>
&gt; version 14.9 and 2 barman server, slots are only configured for barman=
,<br>
&gt; barman is version 3.7.<br>
<br>
The obvious question here is: can both of those barmans keep up with<br>
your database, or are you seeing WAL retention due to exactly these<br>
replication slots? (Check pg_replication_slots).<br>
<br>
Regards,<br>
Christoph<br>
<br>
-- <br>
Spare Space<br>
</blockquote></div>

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