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From: Raj <rajeshkumar.dba09@gmail.com>
Date: Tue, 7 Oct 2025 10:22:47 +0530
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 <CAJk5AtbeY+O71bbESq1+rG3zqv=mPzEDaxMniXuBfjZ7+RKpaw@mail.gmail.com>
Subject: Re: Wal_keep_size
To: Thomas Carroll <tomfecarroll@yahoo.com>
Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
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If wal_keep_size is more than max_wal_size wouldn't it always trigger
checkpoint ?

On Tue, 7 Oct 2025, 03:08 Thomas Carroll, <tomfecarroll@yahoo.com> wrote:

> Hope nobody minds me chipping in here.
>
> The answer is "not necessarily."  The names make them seem closely
> related, but not so much.
>
> max_wal_size is all about *checkpoints*.  When the WAL exceeds this,
> Postgres will try to run a checkpoint.  Under some circumstances it won't,
> but let's keep it simple for now.
>
> wal_keep_size is all about *replication*.  Replicas need WAL files to
> stick around for long enough that they can process them.  wal_keep_size is
> a minimum figure.
>
> Tom
> On Monday, October 6, 2025 at 03:51:17 PM EDT, Raj <
> rajeshkumar.dba09@gmail.com> wrote:
>
>
> Should Wal_keep_size <= max_wal_size ?
>

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<div dir=3D"auto">If wal_keep_size is more than max_wal_size wouldn&#39;t i=
t always trigger checkpoint ?</div><br><div class=3D"gmail_quote gmail_quot=
e_container"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, 7 Oct 2025, 03:0=
8 Thomas Carroll, &lt;<a href=3D"mailto:tomfecarroll@yahoo.com">tomfecarrol=
l@yahoo.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><di=
v style=3D"font-family:Helvetica Neue,Helvetica,Arial,sans-serif;font-size:=
16px"><div></div>
        <div dir=3D"ltr">Hope nobody minds me chipping in here.</div><div d=
ir=3D"ltr"><br></div><div dir=3D"ltr">The answer is &quot;not necessarily.&=
quot;=C2=A0 The names make them seem closely related, but not so much.</div=
><div dir=3D"ltr"><br></div><div dir=3D"ltr">max_wal_size is all about <i>c=
heckpoints</i>.=C2=A0 When the WAL exceeds this, Postgres will try to run a=
 checkpoint.=C2=A0 Under some circumstances it won&#39;t, but let&#39;s kee=
p it simple for now.</div><div dir=3D"ltr"><br></div><div dir=3D"ltr">wal_k=
eep_size is all about <i>replication</i>.=C2=A0 Replicas need WAL files to =
stick around for long enough that they can process them.=C2=A0 wal_keep_siz=
e is a minimum figure.</div><div><br></div><div dir=3D"ltr">Tom</div>
       =20
        </div><div id=3D"m_4186013837168157399yahoo_quoted_0479540014">
            <div style=3D"font-family:&#39;Helvetica Neue&#39;,Helvetica,Ar=
ial,sans-serif;font-size:13px;color:#26282a">
               =20
                <div>
                        On Monday, October 6, 2025 at 03:51:17 PM EDT, Raj =
&lt;<a href=3D"mailto:rajeshkumar.dba09@gmail.com" target=3D"_blank" rel=3D=
"noreferrer">rajeshkumar.dba09@gmail.com</a>&gt; wrote:
                    </div>
                    <div><br></div>
                    <div><br></div>
               =20
               =20
                <div><div id=3D"m_4186013837168157399yiv6056229186"><div>Sh=
ould Wal_keep_size &lt;=3D max_wal_size ?</div>
</div></div>
            </div>
        </div></div></blockquote></div>

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