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From: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Date: Mon, 30 Mar 2026 01:46:36 +0530
Message-ID: 
 <CAFC+b6pO44=zGqwijzrcyGGTYCM51Y7zS5uQX0_nWjsxW9i3QQ@mail.gmail.com>
Subject: Re: Introduce XID age based replication slot invalidation
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>,
	SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>,
	"Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
 John H <johnhyvr@gmail.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
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Hello,

Thanks for the v5 patch set, I have reviewed and did initial testing on
v5 patch set, and it LGTM, except these

diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 286f0f46341..c2ff7e464f0 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1849,7 +1849,7 @@
ReportSlotInvalidation(ReplicationSlotInvalidationCause cause,
                                else
                                {
                                        /* translator: %s is a GUC variable
name */
-                                       appendStringInfo(&err_detail,
_("The slot's xmin %u is %d transactions old, which exceeds the configured
\"%s\" value of %d."),
+                                       appendStringInfo(&err_detail,
_("The slot's catalog_xmin %u is %d transactions old, which exceeds the
configured \"%s\" value of %d."),

 catalog_xmin, (int32) (recentXid - catalog_xmin), "max_slot_xid_age",
max_slot_xid_age);
                                }

while testing the active slot XID age invalidation (SIGTERM path) , i
observed that slot got invalidated , walsender was killed because of
SIGTERM , then starts the infinite-retry-cycle problem where
walreceiver starts walsender and walsender will try to use an invalidated
slot and dies, will think more on this.

-- 
Thanks,
Srinath Reddy Sadipiralla
EDB: https://www.enterprisedb.com/

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Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div dir=3D"ltr">Hello,</div><div><br>Thanks for the v5 pa=
tch set, I have reviewed=C2=A0and did initial testing on<br>v5 patch set, a=
nd it LGTM, except these <br><br>diff --git a/src/backend/replication/slot.=
c b/src/backend/replication/slot.c<br>index 286f0f46341..c2ff7e464f0 100644=
<br>--- a/src/backend/replication/slot.c<br>+++ b/src/backend/replication/s=
lot.c<br>@@ -1849,7 +1849,7 @@ ReportSlotInvalidation(ReplicationSlotInvali=
dationCause cause,<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 else<br>=C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 {<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 /* translator: %s is a GUC variable name */<br>=
- =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 appendStringInf=
o(&amp;err_detail, _(&quot;The slot&#39;s xmin %u is %d transactions old, w=
hich exceeds the configured \&quot;%s\&quot; value of %d.&quot;),<br>+ =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 appendStringInfo(&a=
mp;err_detail, _(&quot;The slot&#39;s catalog_xmin %u is %d transactions ol=
d, which exceeds the configured \&quot;%s\&quot; value of %d.&quot;),<br>=
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0catalog_xmin, (int32) (recentXid - ca=
talog_xmin), &quot;max_slot_xid_age&quot;, max_slot_xid_age);<br>=C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 }<br><br>while testing the active slot XID age =
invalidation (SIGTERM path) , i=C2=A0<br>observed that slot got invalidated=
 , walsender was killed because of<br>SIGTERM , then starts the infinite-re=
try-cycle problem where<br>walreceiver starts walsender and walsender will =
try to use an invalidated<br>slot and dies, will think=C2=A0more on this.<b=
r></div><div><br></div><span class=3D"gmail_signature_prefix">-- </span><br=
><div dir=3D"ltr" class=3D"gmail_signature"><div dir=3D"ltr"><span style=3D=
"color:rgb(34,34,34)">Thanks,</span><br style=3D"color:rgb(34,34,34)"><span=
 style=3D"color:rgb(34,34,34)">Srinath Reddy Sadipiralla</span><br style=3D=
"color:rgb(34,34,34)"><span style=3D"color:rgb(34,34,34)">EDB:=C2=A0</span>=
<a href=3D"https://www.enterprisedb.com/" style=3D"color:rgb(17,85,204)" ta=
rget=3D"_blank">https://www.enterprisedb.com/</a></div></div></div>

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