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From: VASUKI M <vasukim1992002@gmail.com>
Date: Tue, 4 Nov 2025 10:53:56 +0530
Message-ID: 
 <CACTYHzhv1K1Jpe+bT0z1Oxod3d0odYW8yLuB_9q5NFyUHY6=zA@mail.gmail.com>
Subject: Autofail back inconsistent
To: ishii@postgresql.org, Bo Peng <pengbo@sraoss.co.jp>
Cc: pgpool-hackers@lists.postgresql.org, bharatdb@cdac.in
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Hi Pgpool-II Community,

I=E2=80=99ve been working with PostgreSQL for quite some time, and while ma=
naging
backend servers with Pgpool-II, I noticed that there=E2=80=99s no built-in =
data
synchronization before standby nodes are reattached.

To address this, I=E2=80=99ve developed a new enhancement for Pgpool-II cal=
led
*=E2=80=9CAutomatic
Resync and Reattach=E2=80=9D*, aimed at improving high availability and red=
ucing
manual intervention after node failures.

This feature automatically performs:

   -

   *pg_rewind synchronization* and *WAL replay* for failed or lagging
   standby nodes
   -

   *Automatic reattachment* of standby nodes once they are safely resynced

This enhancement overcomes some limitations of existing features:

   -

   *Online Recovery* =E2=80=93 requires manual execution of pcp_recovery_no=
de
   -

   *Auto Failback* =E2=80=93 may reattach inconsistent nodes without synchr=
onization

With *Auto Resync & Reattach*, Pgpool-II ensures data safety and
consistency during failover recovery, providing a more robust and
self-healing HA environment.

I=E2=80=99ve created a dedicated GitHub repository with setup instructions,
configuration samples, and architecture diagrams here:
 https://github.com/BharatDBPG/pgpool2-auto-resync

The repository includes:

   -

   Enhanced failover.sh and follow_primary.sh scripts (handling both
   primary and standby failures)
   -

   A new resync.sh script integrating pg_rewind + WAL replay
   -

   Sample configuration files for a *1 Primary + 2 Standby* setup

I would love to receive feedback or suggestions from the community
regarding possible improvements or integration ideas.

I will be happy to share a patch if needed.
Thank you for your time and support.

Best regards,

*Vasuki MCDAC,CHENNAI*

https://github.com/BharatDBPG/pgpool2-auto-resync

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<div dir=3D"ltr"><p>Hi Pgpool-II Community,</p><p>I=E2=80=99ve been working=
 with PostgreSQL for quite some time, and while managing backend servers wi=
th Pgpool-II, I noticed that there=E2=80=99s no built-in data synchronizati=
on before standby nodes are reattached.</p><p>To address this, I=E2=80=99ve=
 developed a new enhancement for Pgpool-II called <strong>=E2=80=9CAutomati=
c Resync and Reattach=E2=80=9D</strong>, aimed at improving high availabili=
ty and reducing manual intervention after node failures.</p><p>This feature=
 automatically performs:</p><ul>
<li>
<p><strong>pg_rewind synchronization</strong> and <strong>WAL replay</stron=
g> for failed or lagging standby nodes</p>
</li>
<li>
<p><strong>Automatic reattachment</strong> of standby nodes once they are s=
afely resynced</p>
</li>
</ul><p>This enhancement overcomes some limitations of existing features:</=
p><ul>
<li>
<p><strong>Online Recovery</strong> =E2=80=93 requires manual execution of =
<code>pcp_recovery_node</code></p>
</li>
<li>
<p><strong>Auto Failback</strong> =E2=80=93 may reattach inconsistent nodes=
 without synchronization</p>
</li>
</ul><p>With <strong>Auto Resync &amp; Reattach</strong>, Pgpool-II ensures=
 data safety and consistency during failover recovery, providing a more rob=
ust and self-healing HA environment.</p><p>


</p><p>I=E2=80=99ve created a dedicated GitHub repository with setup instru=
ctions, configuration samples, and architecture diagrams here:<br>=C2=A0<a =
class=3D"gmail-decorated-link" rel=3D"noopener" href=3D"https://github.com/=
BharatDBPG/pgpool2-auto-resync">https://github.com/BharatDBPG/pgpool2-auto-=
resync</a><br><br></p><p>The repository includes:</p><ul>
<li>
<p>Enhanced <code>failover.sh</code> and <code>follow_primary.sh</code> scr=
ipts (handling both primary and standby failures)</p>
</li>
<li>
<p>A new <code>resync.sh</code> script integrating <code>pg_rewind</code> +=
 WAL replay</p>
</li>
<li>
<p>Sample configuration files for a <strong>1 Primary + 2 Standby</strong> =
setup</p>
</li>
</ul><p>I would love to receive feedback or suggestions from the community =
regarding possible improvements or integration ideas.</p><p>I will be happy=
 to share a patch if needed.<br>Thank you for your time and support.</p><p>


</p><p>Best regards,<br>
<strong>Vasuki M<br>CDAC,CHENNAI</strong></p><p><a href=3D"https://github.c=
om/BharatDBPG/pgpool2-auto-resync">https://github.com/BharatDBPG/pgpool2-au=
to-resync</a><span aria-hidden=3D"true" class=3D"gmail-ms-0.5 gmail-inline-=
block gmail-align-middle gmail-leading-none"></span><strong></strong></p></=
div>

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