From ad385a494f6ad863b38aa7c708f23aaf223438a7 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 8 Apr 2022 11:02:59 -0400
Subject: [PATCH] docs: Note the recovery_min_apply_delay bloats pg_wal.
Those WAL files that we're waiting to apply have to be stored
somewhere.
Thom Brown
Discussion: http://postgr.es/m/CAA-aLv4SkJRK6GGcd0Axt8kt6_eWMEbtG7f8NJpFh+rNshtdNA@mail.gmail.com
---
doc/src/sgml/config.sgml | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 81cacdcbe40..cfbb20a39e1 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4872,6 +4872,12 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
state, until the standby is promoted or triggered. After that the standby
will end recovery without further waiting.
</para>
+ <para>
+ WAL records must be kept on the standby until they are ready to be
+ applied. Therefore, longer delays will result in a greater accumulation
+ of WAL files, increasing disk space requirements for the standby's
+ <filename>pg_wal</filename> directory.
+ </para>
<para>
This parameter is intended for use with streaming replication deployments;
however, if the parameter is specified it will be honored in all cases