From 43b0f718af0776588844effb2b71d353b219483b Mon Sep 17 00:00:00 2001
From: Fujii Masao <fujii@postgresql.org>
Date: Fri, 16 Oct 2026 22:42:40 +0900
Subject: [PATCH] doc: Correct the description of server behavior after an OOM
 kill

The documentation stated that existing connections would continue to
function normally after the OOM killer terminated the postmaster.
In fact, those connections eventually terminate when server processes
detect the postmaster's death.

Clarify that the OOM killer can terminate either the postmaster or a
child process. If the postmaster is killed, the server must be restarted.
If a child process is killed, PostgreSQL typically terminates the
remaining connections and either recovers automatically or shuts down,
depending on restart_after_crash.

Backpatch to all supported versions.

Author: Takeshi Ideriha <iderihatakeshi@gmail.com>
Reviewed-by: Manuel Reyes Bravo <manuelreyesbravo@gmail.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/ce269321-a7f4-48f4-a9ca-a4a4983b9fd6@gmail.com
Backpatch-through: 14
---
 doc/src/sgml/runtime.sgml | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index bbda0eee621..39ac430987d 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1340,10 +1340,10 @@ default:\
     The default virtual memory behavior on Linux is not
     optimal for <productname>PostgreSQL</productname>. Because of the
     way that the kernel implements memory overcommit, the kernel might
-    terminate the <productname>PostgreSQL</productname> postmaster (the
-    supervisor server process) if the memory demands of either
-    <productname>PostgreSQL</productname> or another process cause the
-    system to run out of virtual memory.
+    terminate a <productname>PostgreSQL</productname> server process,
+    including the postmaster (the supervisor server process), if the memory
+    demands of either <productname>PostgreSQL</productname> or another process
+    cause the system to run out of virtual memory.
    </para>
 
    <para>
@@ -1355,9 +1355,15 @@ Out of Memory: Killed process 12345 (postgres).
 </programlisting>
     This indicates that the <filename>postgres</filename> process
     has been terminated due to memory pressure.
-    Although existing database connections will continue to function
-    normally, no new connections will be accepted.  To recover,
-    <productname>PostgreSQL</productname> will need to be restarted.
+    If the postmaster is terminated, all connections will eventually be
+    terminated.  To recover, <productname>PostgreSQL</productname> will
+    need to be restarted.
+    If a child process is terminated, <productname>PostgreSQL</productname> will
+    typically terminate all remaining connections and either recover
+    automatically, if
+    <link linkend="guc-restart-after-crash"><varname>restart_after_crash</varname></link>
+    is enabled, or shut down. If <productname>PostgreSQL</productname> shuts
+    down, it will need to be restarted to recover.
    </para>
 
    <para>