postgres.git / summary / log / commit / refs

commit    7f77f2aec3d06e580915acf16c4d7c7c5d998f23
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Thu Aug 15 15:14:26 2019 +0000
First released in: 13.0, 9.4.25, 9.5.20, 9.6.16, 10.11, 11.6, 12.0

    Doc: improve documentation about postgresql.auto.conf.
    
    Clarify what external tools can do to this file, and add a bit
    of detail about what ALTER SYSTEM itself does.
    
    Discussion: https://postgr.es/m/aed6cc9f-98f3-2693-ac81-52bb0052307e@2ndquadrant.com


 doc/src/sgml/config.sgml | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 86a17cb6a48..6cf59c9bed4 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -137,6 +137,8 @@ shared_buffers = 128MB
      identifiers or numbers must be single-quoted.  To embed a single
      quote in a parameter value, write either two quotes (preferred)
      or backslash-quote.
+     If the file contains multiple entries for the same parameter,
+     all but the last one are ignored.
     </para>
 
     <para>
@@ -169,18 +171,29 @@ shared_buffers = 128MB
      In addition to <filename>postgresql.conf</filename>,
      a <productname>PostgreSQL</productname> data directory contains a file
      <filename>postgresql.auto.conf</filename><indexterm><primary>postgresql.auto.conf</primary></indexterm>,
-     which has the same format as <filename>postgresql.conf</filename> but should
-     never be edited manually.  This file holds settings provided through
-     the <xref linkend="sql-altersystem"/> command.  This file is automatically
-     read whenever <filename>postgresql.conf</filename> is, and its settings take
-     effect in the same way.  Settings in <filename>postgresql.auto.conf</filename>
-     override those in <filename>postgresql.conf</filename>.
+     which has the same format as <filename>postgresql.conf</filename> but
+     is intended to be edited automatically not manually.  This file holds
+     settings provided through the <xref linkend="sql-altersystem"/> command.
+     This file is read whenever <filename>postgresql.conf</filename> is,
+     and its settings take effect in the same way.  Settings
+     in <filename>postgresql.auto.conf</filename> override those
+     in <filename>postgresql.conf</filename>.
+    </para>
+
+    <para>
+     External tools may also
+     modify <filename>postgresql.auto.conf</filename>.  It is not
+     recommended to do this while the server is running, since a
+     concurrent <command>ALTER SYSTEM</command> command could overwrite
+     such changes.  Such tools might simply append new settings to the end,
+     or they might choose to remove duplicate settings and/or comments
+     (as <command>ALTER SYSTEM</command> will).
     </para>
 
     <para>
      The system view
      <link linkend="view-pg-file-settings"><structname>pg_file_settings</structname></link>
-     can be helpful for pre-testing changes to the configuration file, or for
+     can be helpful for pre-testing changes to the configuration files, or for
      diagnosing problems if a <systemitem>SIGHUP</systemitem> signal did not have the
      desired effects.
     </para>


[parent: 32d38f54a369]