From 252b707bc41cc9bf6c55c18d8cb302a6176b7e48 Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Wed, 17 Apr 2019 13:51:48 +0200
Subject: Return NULL for checksum failures if checksums are not enabled

Returning 0 could falsely indicate that there is no problem. NULL
correctly indicates that there is no information about potential
problems.

Also return 0 as numbackends instead of NULL for shared objects (as no
connection can be made to a shared object only).

Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
---
 doc/src/sgml/monitoring.sgml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 547fe4cce93..a179d6111e4 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -2600,13 +2600,15 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
      <entry><structfield>checksum_failures</structfield></entry>
      <entry><type>bigint</type></entry>
      <entry>Number of data page checksum failures detected in this
-     database</entry>
+      database (or on a shared object), or NULL if data checksums are not
+      enabled.</entry>
     </row>
     <row>
      <entry><structfield>checksum_last_failure</structfield></entry>
      <entry><type>timestamp with time zone</type></entry>
      <entry>Time at which the last data page checksum failure was detected in
-     this database, or on a shared object.</entry>
+      this database (or on a shared object), or NULL if data checksums are not
+      enabled.</entry>
     </row>
     <row>
      <entry><structfield>blk_read_time</structfield></entry>
-- 
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