v4-0001-Adding-Summary-Index-Info-to-HOT-Update-Documentatio.patch

From 131f83868b947b379e57ea3dad0acf5a4f95bca8 Mon Sep 17 00:00:00 2001
From: Stephen Frost <sfrost@snowman.net>
Date: Mon, 26 Feb 2024 17:17:54 -0500
Subject: [PATCH] docs: Update HOT update docs for 19d8e2308b

Commit 19d8e2308b changed when the HOT update optimization is possible
but neglected to update the Heap-Only Tuples (HOT) documentation.  This
patch updates that documentation accordingly.

Author: Elizabeth Christensen
Reviewed-By: Stephen Frost, Alvaro Herrera
Backpatch-through: 16
Discussion: https://postgr.es/m/CABoUFXRjisr58Ct_3VsFEdQx+fJeQTWTdJnM7XAp=8MUbtoa9A@mail.gmail.com
---
 doc/src/sgml/storage.sgml | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 3ea4e5526d..f2bb0283ae 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -1097,8 +1097,13 @@ data. Empty in ordinary tables.</entry>
   <itemizedlist>
    <listitem>
     <para>
-     The update does not modify any columns referenced by the table's
-     indexes, including expression and partial indexes.
+     The update only modifies columns which are not referenced by the
+     table's indexes or are only referenced by summarizing indexes and
+     does not update any columns referenced by the table's
+     non-summarizing indexes, including expression and partial
+     non-summarizing indexes.  The only summarizing index in the core
+     <productname>PostgreSQL</productname> distribution is
+     <acronym>BRIN</acronym>.
      </para>
    </listitem>
    <listitem>
@@ -1114,7 +1119,8 @@ data. Empty in ordinary tables.</entry>
   <itemizedlist>
    <listitem>
     <para>
-     New index entries are not needed to represent updated rows.
+     New index entries are not needed to represent updated rows, however,
+     summary indexes may still need to be updated.
     </para>
    </listitem>
    <listitem>
@@ -1130,11 +1136,10 @@ data. Empty in ordinary tables.</entry>
  </para>
 
  <para>
-  In summary, heap-only tuple updates can only be created
-  if columns used by indexes are not updated.  You can
-  increase the likelihood of sufficient page space for
-  <acronym>HOT</acronym> updates by decreasing a table's <link
-  linkend="reloption-fillfactor"><literal>fillfactor</literal></link>.
+  In summary, heap-only tuple updates can only be created if columns used by
+  non-summarizing indexes are not updated. You can increase the likelihood of
+  sufficient page space for <acronym>HOT</acronym> updates by decreasing
+  a table's <link linkend="reloption-fillfactor"><literal>fillfactor</literal></link>.
   If you don't, <acronym>HOT</acronym> updates will still happen because
   new rows will naturally migrate to new pages and existing pages with
   sufficient free space for new row versions.  The system view <link
-- 
2.34.1