Greetings, * Elizabeth Christensen (elizabeth.christen...@crunchydata.com) wrote: > > On Feb 26, 2024, at 4:21 PM, Stephen Frost <sfr...@snowman.net> wrote: > > * Elizabeth Christensen (elizabeth.christen...@crunchydata.com) wrote: > >> I have a small documentation patch to the HOT updates page > >> <https://www.postgresql.org/docs/current/storage-hot.html>to add references > >> to summary (BRIN) indexes not blocking HOT updates > >> <https://www.postgresql.org/message-id/cafp7qwpmrgcdaqumn7onn9hjrj3u4x3zrxdgft0k5g2jwvn...@mail.gmail.com>, > >> committed 19d8e2308b. > > > > Sounds good to me, though the attached patch didn't want to apply, and > > it isn't immediately clear to me why, but perhaps you could try saving > > the patch from a different editor and re-sending it? > > Thanks Stephen, attempt #2 here.
Here's an updated patch which tries to improve on the wording a bit by having it be a bit more consistent. Would certainly welcome feedback on it though, of course. This is a tricky bit of language to write and a complex optimization to explain. Thanks! Stephen
From bb88237d1f807572a496ff2a267ab56bef61ac8e Mon Sep 17 00:00:00 2001 From: Stephen Frost <sfr...@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 Backpatch-through: 16 Discussion: https://postgr.es/m/CABoUFXRjisr58Ct_3VsFEdQx+fJeQTWTdJnM7XAp=8mubto...@mail.gmail.com --- doc/src/sgml/storage.sgml | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml index 3ea4e5526d..d6c53a8d25 100644 --- a/doc/src/sgml/storage.sgml +++ b/doc/src/sgml/storage.sgml @@ -1097,8 +1097,11 @@ 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 (such + as <acronym>BRIN</acronym>) and does not update any columns + referenced by the table's non-summarizing indexes, including + expression and partial non-summarizing indexes. </para> </listitem> <listitem> @@ -1114,7 +1117,8 @@ 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 +1134,10 @@ 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
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