From fd31f9f033213e2ebf00b57ef837e1828c338fc4 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 17 Sep 2017 12:16:38 -0400
Subject: Ensure that BEFORE STATEMENT triggers fire the right number of times.

Commit 0f79440fb introduced mechanism to keep AFTER STATEMENT triggers
from firing more than once per statement, which was formerly possible
if more than one FK enforcement action had to be applied to a given
table.  Add a similar mechanism for BEFORE STATEMENT triggers, so that
we don't have the unexpected situation of firing BEFORE STATEMENT
triggers more often than AFTER STATEMENT.

As with the previous patch, back-patch to v10.

Discussion: https://postgr.es/m/22315.1505584992@sss.pgh.pa.us
---
 doc/src/sgml/ref/create_trigger.sgml | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 065c8272710..2496250bed8 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -250,7 +250,8 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="PARAMETER">name</replaceable>
       One of <literal>INSERT</literal>, <literal>UPDATE</literal>,
       <literal>DELETE</literal>, or <literal>TRUNCATE</literal>;
       this specifies the event that will fire the trigger. Multiple
-      events can be specified using <literal>OR</literal>.
+      events can be specified using <literal>OR</literal>, except when
+      transition relations are requested.
      </para>
 
      <para>
@@ -263,7 +264,10 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
       is mentioned as a target of the <command>UPDATE</> command.
      </para>
 
-     <para><literal>INSTEAD OF UPDATE</> events do not support lists of columns.
+     <para>
+      <literal>INSTEAD OF UPDATE</> events do not allow a list of columns.
+      A column list cannot be specified when requesting transition relations,
+      either.
      </para>
     </listitem>
    </varlistentry>
@@ -490,9 +494,9 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
    trigger that requests transition relations will cause the foreign-key
    enforcement actions triggered by a single SQL command to be split into
    multiple steps, each with its own transition relation(s).  In such cases,
-   any <literal>AFTER STATEMENT</> triggers that are present will be fired
-   once per creation of a transition relation, ensuring that the triggers see
-   each affected row once and only once.
+   any statement-level triggers that are present will be fired once per
+   creation of a transition relation set, ensuring that the triggers see
+   each affected row in a transition relation once and only once.
   </para>
 
   <para>
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