From 4b7bba49e71266ec378e672a1aaa9f16823449c2 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Tue, 29 Oct 2024 15:35:01 +0900 Subject: doc: Add better description for rewrite functions in event triggers There are two functions that can be used in event triggers to get more details about a rewrite happening on a relation. Both had a limited documentation: - pg_event_trigger_table_rewrite_reason() and pg_event_trigger_table_rewrite_oid() were not mentioned in the main event trigger section in the paragraph dedicated to the event table_rewrite. - pg_event_trigger_table_rewrite_reason() returns an integer which is a bitmap of the reasons why a rewrite happens. There was no explanation about the meaning of these values, forcing the reader to look at the code to find out that these are defined in event_trigger.h. While on it, let's add a comment in event_trigger.h where the AT_REWRITE_* are defined, telling to update the documentation when these values are changed. Backpatch down to 13 as a consequence of 1ad23335f36b, where this area of the documentation has been heavily reworked. Author: Greg Sabino Mullane Discussion: https://postgr.es/m/CAKAnmmL+Z6j-C8dAx1tVrnBmZJu+BSoc68WSg3sR+CVNjBCqbw@mail.gmail.com Backpatch-through: 13 --- doc/src/sgml/event-trigger.sgml | 5 +++++ doc/src/sgml/func.sgml | 8 ++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) (limited to 'doc/src') diff --git a/doc/src/sgml/event-trigger.sgml b/doc/src/sgml/event-trigger.sgml index d0306390346..cfa7b3d1b2d 100644 --- a/doc/src/sgml/event-trigger.sgml +++ b/doc/src/sgml/event-trigger.sgml @@ -104,6 +104,11 @@ control statements are available to rewrite a table, like CLUSTER and VACUUM, the table_rewrite event is not triggered by them. + To find the OID of the table that was rewritten, use the function + pg_event_trigger_table_rewrite_oid() (see + ). To discover the reason(s) + for the rewrite, use the function + pg_event_trigger_table_rewrite_reason(). diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 7be0324ac87..05f630c6a6c 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -31687,8 +31687,12 @@ CREATE EVENT TRIGGER test_event_trigger_for_drops integer - Returns a code explaining the reason(s) for rewriting. The exact - meaning of the codes is release dependent. + Returns a code explaining the reason(s) for rewriting. The value is + a bitmap built from the following values: 1 + (the table has changed its persistence), 2 + (default value of a column has changed), 4 + (a column has a new data type) and 8 + (the table access method has changed). -- cgit v1.2.3