From 420f9ac1b77cca142d4ab7919a4f2b703c1278b8 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 22 Dec 2021 16:38:38 +0900 Subject: [PATCH] Correct comment and some documentation about REPLICA_IDENTITY_INDEX catalog/pg_class.h was stating that REPLICA_IDENTITY_INDEX with a dropped index is equivalent to REPLICA_IDENTITY_DEFAULT. The code tells a different story, as it is equivalent to REPLICA_IDENTITY_NOTHING. The behavior exists since the introduction of replica identities, and fe7fd4e even added tests for this case but I somewhat forgot to fix this comment. While on it, this commit reorganizes the documentation about replica identities on the ALTER TABLE page, and a note is added about the case of dropped indexes with REPLICA_IDENTITY_INDEX. Author: Michael Paquier, Wei Wang Reviewed-by: Euler Taveira Discussion: https://postgr.es/m/OS3PR01MB6275464AD0A681A0793F56879E759@OS3PR01MB6275.jpnprd01.prod.outlook.com Backpatch-through: 10 --- doc/src/sgml/ref/alter_table.sgml | 51 ++++++++++++++++++++++++++----- src/include/catalog/pg_class.h | 2 +- 2 files changed, 44 insertions(+), 9 deletions(-) diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml index 18e09ee538..d4f2a73fc4 100644 --- a/doc/src/sgml/ref/alter_table.sgml +++ b/doc/src/sgml/ref/alter_table.sgml @@ -851,16 +851,51 @@ WITH ( MODULUS numeric_literal, REM This form changes the information which is written to the write-ahead log to identify rows which are updated or deleted. This option has no effect - except when logical replication is in use. DEFAULT - (the default for non-system tables) records the - old values of the columns of the primary key, if any. USING INDEX - records the old values of the columns covered by the named index, which - must be unique, not partial, not deferrable, and include only columns marked - NOT NULL. FULL records the old values of all columns - in the row. NOTHING records no information about the old row. - (This is the default for system tables.) + except when logical replication is in use. In all cases, no old values are logged unless at least one of the columns that would be logged differs between the old and new versions of the row. + + + DEFAULT + + + Records the old values of the columns of the primary key, if any. + This is the default for non-system tables. + + + + + + USING INDEX index_name + + + Records the old values of the columns covered by the named index, + that must be unique, not partial, not deferrable, and include only + columns marked NOT NULL. If this index is + dropped, the behavior is the same as NOTHING. + + + + + + FULL + + + Records the old values of all columns in the row. + + + + + + NOTHING + + + Records no information about the old row. This is the default for + system tables. + + + + diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h index 3e37729436..97e329e42a 100644 --- a/src/include/catalog/pg_class.h +++ b/src/include/catalog/pg_class.h @@ -185,7 +185,7 @@ DECLARE_INDEX(pg_class_tblspc_relfilenode_index, 3455, on pg_class using btree(r /* * an explicitly chosen candidate key's columns are used as replica identity. * Note this will still be set if the index has been dropped; in that case it - * has the same meaning as 'd'. + * has the same meaning as 'n'. */ #define REPLICA_IDENTITY_INDEX 'i'