From bb812ab0917e153f11bf449d7cb996815c07e387 Mon Sep 17 00:00:00 2001
From: Michael Paquier
Date: Wed, 24 Jan 2024 14:20:01 +0900
Subject: Fix ALTER TABLE .. ADD COLUMN with complex inheritance trees

This command, when used to add a column on a parent table with a complex
inheritance tree, tried to update multiple times the same tuple in
pg_attribute for a child table when incrementing attinhcount, causing
failures with "tuple already updated by self" because of a missing
CommandCounterIncrement() between two updates.

This exists for a rather long time, so backpatch all the way down.

Reported-by: Alexander Lakhin
Author: Tender Wang
Reviewed-by: Richard Guo
Discussion: https://postgr.es/m/18297-b04cd83a55b51e35@postgresql.org
Backpatch-through: 12
---
 src/backend/commands/tablecmds.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src/backend/commands')

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 2a56a4357c9..5ccd0eec1c7 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -7077,6 +7077,10 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 							colDef->colname, RelationGetRelationName(rel))));
 
 			table_close(attrdesc, RowExclusiveLock);
+
+			/* Make the child column change visible */
+			CommandCounterIncrement();
+
 			return InvalidObjectAddress;
 		}
 	}
-- 
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