Need to do CommandCounterIncrement after StoreAttrMissingVal.

tglsfdc · tglsfdc · commit d31d39cfe4f5 · 2025-04-02T11:13:01.000-04:00
Without this, an additional change to the same pg_attribute row within the same command will fail. This is possible at least with ALTER TABLE ADD COLUMN on a multiple-inheritance-pathway structure. (Another potential hazard is that immediately-following operations might not see the missingval.) Introduced by 95f6506, which split the former coding that used a single pg_attribute update to change both atthasdef and atthasmissing/attmissingval into two updates, but missed that this should entail two CommandCounterIncrements as well. Like that fix, back-patch through v13. Reported-by: Alexander Lakhin <exclusion@gmail.com> Author: Tender Wang <tndrwang@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/025a3ffa-5eff-4a88-97fb-8f583b015965@gmail.com Backpatch-through: 13
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
@@ -6950,6 +6950,8 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				if (!missingIsNull)
 				{
 					StoreAttrMissingVal(rel, attribute.attnum, missingval);
+					/* Make the additional catalog change visible */
+					CommandCounterIncrement();
 					has_missing = true;
 				}
 				FreeExecutorState(estate);
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
@@ -1093,17 +1093,30 @@ CREATE TABLE inhta ();
 CREATE TABLE inhtb () INHERITS (inhta);
 CREATE TABLE inhtc () INHERITS (inhtb);
 CREATE TABLE inhtd () INHERITS (inhta, inhtb, inhtc);
-ALTER TABLE inhta ADD COLUMN i int;
+ALTER TABLE inhta ADD COLUMN i int, ADD COLUMN j bigint DEFAULT 1;
 NOTICE:  merging definition of column "i" for child "inhtd"
 NOTICE:  merging definition of column "i" for child "inhtd"
+NOTICE:  merging definition of column "j" for child "inhtd"
+NOTICE:  merging definition of column "j" for child "inhtd"
 \d+ inhta
                                    Table "public.inhta"
  Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
 --------+---------+-----------+----------+---------+---------+--------------+-------------
  i      | integer |           |          |         | plain   |              | 
+ j      | bigint  |           |          | 1       | plain   |              | 
 Child tables: inhtb,
               inhtd
 
+\d+ inhtd
+                                   Table "public.inhtd"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ i      | integer |           |          |         | plain   |              | 
+ j      | bigint  |           |          | 1       | plain   |              | 
+Inherits: inhta,
+          inhtb,
+          inhtc
+
 DROP TABLE inhta, inhtb, inhtc, inhtd;
 -- Test for renaming in diamond inheritance
 CREATE TABLE inht2 (x int) INHERITS (inht1);
diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
@@ -377,8 +377,9 @@ CREATE TABLE inhta ();
 CREATE TABLE inhtb () INHERITS (inhta);
 CREATE TABLE inhtc () INHERITS (inhtb);
 CREATE TABLE inhtd () INHERITS (inhta, inhtb, inhtc);
-ALTER TABLE inhta ADD COLUMN i int;
+ALTER TABLE inhta ADD COLUMN i int, ADD COLUMN j bigint DEFAULT 1;
 \d+ inhta
+\d+ inhtd
 DROP TABLE inhta, inhtb, inhtc, inhtd;
 
 -- Test for renaming in diamond inheritance

Original file line number	Diff line number	Diff line change
`@@ -6950,6 +6950,8 @@ ATExecAddColumn(List *wqueue, AlteredTableInfo tab, Relation rel,`
`6950`	`6950`	`if (!missingIsNull)`
`6951`	`6951`	`{`
`6952`	`6952`	`StoreAttrMissingVal(rel, attribute.attnum, missingval);`
	`6953`	`+ /* Make the additional catalog change visible */`
	`6954`	`+ CommandCounterIncrement();`
`6953`	`6955`	`has_missing = true;`
`6954`	`6956`	`}`
`6955`	`6957`	`FreeExecutorState(estate);`