v1-0000-drop-constraint-for-hash-partition.patch

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index f798794556..ced4f9a658 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -643,7 +643,7 @@ static void QueuePartitionConstraintValidation(List **wqueue, Relation scanrel,
 											   List *partConstraint,
 											   bool validate_default);
 static void CloneRowTriggersToPartition(Relation parent, Relation partition);
-static void DetachAddConstraintIfNeeded(List **wqueue, Relation partRel);
+static ObjectAddress DetachAddConstraintIfNeeded(List **wqueue, Relation partRel);
 static void DropClonedTriggersFromPartition(Oid partitionId);
 static ObjectAddress ATExecDetachPartition(List **wqueue, AlteredTableInfo *tab,
 										   Relation rel, RangeVar *name,
@@ -19579,12 +19579,14 @@ ATExecDetachPartition(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		LOCKTAG		tag;
 		char	   *parentrelname;
 		char	   *partrelname;
+		ObjectAddress consAddress = InvalidObjectAddress;
+		PartitionDesc desc;
 
 		/*
 		 * Add a new constraint to the partition being detached, which
 		 * supplants the partition constraint (unless there is one already).
 		 */
-		DetachAddConstraintIfNeeded(wqueue, partRel);
+		consAddress = DetachAddConstraintIfNeeded(wqueue, partRel);
 
 		/*
 		 * We're almost done now; the only traces that remain are the
@@ -19653,6 +19655,32 @@ ATExecDetachPartition(List **wqueue, AlteredTableInfo *tab, Relation rel,
 					 errmsg("partition \"%s\" was removed concurrently", partrelname)));
 
 		tab->rel = rel;
+
+		/*
+		 * The hash partition's relpartbounds contains the oid of the parent
+		 * partition. If the parent partition is gone, a error is thrown when
+		 * checking constraints.
+		 */
+		desc = RelationGetPartitionDesc(rel, true);
+		if (desc && desc->boundinfo->strategy == PARTITION_STRATEGY_HASH &&
+			OidIsValid(consAddress.objectId))
+		{
+			Relation	constraintRelation;
+			HeapTuple	constraintTuple;
+			Form_pg_constraint con;
+
+			constraintRelation = table_open(ConstraintRelationId, RowExclusiveLock);
+			constraintTuple = SearchSysCacheCopy1(CONSTROID, ObjectIdGetDatum(consAddress.objectId));
+			if (!HeapTupleIsValid(constraintTuple))
+				elog(ERROR, "cache lookup failed for constraint %u", consAddress.objectId);
+			con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
+
+			ATExecDropConstraint(partRel, con->conname.data, DROP_CASCADE, true,
+								 true, ShareUpdateExclusiveLock);
+
+			heap_freetuple(constraintTuple);
+			table_close(constraintRelation, RowExclusiveLock);
+		}
 	}
 
 	/* Do the final part of detaching */
@@ -19946,10 +19974,11 @@ ATExecDetachPartitionFinalize(Relation rel, RangeVar *name)
  *		a dupe if an constraint already exists which implies the needed
  *		constraint.
  */
-static void
+static ObjectAddress
 DetachAddConstraintIfNeeded(List **wqueue, Relation partRel)
 {
 	List	   *constraintExpr;
+	ObjectAddress address = InvalidObjectAddress;
 
 	constraintExpr = RelationGetPartitionQual(partRel);
 	constraintExpr = (List *) eval_const_expressions(NULL, (Node *) constraintExpr);
@@ -19976,9 +20005,12 @@ DetachAddConstraintIfNeeded(List **wqueue, Relation partRel)
 		n->initially_valid = true;
 		n->skip_validation = true;
 		/* It's a re-add, since it nominally already exists */
-		ATAddCheckNNConstraint(wqueue, tab, partRel, n,
-							   true, false, true, ShareUpdateExclusiveLock);
+		address = ATAddCheckNNConstraint(wqueue, tab, partRel, n,
+										 true, false, true,
+										 ShareUpdateExclusiveLock);
 	}
+
+	return address;
 }
 
 /*
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 7666c76238..af0d3c06a6 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -4359,6 +4359,23 @@ Check constraints:
     "part_rp100_a_check" CHECK (a >= 123 AND a < 133 AND a IS NOT NULL)
 
 DROP TABLE range_parted2;
+CREATE TABLE hash_parted2 (
+	a int,
+	b int
+) PARTITION BY HASH (a part_test_int4_ops);
+CREATE TABLE hpart2_1 PARTITION OF hash_parted2 FOR VALUES WITH (MODULUS 4, REMAINDER 0);
+ALTER TABLE hash_parted2 DETACH PARTITION hpart2_1 CONCURRENTLY;
+DROP TABLE hash_parted2;
+-- constraint should not be created
+\d hpart2_1
+              Table "public.hpart2_1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+
+INSERT INTO hpart2_1 SELECT 1;
+DROP TABLE hpart2_1;
 -- Check ALTER TABLE commands for partitioned tables and partitions
 -- cannot add/drop column to/from *only* the parent
 ALTER TABLE ONLY list_parted2 ADD COLUMN c int;
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 9df5a63bdf..55f2635ab9 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -2786,6 +2786,18 @@ ALTER TABLE range_parted2 DETACH PARTITION part_rp100 CONCURRENTLY;
 \d part_rp100
 DROP TABLE range_parted2;
 
+CREATE TABLE hash_parted2 (
+	a int,
+	b int
+) PARTITION BY HASH (a part_test_int4_ops);
+CREATE TABLE hpart2_1 PARTITION OF hash_parted2 FOR VALUES WITH (MODULUS 4, REMAINDER 0);
+ALTER TABLE hash_parted2 DETACH PARTITION hpart2_1 CONCURRENTLY;
+DROP TABLE hash_parted2;
+-- constraint should not be created
+\d hpart2_1
+INSERT INTO hpart2_1 SELECT 1;
+DROP TABLE hpart2_1;
+
 -- Check ALTER TABLE commands for partitioned tables and partitions
 
 -- cannot add/drop column to/from *only* the parent