fix concurrent issue in ALTER DOMAIN

we should ensure that two backends can not ALTER DOMAIN at the same time

discussion: https://postgr.es/m/

Author: jianhe-fun

src/backend/commands/typecmds.c

@@ -2631,6 +2631,13 @@ AlterDomainDefault(List *names, Node *defaultRaw)
 	typename = makeTypeNameFromNameList(names);
 	domainoid = typenameTypeId(NULL, typename);
 
+	/*
+	 * Acquire a lock on the domain type, which we won't release until commit.
+	 * This ensures that two backends aren't concurrently modifying the same
+	 * domain type.
+	 */
+	LockDatabaseObject(TypeRelationId, domainoid, 0, AccessExclusiveLock);
+
 	/* Look up the domain in the type table */
 	rel = table_open(TypeRelationId, RowExclusiveLock);
 
@@ -2753,6 +2760,13 @@ AlterDomainNotNull(List *names, bool notNull)
 	typename = makeTypeNameFromNameList(names);
 	domainoid = typenameTypeId(NULL, typename);
 
+	/*
+	 * Acquire a lock on the domain type, which we won't release until commit.
+	 * This ensures that two backends aren't concurrently modifying the same
+	 * domain type.
+	 */
+	LockDatabaseObject(TypeRelationId, domainoid, 0, AccessExclusiveLock);
+
 	/* Look up the domain in the type table */
 	typrel = table_open(TypeRelationId, RowExclusiveLock);
 
@@ -2844,6 +2858,13 @@ AlterDomainDropConstraint(List *names, const char *constrName,
 	typename = makeTypeNameFromNameList(names);
 	domainoid = typenameTypeId(NULL, typename);
 
+	/*
+	 * Acquire a lock on the domain type, which we won't release until commit.
+	 * This ensures that two backends aren't concurrently modifying the same
+	 * domain type.
+	 */
+	LockDatabaseObject(TypeRelationId, domainoid, 0, AccessExclusiveLock);
+
 	/* Look up the domain in the type table */
 	rel = table_open(TypeRelationId, RowExclusiveLock);
 
@@ -2948,6 +2969,13 @@ AlterDomainAddConstraint(List *names, Node *newConstraint,
 	typename = makeTypeNameFromNameList(names);
 	domainoid = typenameTypeId(NULL, typename);
 
+	/*
+	 * Acquire a lock on the domain type, which we won't release until commit.
+	 * This ensures that two backends aren't concurrently modifying the same
+	 * domain type.
+	 */
+	LockDatabaseObject(TypeRelationId, domainoid, 0, AccessExclusiveLock);
+
 	/* Look up the domain in the type table */
 	typrel = table_open(TypeRelationId, RowExclusiveLock);
 
@@ -3050,6 +3078,13 @@ AlterDomainValidateConstraint(List *names, const char *constrName)
 	typename = makeTypeNameFromNameList(names);
 	domainoid = typenameTypeId(NULL, typename);
 
+	/*
+	 * Acquire a lock on the domain type, which we won't release until commit.
+	 * This ensures that two backends aren't concurrently modifying the same
+	 * domain type.
+	 */
+	LockDatabaseObject(TypeRelationId, domainoid, 0, AccessExclusiveLock);
+
 	/* Look up the domain in the type table */
 	typrel = table_open(TypeRelationId, AccessShareLock);
 

src/test/isolation/expected/domains.out

@@ -0,0 +1,58 @@
+Parsed test spec with 2 sessions
+
+starting permutation: b1 b2 s_add s2_drop c1 c2
+step b1: BEGIN;
+step b2: BEGIN;
+step s_add: ALTER DOMAIN dd ADD CONSTRAINT dd_check1 CHECK(VALUE > 0);
+step s2_drop: DROP DOMAIN dd; <waiting ...>
+step c1: COMMIT;
+step s2_drop: <... completed>
+step c2: COMMIT;
+
+starting permutation: b1 b2 s_add s2_set c1 c2
+step b1: BEGIN;
+step b2: BEGIN;
+step s_add: ALTER DOMAIN dd ADD CONSTRAINT dd_check1 CHECK(VALUE > 0);
+step s2_set: ALTER DOMAIN dd SET DEFAULT 3; <waiting ...>
+step c1: COMMIT;
+step s2_set: <... completed>
+step c2: COMMIT;
+
+starting permutation: b1 b2 s1_set s1_drop s2_set c1 c2
+step b1: BEGIN;
+step b2: BEGIN;
+step s1_set: ALTER DOMAIN dd SET NOT NULL;
+step s1_drop: ALTER DOMAIN dd DROP DEFAULT;
+step s2_set: ALTER DOMAIN dd SET DEFAULT 3; <waiting ...>
+step c1: COMMIT;
+step s2_set: <... completed>
+step c2: COMMIT;
+
+starting permutation: b1 b2 s1_drop s2_set c1 c2
+step b1: BEGIN;
+step b2: BEGIN;
+step s1_drop: ALTER DOMAIN dd DROP DEFAULT;
+step s2_set: ALTER DOMAIN dd SET DEFAULT 3; <waiting ...>
+step c1: COMMIT;
+step s2_set: <... completed>
+step c2: COMMIT;
+
+starting permutation: b1 b2 s1_set s1_drop2 v2 c1 c2
+step b1: BEGIN;
+step b2: BEGIN;
+step s1_set: ALTER DOMAIN dd SET NOT NULL;
+step s1_drop2: ALTER DOMAIN dd DROP CONSTRAINT cc;
+step v2: ALTER DOMAIN dd VALIDATE CONSTRAINT cc; <waiting ...>
+step c1: COMMIT;
+step v2: <... completed>
+ERROR:  constraint "cc" of domain "dd" does not exist
+step c2: COMMIT;
+
+starting permutation: b1 b2 v2 s1_drop2 c2 c1
+step b1: BEGIN;
+step b2: BEGIN;
+step v2: ALTER DOMAIN dd VALIDATE CONSTRAINT cc;
+step s1_drop2: ALTER DOMAIN dd DROP CONSTRAINT cc; <waiting ...>
+step c2: COMMIT;
+step s1_drop2: <... completed>
+step c1: COMMIT;

src/test/isolation/isolation_schedule

@@ -118,3 +118,4 @@ test: serializable-parallel-2
 test: serializable-parallel-3
 test: matview-write-skew
 test: lock-nowait
+test: domains

src/test/isolation/specs/domains.spec

@@ -0,0 +1,32 @@
+setup
+{
+    CREATE DOMAIN dd AS INT;
+    ALTER DOMAIN dd ADD CONSTRAINT cc CHECK(VALUE > 1) NOT VALID;
+}
+
+teardown
+{
+    DROP DOMAIN IF EXISTS dd CASCADE;
+}
+
+session s1
+step b1         { BEGIN; }
+step s_add      { ALTER DOMAIN dd ADD CONSTRAINT dd_check1 CHECK(VALUE > 0); }
+step s1_drop    { ALTER DOMAIN dd DROP DEFAULT; }
+step s1_set     { ALTER DOMAIN dd SET NOT NULL; }
+step s1_drop2   { ALTER DOMAIN dd DROP CONSTRAINT cc;}
+step c1         { COMMIT; }
+
+session s2
+step b2         { BEGIN; }
+step s2_set     { ALTER DOMAIN dd SET DEFAULT 3; }
+step s2_drop    { DROP DOMAIN dd; }
+step v2         { ALTER DOMAIN dd VALIDATE CONSTRAINT cc; }
+step c2         { COMMIT; }
+
+permutation b1 b2 s_add s2_drop c1 c2
+permutation b1 b2 s_add s2_set c1 c2
+permutation b1 b2 s1_set s1_drop s2_set c1 c2
+permutation b1 b2 s1_drop s2_set c1 c2
+permutation b1 b2 s1_set s1_drop2 v2 c1 c2
+permutation b1 b2 v2 s1_drop2  c2 c1