diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index ad28225b36..25c605bfc5 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -404,7 +404,9 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 /*
  * AlterSequence
  *
- * Modify the definition of a sequence relation
+ * Modify the definition of a sequence relation. The operation is not
+ * transactional and uses a minimal locking to not disrupt parallel
+ * sessions working with this sequence.
  */
 ObjectAddress
 AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
@@ -439,7 +441,11 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 					   stmt->sequence->relname);
 
-	/* lock page' buffer and read tuple into new sequence structure */
+	/*
+	 * Lock page buffer and read tuple into new sequence structure.
+	 * The lock is hold for the duration of the tuple update in the
+	 * catalog.
+	 */
 	seqdata = read_seq_tuple(seqrel, &buf, &seqdatatuple);
 
 	/* Copy old values of options into workspace */
@@ -494,8 +500,6 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
-
 	/* process OWNED BY if given */
 	if (owned_by)
 		process_owned_by(seqrel, owned_by, stmt->for_identity);
@@ -506,9 +510,12 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 
 	relation_close(seqrel, NoLock);
 
-	CatalogTupleUpdate(rel, &tuple->t_self, tuple);
+	heap_inplace_update(rel, tuple);
+
 	heap_close(rel, RowExclusiveLock);
 
+	UnlockReleaseBuffer(buf);
+
 	return address;
 }
 
diff --git a/src/test/isolation/expected/alter-sequence.out b/src/test/isolation/expected/alter-sequence.out
new file mode 100644
index 0000000000..d0937f0f48
--- /dev/null
+++ b/src/test/isolation/expected/alter-sequence.out
@@ -0,0 +1,14 @@
+Parsed test spec with 2 sessions
+
+starting permutation: b1 as1 as2 c1
+step b1: BEGIN;
+step as1: ALTER SEQUENCE myseq MAXVALUE 10;
+step as2: ALTER SEQUENCE myseq RESTART 1;
+step c1: COMMIT;
+
+starting permutation: b1 as1 q2 c1
+step b1: BEGIN;
+step as1: ALTER SEQUENCE myseq MAXVALUE 10;
+step q2: SELECT nextval('myseq') FROM generate_series(1, 12);
+ERROR:  nextval: reached maximum value of sequence "myseq" (10)
+step c1: COMMIT;
diff --git a/src/test/isolation/specs/alter-sequence.spec b/src/test/isolation/specs/alter-sequence.spec
new file mode 100644
index 0000000000..b9a4ce601f
--- /dev/null
+++ b/src/test/isolation/specs/alter-sequence.spec
@@ -0,0 +1,25 @@
+# ALTER SEQUENCE - Set and use of values
+
+setup
+{
+ CREATE SEQUENCE myseq;
+}
+
+teardown
+{
+ DROP SEQUENCE myseq;
+}
+
+session "s1"
+step "b1"	{ BEGIN; }
+step "as1"	{ ALTER SEQUENCE myseq MAXVALUE 10; }
+step "c1"	{ COMMIT; }
+
+session "s2"
+step "as2"	{ ALTER SEQUENCE myseq RESTART 1; }
+step "q2"   { SELECT nextval('myseq') FROM generate_series(1, 12); }
+
+# No concurrency errors
+permutation "b1" "as1" "as2" "c1"
+# nextval() call will fail because of MAXVALUE changed
+permutation "b1" "as1" "q2" "c1"