Make DDL operations play nicely with Serializable Snapshot Isolation.

Truncating or dropping a table is treated like deletion of all tuples, and
check for conflicts accordingly. If a table is clustered or rewritten by
ALTER TABLE, all predicate locks on the heap are promoted to relation-level
locks, because the tuple or page ids of any existing tuples will change and
won't be valid after rewriting the table. Arguably ALTER TABLE should be
treated like a mass-UPDATE of every row, but if you e.g change the datatype
of a column, you could also argue that it's just a change to the physical
layout, not a logical change. Reindexing promotes all locks on the index to
relation-level lock on the heap.

Kevin Grittner, with a lot of cosmetic changes by me.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index dc0f6059b04..0ab3a8bcfae 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -39,6 +39,7 @@
 #include "optimizer/planner.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
+#include "storage/predicate.h"
 #include "storage/procarray.h"
 #include "storage/smgr.h"
 #include "utils/acl.h"
@@ -385,6 +386,14 @@ cluster_rel(Oid tableOid, Oid indexOid, bool recheck, bool verbose,
 	if (OidIsValid(indexOid))
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+	/*
+	 * All predicate locks on the tuples or pages are about to be made
+	 * invalid, because we move tuples around.	Promote them to relation
+	 * locks.  Predicate locks on indexes will be promoted when they are
+	 * reindexed.
+	 */
+	TransferPredicateLocksToHeapRelation(OldHeap);
+
 	/* rebuild_relation does all the dirty work */
 	rebuild_relation(OldHeap, indexOid, freeze_min_age, freeze_table_age,
 					 verbose);