1 files changed, 30 insertions, 15 deletions

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index a546292da6e..a753b207008 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -836,7 +836,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 		erm->prti = rc->prti;
 		erm->rowmarkId = rc->rowmarkId;
 		erm->markType = rc->markType;
-		erm->noWait = rc->noWait;
+		erm->waitPolicy = rc->waitPolicy;
 		ItemPointerSetInvalid(&(erm->curCtid));
 		estate->es_rowMarks = lappend(estate->es_rowMarks, erm);
 	}
@@ -1871,7 +1871,7 @@ EvalPlanQual(EState *estate, EPQState *epqstate,
 	/*
 	 * Get and lock the updated version of the row; if fail, return NULL.
 	 */
-	copyTuple = EvalPlanQualFetch(estate, relation, lockmode, false /* wait */,
+	copyTuple = EvalPlanQualFetch(estate, relation, lockmode, LockWaitBlock,
 								  tid, priorXmax);
 
 	if (copyTuple == NULL)
@@ -1930,12 +1930,15 @@ EvalPlanQual(EState *estate, EPQState *epqstate,
  *	estate - executor state data
  *	relation - table containing tuple
  *	lockmode - requested tuple lock mode
- *	noWait - wait mode to pass to heap_lock_tuple
+ *	wait_policy - requested lock wait policy
  *	*tid - t_ctid from the outdated tuple (ie, next updated version)
  *	priorXmax - t_xmax from the outdated tuple
  *
  * Returns a palloc'd copy of the newest tuple version, or NULL if we find
  * that there is no newest version (ie, the row was deleted not updated).
+ * We also return NULL if the tuple is locked and the wait policy is to skip
+ * such tuples.
+ *
  * If successful, we have locked the newest tuple version, so caller does not
  * need to worry about it changing anymore.
  *
@@ -1943,7 +1946,8 @@ EvalPlanQual(EState *estate, EPQState *epqstate,
  * but we use "int" to avoid having to include heapam.h in executor.h.
  */
 HeapTuple
-EvalPlanQualFetch(EState *estate, Relation relation, int lockmode, bool noWait,
+EvalPlanQualFetch(EState *estate, Relation relation, int lockmode,
+				  LockWaitPolicy wait_policy,
 				  ItemPointer tid, TransactionId priorXmax)
 {
 	HeapTuple	copyTuple = NULL;
@@ -1992,18 +1996,25 @@ EvalPlanQualFetch(EState *estate, Relation relation, int lockmode, bool noWait,
 			if (TransactionIdIsValid(SnapshotDirty.xmax))
 			{
 				ReleaseBuffer(buffer);
-				if (noWait)
+				switch (wait_policy)
 				{
-					if (!ConditionalXactLockTableWait(SnapshotDirty.xmax))
-						ereport(ERROR,
-								(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
-								 errmsg("could not obtain lock on row in relation \"%s\"",
-										RelationGetRelationName(relation))));
+					case LockWaitBlock:
+						XactLockTableWait(SnapshotDirty.xmax,
+										  relation, &tuple.t_data->t_ctid,
+										  XLTW_FetchUpdated);
+						break;
+					case LockWaitSkip:
+						if (!ConditionalXactLockTableWait(SnapshotDirty.xmax))
+							return NULL; /* skip instead of waiting */
+						break;
+					case LockWaitError:
+						if (!ConditionalXactLockTableWait(SnapshotDirty.xmax))
+							ereport(ERROR,
+									(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+									 errmsg("could not obtain lock on row in relation \"%s\"",
+											RelationGetRelationName(relation))));
+						break;
 				}
-				else
-					XactLockTableWait(SnapshotDirty.xmax,
-									  relation, &tuple.t_data->t_ctid,
-									  XLTW_FetchUpdated);
 				continue;		/* loop back to repeat heap_fetch */
 			}
 
@@ -2030,7 +2041,7 @@ EvalPlanQualFetch(EState *estate, Relation relation, int lockmode, bool noWait,
 			 */
 			test = heap_lock_tuple(relation, &tuple,
 								   estate->es_output_cid,
-								   lockmode, noWait,
+								   lockmode, wait_policy,
 								   false, &buffer, &hufd);
 			/* We now have two pins on the buffer, get rid of one */
 			ReleaseBuffer(buffer);
@@ -2076,6 +2087,10 @@ EvalPlanQualFetch(EState *estate, Relation relation, int lockmode, bool noWait,
 					/* tuple was deleted, so give up */
 					return NULL;
 
+				case HeapTupleWouldBlock:
+					ReleaseBuffer(buffer);
+					return NULL;
+
 				default:
 					ReleaseBuffer(buffer);
 					elog(ERROR, "unrecognized heap_lock_tuple status: %u",