diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c
index 83834e0c2f5..5fa9018c7dc 100644
--- a/src/backend/access/heap/tuptoaster.c
+++ b/src/backend/access/heap/tuptoaster.c
@@ -1650,7 +1650,9 @@ toast_delete_datum(Relation rel, Datum value)
 /* ----------
  * toastrel_valueid_exists -
  *
- *	Test whether a toast value with the given ID exists in the toast relation
+ *	Test whether a toast value with the given ID exists in the toast relation.
+ *	For safety, we consider a value to exist if there are either live or dead
+ *	toast rows with that ID; see notes for GetNewOid().
  * ----------
  */
 static bool
@@ -1682,7 +1684,7 @@ toastrel_valueid_exists(Relation toastrel, Oid valueid)
 	 */
 	toastscan = systable_beginscan(toastrel,
 								   RelationGetRelid(toastidxs[validIndex]),
-								   true, SnapshotToast, 1, &toastkey);
+								   true, SnapshotAny, 1, &toastkey);
 
 	if (systable_getnext(toastscan) != NULL)
 		result = true;
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 2eb2c2fddf6..81a377179a4 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -270,8 +270,12 @@ IsSharedRelation(Oid relationId)
  * managed to cycle through 2^32 OIDs and generate the same OID before we
  * finish inserting our row.  This seems unlikely to be a problem.  Note
  * that if we had to *commit* the row to end the race condition, the risk
- * would be rather higher; therefore we use SnapshotDirty in the test,
- * so that we will see uncommitted rows.
+ * would be rather higher; therefore we use SnapshotAny in the test, so that
+ * we will see uncommitted rows.  (We used to use SnapshotDirty, but that has
+ * the disadvantage that it ignores recently-deleted rows, creating a risk
+ * of transient conflicts for as long as our own MVCC snapshots think a
+ * recently-deleted row is live.  The risk is far higher when selecting TOAST
+ * OIDs, because SnapshotToast considers dead rows as active indefinitely.)
  */
 Oid
 GetNewOid(Relation relation)
@@ -324,13 +328,10 @@ Oid
 GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
 {
 	Oid			newOid;
-	SnapshotData SnapshotDirty;
 	SysScanDesc scan;
 	ScanKeyData key;
 	bool		collides;
 
-	InitDirtySnapshot(SnapshotDirty);
-
 	/* Generate new OIDs until we find one not in the table */
 	do
 	{
@@ -343,9 +344,9 @@ GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
 					BTEqualStrategyNumber, F_OIDEQ,
 					ObjectIdGetDatum(newOid));
 
-		/* see notes above about using SnapshotDirty */
+		/* see notes above about using SnapshotAny */
 		scan = systable_beginscan(relation, indexId, true,
-								  &SnapshotDirty, 1, &key);
+								  SnapshotAny, 1, &key);
 
 		collides = HeapTupleIsValid(systable_getnext(scan));