diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 59b38d00ed..b9a012512d 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -4340,11 +4340,13 @@ GetAfterTriggersStoreSlot(AfterTriggersTableData *table,
 		MemoryContext	oldcxt;

 		/*
-		 * We only need this slot only until AfterTriggerEndQuery, but making
-		 * it last till end-of-subxact is good enough.  It'll be freed by
-		 * AfterTriggerFreeQuery().
+		 * We need this slot only until AfterTriggerEndQuery, but making it
+		 * last till end-of-subxact is good enough.  It'll be freed by
+		 * AfterTriggerFreeQuery().  However, the passed-in tupdesc might have
+		 * a different lifespan, so we'd better make a copy of that.
 		 */
 		oldcxt = MemoryContextSwitchTo(CurTransactionContext);
+		tupdesc = CreateTupleDescCopy(tupdesc);
 		table->storeslot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual);
 		MemoryContextSwitchTo(oldcxt);
 	}