postgres.git / summary / log / commit / refs

commit    650663b4cb4714a34d7171981de4392486a85f86
Author:   Tomas Vondra <tomas.vondra@postgresql.org>
Date:     Thu Aug 12 19:32:53 2021 +0000
First released in: 15.0, 14.0

    Use appropriate tuple descriptor in FDW batching
    
    The FDW batching code was using the same tuple descriptor both for all
    slots (regular and plan slots), but that's incorrect - the subplan may
    use a different descriptor. Currently this is benign, because batching
    is used only for INSERTs, and in that case the descriptors always match.
    But that would change if we allow batching UPDATEs.
    
    Fix by copying the appropriate tuple descriptor. Backpatch to 14, where
    the FDW batching was implemented.
    
    Author: Amit Langote
    Backpatch-through: 14, where FDW batching was added
    Discussion: https://postgr.es/m/CA%2BHiwqEWd5B0-e-RvixGGUrNvGkjH2s4m95%3DJcwUnyV%3Df0rAKQ%40mail.gmail.com


 src/backend/executor/nodeModifyTable.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index c24684aa6fe..d328856ae5b 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -709,17 +709,19 @@ ExecInsert(ModifyTableState *mtstate,
 			 * keep them across batches. To mitigate an inefficiency in how
 			 * resource owner handles objects with many references (as with
 			 * many slots all referencing the same tuple descriptor) we copy
-			 * the tuple descriptor for each slot.
+			 * the appropriate tuple descriptor for each slot.
 			 */
 			if (resultRelInfo->ri_NumSlots >= resultRelInfo->ri_NumSlotsInitialized)
 			{
 				TupleDesc	tdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
+				TupleDesc	plan_tdesc =
+					CreateTupleDescCopy(planSlot->tts_tupleDescriptor);
 
 				resultRelInfo->ri_Slots[resultRelInfo->ri_NumSlots] =
 					MakeSingleTupleTableSlot(tdesc, slot->tts_ops);
 
 				resultRelInfo->ri_PlanSlots[resultRelInfo->ri_NumSlots] =
-					MakeSingleTupleTableSlot(tdesc, planSlot->tts_ops);
+					MakeSingleTupleTableSlot(plan_tdesc, planSlot->tts_ops);
 
 				/* remember how many batch slots we initialized */
 				resultRelInfo->ri_NumSlotsInitialized++;


[parent: ba958299eaf3]