From 9eca4c6277c63f4f8f28afced07ee13c65bfb36e Mon Sep 17 00:00:00 2001 From: Alexander Pyhalov Date: Tue, 16 Dec 2025 18:46:27 +0300 Subject: [PATCH 1/3] Limit batch_size for foreign insert with work_mem Option batch_size can be set on foreign server level. It can be very optimistic even for one table with different tuple lengths. To prevent large memory usage limit effective batch size with work_mem. --- src/backend/executor/nodeModifyTable.c | 15 ++++++++++++--- src/include/nodes/execnodes.h | 1 + 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c index 7d7411a7056..9495d9b04bb 100644 --- a/src/backend/executor/nodeModifyTable.c +++ b/src/backend/executor/nodeModifyTable.c @@ -943,12 +943,18 @@ ExecInsert(ModifyTableContext *context, if (resultRelInfo->ri_BatchSize > 1) { bool flushed = false; + Size tuple_len; + + /* Compute length of the current tuple */ + slot_getallattrs(slot); + tuple_len = heap_compute_data_size(slot->tts_tupleDescriptor, slot->tts_values, slot->tts_isnull); /* - * When we've reached the desired batch size, perform the - * insertion. + * When we've reached the desired batch size or exceeded work_mem, + * perform the insertion. */ - if (resultRelInfo->ri_NumSlots == resultRelInfo->ri_BatchSize) + if (resultRelInfo->ri_NumSlots == resultRelInfo->ri_BatchSize || + ((tuple_len + resultRelInfo->ri_BatchMemoryUsed > work_mem * 1024) && (resultRelInfo->ri_NumSlots > 0))) { ExecBatchInsert(mtstate, resultRelInfo, resultRelInfo->ri_Slots, @@ -1019,6 +1025,8 @@ ExecInsert(ModifyTableContext *context, resultRelInfo)); resultRelInfo->ri_NumSlots++; + /* Batch size can grow up to tuple length even if it exceeds work_mem. */ + resultRelInfo->ri_BatchMemoryUsed += tuple_len; MemoryContextSwitchTo(oldContext); @@ -1418,6 +1426,7 @@ ExecBatchInsert(ModifyTableState *mtstate, ExecClearTuple(planSlots[i]); } resultRelInfo->ri_NumSlots = 0; + resultRelInfo->ri_BatchMemoryUsed = 0; } /* diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index f8053d9e572..33d3eb06891 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -544,6 +544,7 @@ typedef struct ResultRelInfo int ri_NumSlots; /* number of slots in the array */ int ri_NumSlotsInitialized; /* number of initialized slots */ int ri_BatchSize; /* max slots inserted in a single batch */ + int ri_BatchMemoryUsed; /* memory used by batch */ TupleTableSlot **ri_Slots; /* input tuples for batch insert */ TupleTableSlot **ri_PlanSlots; -- 2.43.0