From a67697f00b6ea05984544211c8a2d9cfa2fa1cb5 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 2 Mar 2026 03:55:56 +1300 Subject: [PATCH v2 07/19] Use stack buffer in some executor code. Mechanical changes to the allocation of memory used for: * string copies * datums, nulls, Oids, keys and similar values linked to the number of attributes These are all non-escaping values that are not used in recursive processes. --- src/backend/executor/execPartition.c | 7 +++++-- src/backend/executor/execTuples.c | 11 +++++++---- src/backend/executor/nodeAgg.c | 13 +++++++++---- src/backend/executor/nodeHashjoin.c | 14 ++++++++------ src/backend/executor/nodeMemoize.c | 7 +++++-- src/backend/executor/nodeWindowAgg.c | 7 +++++-- src/backend/executor/spi.c | 11 +++++++---- 7 files changed, 46 insertions(+), 24 deletions(-) diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c index bab294f5e91..6cc6d6ea510 100644 --- a/src/backend/executor/execPartition.c +++ b/src/backend/executor/execPartition.c @@ -33,6 +33,7 @@ #include "utils/partcache.h" #include "utils/rls.h" #include "utils/ruleutils.h" +#include "utils/stack_buffer.h" /*----------------------- @@ -2518,6 +2519,8 @@ InitExecPartitionPruneContexts(PartitionPruneState *prunestate, int newidx; bool fix_subplan_map = false; + DECLARE_STACK_BUFFER(); + Assert(prunestate->do_exec_prune); Assert(parent_plan != NULL); estate = parent_plan->state; @@ -2535,7 +2538,7 @@ InitExecPartitionPruneContexts(PartitionPruneState *prunestate, * indexes to new ones. For convenience of initialization, we use * 1-based indexes in this array and leave pruned items as 0. */ - new_subplan_indexes = palloc0_array(int, n_total_subplans); + new_subplan_indexes = stack_buffer_alloc0_array(int, n_total_subplans); newidx = 1; i = -1; while ((i = bms_next_member(initially_valid_subplans, i)) >= 0) @@ -2645,7 +2648,7 @@ InitExecPartitionPruneContexts(PartitionPruneState *prunestate, bms_free(prunestate->other_subplans); prunestate->other_subplans = new_other_subplans; - pfree(new_subplan_indexes); + stack_buffer_free(new_subplan_indexes); } } diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c index b768eae9e53..d105123e3e1 100644 --- a/src/backend/executor/execTuples.c +++ b/src/backend/executor/execTuples.c @@ -68,6 +68,7 @@ #include "utils/builtins.h" #include "utils/expandeddatum.h" #include "utils/lsyscache.h" +#include "utils/stack_buffer.h" #include "utils/typcache.h" static TupleDesc ExecTypeFromTLInternal(List *targetList, @@ -2330,8 +2331,10 @@ BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values) int i; HeapTuple tuple; - dvalues = (Datum *) palloc(natts * sizeof(Datum)); - nulls = (bool *) palloc(natts * sizeof(bool)); + DECLARE_STACK_BUFFER(); + + dvalues = stack_buffer_alloc_array(Datum, natts); + nulls = stack_buffer_alloc_array(bool, natts); /* * Call the "in" function for each non-dropped attribute, even for nulls, @@ -2368,8 +2371,8 @@ BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values) * Release locally palloc'd space. XXX would probably be good to pfree * values of pass-by-reference datums, as well. */ - pfree(dvalues); - pfree(nulls); + stack_buffer_free(dvalues); + stack_buffer_free(nulls); return tuple; } diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index 7d487a165fa..ffc198f526d 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -273,6 +273,7 @@ #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/memutils_memorychunk.h" +#include "utils/stack_buffer.h" #include "utils/syscache.h" #include "utils/tuplesort.h" @@ -4347,10 +4348,12 @@ build_pertrans_for_aggref(AggStatePerTrans pertrans, { Oid *ops; + DECLARE_STACK_BUFFER(); + Assert(numArguments > 0); Assert(list_length(aggref->aggdistinct) == numDistinctCols); - ops = palloc(numDistinctCols * sizeof(Oid)); + ops = stack_buffer_alloc_array(Oid, numDistinctCols); i = 0; foreach(lc, aggref->aggdistinct) @@ -4367,7 +4370,7 @@ build_pertrans_for_aggref(AggStatePerTrans pertrans, ops, pertrans->sortCollations, &aggstate->ss.ps); - pfree(ops); + stack_buffer_free(ops); } pertrans->sortstates = palloc0_array(Tuplesortstate *, numGroupingSets); @@ -4382,11 +4385,13 @@ GetAggInitVal(Datum textInitVal, Oid transtype) char *strInitVal; Datum initVal; + DECLARE_STACK_BUFFER(); + getTypeInputInfo(transtype, &typinput, &typioparam); - strInitVal = TextDatumGetCString(textInitVal); + strInitVal = stack_buffer_text_datum_to_cstring(textInitVal); initVal = OidInputFunctionCall(typinput, strInitVal, typioparam, -1); - pfree(strInitVal); + stack_buffer_free(strInitVal); return initVal; } diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c index 5aa8a09b265..fd7a47d8b85 100644 --- a/src/backend/executor/nodeHashjoin.c +++ b/src/backend/executor/nodeHashjoin.c @@ -171,6 +171,7 @@ #include "miscadmin.h" #include "utils/lsyscache.h" #include "utils/sharedtuplestore.h" +#include "utils/stack_buffer.h" #include "utils/wait_event.h" @@ -826,6 +827,7 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags) ListCell *lc; int nkeys; + DECLARE_STACK_BUFFER(); hjstate->hj_HashTupleSlot = slot; @@ -840,9 +842,9 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags) */ nkeys = list_length(node->hashoperators); - outer_hashfuncid = palloc_array(Oid, nkeys); - inner_hashfuncid = palloc_array(Oid, nkeys); - hash_strict = palloc_array(bool, nkeys); + outer_hashfuncid = stack_buffer_alloc_array(Oid, nkeys); + inner_hashfuncid = stack_buffer_alloc_array(Oid, nkeys); + hash_strict = stack_buffer_alloc_array(bool, nkeys); /* * Determine the hash function for each side of the join for the given @@ -905,9 +907,9 @@ ExecInitHashJoin(HashJoin *node, EState *estate, int eflags) } /* no need to keep these */ - pfree(outer_hashfuncid); - pfree(inner_hashfuncid); - pfree(hash_strict); + stack_buffer_free(outer_hashfuncid); + stack_buffer_free(inner_hashfuncid); + stack_buffer_free(hash_strict); } /* diff --git a/src/backend/executor/nodeMemoize.c b/src/backend/executor/nodeMemoize.c index edf52efd4c3..09a5e674dd7 100644 --- a/src/backend/executor/nodeMemoize.c +++ b/src/backend/executor/nodeMemoize.c @@ -74,6 +74,7 @@ #include "miscadmin.h" #include "utils/datum.h" #include "utils/lsyscache.h" +#include "utils/stack_buffer.h" /* States of the ExecMemoize state machine */ #define MEMO_CACHE_LOOKUP 1 /* Attempt to perform a cache lookup */ @@ -958,6 +959,8 @@ ExecInitMemoize(Memoize *node, EState *estate, int eflags) int nkeys; Oid *eqfuncoids; + DECLARE_STACK_BUFFER(); + /* check for unsupported flags */ Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK))); @@ -1006,7 +1009,7 @@ ExecInitMemoize(Memoize *node, EState *estate, int eflags) * data */ mstate->hashfunctions = (FmgrInfo *) palloc(nkeys * sizeof(FmgrInfo)); - eqfuncoids = palloc(nkeys * sizeof(Oid)); + eqfuncoids = stack_buffer_alloc_array(Oid, nkeys); for (i = 0; i < nkeys; i++) { @@ -1033,7 +1036,7 @@ ExecInitMemoize(Memoize *node, EState *estate, int eflags) node->param_exprs, (PlanState *) mstate); - pfree(eqfuncoids); + stack_buffer_free(eqfuncoids); mstate->mem_used = 0; /* Limit the total memory consumed by the cache to this */ diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c index d9b64b0f465..ed3744f5493 100644 --- a/src/backend/executor/nodeWindowAgg.c +++ b/src/backend/executor/nodeWindowAgg.c @@ -52,6 +52,7 @@ #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/regproc.h" +#include "utils/stack_buffer.h" #include "utils/syscache.h" #include "windowapi.h" @@ -3163,11 +3164,13 @@ GetAggInitVal(Datum textInitVal, Oid transtype) char *strInitVal; Datum initVal; + DECLARE_STACK_BUFFER(); + getTypeInputInfo(transtype, &typinput, &typioparam); - strInitVal = TextDatumGetCString(textInitVal); + strInitVal = stack_buffer_text_datum_to_cstring(textInitVal); initVal = OidInputFunctionCall(typinput, strInitVal, typioparam, -1); - pfree(strInitVal); + stack_buffer_free(strInitVal); return initVal; } diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c index 3019a3b2b97..dbbb710f877 100644 --- a/src/backend/executor/spi.c +++ b/src/backend/executor/spi.c @@ -31,6 +31,7 @@ #include "utils/memutils.h" #include "utils/rel.h" #include "utils/snapmgr.h" +#include "utils/stack_buffer.h" #include "utils/syscache.h" #include "utils/typcache.h" @@ -1113,6 +1114,8 @@ SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum, bool *n; int i; + DECLARE_STACK_BUFFER(); + if (rel == NULL || tuple == NULL || natts < 0 || attnum == NULL || Values == NULL) { SPI_result = SPI_ERROR_ARGUMENT; @@ -1130,8 +1133,8 @@ SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum, SPI_result = 0; numberOfAttributes = rel->rd_att->natts; - v = palloc_array(Datum, numberOfAttributes); - n = palloc_array(bool, numberOfAttributes); + v = stack_buffer_alloc_array(Datum, numberOfAttributes); + n = stack_buffer_alloc_array(bool, numberOfAttributes); /* fetch old values and nulls */ heap_deform_tuple(tuple, rel->rd_att, v, n); @@ -1163,8 +1166,8 @@ SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum, SPI_result = SPI_ERROR_NOATTRIBUTE; } - pfree(v); - pfree(n); + stack_buffer_free(v); + stack_buffer_free(n); MemoryContextSwitchTo(oldcxt); -- 2.53.0