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Injection points for hash aggregation.

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Requires adding a guard against shift-by-32. Previously, that was
impossible because the number of partitions was always greater than 1,
but a new injection point can force the number of partitions to 1.

Discussion: https://postgr.es/m/ff4e59305e5d689e03cd256a736348d3e7958f8f.camel@j-davis.com
This commit is contained in:
Jeff Davis 2025-02-11 11:26:25 -08:00
parent 052026c9b9
commit 38172d1856
5 changed files with 141 additions and 4 deletions
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48
src/backend/executor/nodeAgg.c
View File

@ -269,6 +269,7 @@
#include "utils/datum.h"
#include "utils/dynahash.h"
#include "utils/expandeddatum.h"
#include "utils/injection_point.h"
#include "utils/logtape.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
@ -1489,6 +1490,14 @@ build_hash_tables(AggState *aggstate)
perhash->aggnode->numGroups,
memory);
#ifdef USE_INJECTION_POINTS
if (IS_INJECTION_POINT_ATTACHED("hash-aggregate-oversize-table"))
{
nbuckets = memory / sizeof(TupleHashEntryData);
INJECTION_POINT_CACHED("hash-aggregate-oversize-table");
}
#endif
build_hash_table(aggstate, setno, nbuckets);
}
@ -1860,6 +1869,18 @@ hash_agg_check_limits(AggState *aggstate)
true);
Size hashkey_mem = MemoryContextMemAllocated(aggstate->hashcontext->ecxt_per_tuple_memory,
true);
bool do_spill = false;
#ifdef USE_INJECTION_POINTS
if (ngroups >= 1000)
{
if (IS_INJECTION_POINT_ATTACHED("hash-aggregate-spill-1000"))
{
do_spill = true;
INJECTION_POINT_CACHED("hash-aggregate-spill-1000");
}
}
#endif
/*
* Don't spill unless there's at least one group in the hash table so we
@ -1869,8 +1890,11 @@ hash_agg_check_limits(AggState *aggstate)
(meta_mem + hashkey_mem > aggstate->hash_mem_limit ||
ngroups > aggstate->hash_ngroups_limit))
{
hash_agg_enter_spill_mode(aggstate);
do_spill = true;
}
if (do_spill)
hash_agg_enter_spill_mode(aggstate);
}
/*
@ -1881,6 +1905,7 @@ hash_agg_check_limits(AggState *aggstate)
static void
hash_agg_enter_spill_mode(AggState *aggstate)
{
INJECTION_POINT("hash-aggregate-enter-spill-mode");
aggstate->hash_spill_mode = true;
hashagg_recompile_expressions(aggstate, aggstate->table_filled, true);
@ -2652,6 +2677,7 @@ agg_refill_hash_table(AggState *aggstate)
*/
hashagg_recompile_expressions(aggstate, true, true);
INJECTION_POINT("hash-aggregate-process-batch");
for (;;)
{
TupleTableSlot *spillslot = aggstate->hash_spill_rslot;
@ -2900,6 +2926,15 @@ hashagg_spill_init(HashAggSpill *spill, LogicalTapeSet *tapeset, int used_bits,
npartitions = hash_choose_num_partitions(input_groups, hashentrysize,
used_bits, &partition_bits);
#ifdef USE_INJECTION_POINTS
if (IS_INJECTION_POINT_ATTACHED("hash-aggregate-single-partition"))
{
npartitions = 1;
partition_bits = 0;
INJECTION_POINT_CACHED("hash-aggregate-single-partition");
}
#endif
spill->partitions = palloc0(sizeof(LogicalTape *) * npartitions);
spill->ntuples = palloc0(sizeof(int64) * npartitions);
spill->hll_card = palloc0(sizeof(hyperLogLogState) * npartitions);
@ -2908,7 +2943,10 @@ hashagg_spill_init(HashAggSpill *spill, LogicalTapeSet *tapeset, int used_bits,
spill->partitions[i] = LogicalTapeCreate(tapeset);
spill->shift = 32 - used_bits - partition_bits;
spill->mask = (npartitions - 1) << spill->shift;
if (spill->shift < 32)
spill->mask = (npartitions - 1) << spill->shift;
else
spill->mask = 0;
spill->npartitions = npartitions;
for (int i = 0; i < npartitions; i++)
@ -2957,7 +2995,11 @@ hashagg_spill_tuple(AggState *aggstate, HashAggSpill *spill,
tuple = ExecFetchSlotMinimalTuple(spillslot, &shouldFree);
partition = (hash & spill->mask) >> spill->shift;
if (spill->shift < 32)
partition = (hash & spill->mask) >> spill->shift;
else
partition = 0;
spill->ntuples[partition]++;
/*

2
src/test/modules/injection_points/Makefile
View File

@ -11,7 +11,7 @@ EXTENSION = injection_points
DATA = injection_points--1.0.sql
PGFILEDESC = "injection_points - facility for injection points"
REGRESS = injection_points reindex_conc
REGRESS = injection_points hashagg reindex_conc
REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
ISOLATION = basic inplace syscache-update-pruned

68
src/test/modules/injection_points/expected/hashagg.out Normal file
View File

@ -0,0 +1,68 @@
-- Test for hash aggregation
CREATE EXTENSION injection_points;
SELECT injection_points_set_local();
injection_points_set_local
----------------------------
(1 row)
SELECT injection_points_attach('hash-aggregate-enter-spill-mode', 'notice');
injection_points_attach
-------------------------
(1 row)
SELECT injection_points_attach('hash-aggregate-process-batch', 'notice');
injection_points_attach
-------------------------
(1 row)
-- force partition fan-out to 1
SELECT injection_points_attach('hash-aggregate-single-partition', 'notice');
injection_points_attach
-------------------------
(1 row)
-- force spilling after 1000 groups
SELECT injection_points_attach('hash-aggregate-spill-1000', 'notice');
injection_points_attach
-------------------------
(1 row)
CREATE TABLE hashagg_ij(x INTEGER);
INSERT INTO hashagg_ij SELECT g FROM generate_series(1,5100) g;
SET max_parallel_workers=0;
SET max_parallel_workers_per_gather=0;
SET enable_sort=FALSE;
SET work_mem='4MB';
SELECT COUNT(*) FROM (SELECT DISTINCT x FROM hashagg_ij) s;
NOTICE: notice triggered for injection point hash-aggregate-spill-1000
NOTICE: notice triggered for injection point hash-aggregate-enter-spill-mode
NOTICE: notice triggered for injection point hash-aggregate-single-partition
NOTICE: notice triggered for injection point hash-aggregate-process-batch
NOTICE: notice triggered for injection point hash-aggregate-spill-1000
NOTICE: notice triggered for injection point hash-aggregate-enter-spill-mode
NOTICE: notice triggered for injection point hash-aggregate-single-partition
NOTICE: notice triggered for injection point hash-aggregate-process-batch
NOTICE: notice triggered for injection point hash-aggregate-spill-1000
NOTICE: notice triggered for injection point hash-aggregate-enter-spill-mode
NOTICE: notice triggered for injection point hash-aggregate-single-partition
NOTICE: notice triggered for injection point hash-aggregate-process-batch
NOTICE: notice triggered for injection point hash-aggregate-spill-1000
NOTICE: notice triggered for injection point hash-aggregate-enter-spill-mode
NOTICE: notice triggered for injection point hash-aggregate-single-partition
NOTICE: notice triggered for injection point hash-aggregate-process-batch
NOTICE: notice triggered for injection point hash-aggregate-spill-1000
NOTICE: notice triggered for injection point hash-aggregate-enter-spill-mode
NOTICE: notice triggered for injection point hash-aggregate-single-partition
NOTICE: notice triggered for injection point hash-aggregate-process-batch
count
-------
5100
(1 row)
DROP TABLE hashagg_ij;
DROP EXTENSION injection_points;

1
src/test/modules/injection_points/meson.build
View File

@ -35,6 +35,7 @@ tests += {
'regress': {
'sql': [
'injection_points',
'hashagg',
'reindex_conc',
],
'regress_args': ['--dlpath', meson.build_root() / 'src/test/regress'],

26
src/test/modules/injection_points/sql/hashagg.sql Normal file
View File

@ -0,0 +1,26 @@
-- Test for hash aggregation
CREATE EXTENSION injection_points;
SELECT injection_points_set_local();
SELECT injection_points_attach('hash-aggregate-enter-spill-mode', 'notice');
SELECT injection_points_attach('hash-aggregate-process-batch', 'notice');
-- force partition fan-out to 1
SELECT injection_points_attach('hash-aggregate-single-partition', 'notice');
-- force spilling after 1000 groups
SELECT injection_points_attach('hash-aggregate-spill-1000', 'notice');
CREATE TABLE hashagg_ij(x INTEGER);
INSERT INTO hashagg_ij SELECT g FROM generate_series(1,5100) g;
SET max_parallel_workers=0;
SET max_parallel_workers_per_gather=0;
SET enable_sort=FALSE;
SET work_mem='4MB';
SELECT COUNT(*) FROM (SELECT DISTINCT x FROM hashagg_ij) s;
DROP TABLE hashagg_ij;
DROP EXTENSION injection_points;