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| author | Jeff Davis <jdavis@postgresql.org> | 2020-09-15 21:16:31 -0700 |
|---|---|---|
| committer | Jeff Davis <jdavis@postgresql.org> | 2020-09-15 21:18:22 -0700 |
| commit | 3bd35d4f516adfc492360b20e72911949c961e47 (patch) | |
| tree | 89736eb4c69d2a83d8da538d1d09bcede9b9c24c /src | |
| parent | 69bd60672af63eaa8b19cdcea175df5ff172e80e (diff) | |
| download | postgresql-3bd35d4f516adfc492360b20e72911949c961e47.tar.gz postgresql-3bd35d4f516adfc492360b20e72911949c961e47.zip | |
HashAgg: release write buffers sooner by rewinding tape.
This was an oversight. The purpose of 7fdd919ae7 was to avoid keeping
tape buffers around unnecessisarily, but HashAgg didn't rewind early
enough.
Reviewed-by: Peter Geoghegan
Discussion: https://postgr.es/m/1fb1151c2cddf8747d14e0532da283c3f97e2685.camel@j-davis.com
Backpatch-through: 13
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/executor/nodeAgg.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index f74d4841f17..28802e6588d 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -2639,8 +2639,6 @@ agg_refill_hash_table(AggState *aggstate) */ hashagg_recompile_expressions(aggstate, true, true); - LogicalTapeRewindForRead(tapeinfo->tapeset, batch->input_tapenum, - HASHAGG_READ_BUFFER_SIZE); for (;;) { TupleTableSlot *spillslot = aggstate->hash_spill_rslot; @@ -2923,6 +2921,7 @@ hashagg_tapeinfo_assign(HashTapeInfo *tapeinfo, int *partitions, static void hashagg_tapeinfo_release(HashTapeInfo *tapeinfo, int tapenum) { + /* rewinding frees the buffer while not in use */ LogicalTapeRewindForWrite(tapeinfo->tapeset, tapenum); if (tapeinfo->freetapes_alloc == tapeinfo->nfreetapes) { @@ -3152,6 +3151,7 @@ hashagg_spill_finish(AggState *aggstate, HashAggSpill *spill, int setno) for (i = 0; i < spill->npartitions; i++) { + LogicalTapeSet *tapeset = aggstate->hash_tapeinfo->tapeset; int tapenum = spill->partitions[i]; HashAggBatch *new_batch; double cardinality; @@ -3163,9 +3163,13 @@ hashagg_spill_finish(AggState *aggstate, HashAggSpill *spill, int setno) cardinality = estimateHyperLogLog(&spill->hll_card[i]); freeHyperLogLog(&spill->hll_card[i]); - new_batch = hashagg_batch_new(aggstate->hash_tapeinfo->tapeset, - tapenum, setno, spill->ntuples[i], - cardinality, used_bits); + /* rewinding frees the buffer while not in use */ + LogicalTapeRewindForRead(tapeset, tapenum, + HASHAGG_READ_BUFFER_SIZE); + + new_batch = hashagg_batch_new(tapeset, tapenum, setno, + spill->ntuples[i], cardinality, + used_bits); aggstate->hash_batches = lcons(new_batch, aggstate->hash_batches); aggstate->hash_batches_used++; } |