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Fix EXPLAIN ANALYZE for parallel HashAgg plans

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Since 1f39bce02, HashAgg nodes have had the ability to spill to disk when
memory consumption exceeds work_mem. That commit added new properties to
EXPLAIN ANALYZE to show the maximum memory usage and disk usage, however,
it didn't quite go as far as showing that information for parallel
workers.  Since workers may have experienced something very different from
the main process, we should show this information per worker, as is done
in Sort.

Reviewed-by: Justin Pryzby
Reviewed-by: Jeff Davis
Discussion: https://postgr.es/m/CAApHDvpEKbfZa18mM1TD7qV6PG+w97pwCWq5tVD0dX7e11gRJw@mail.gmail.com
Backpatch-through: 13, where the hashagg spilling code was added.
This commit is contained in:
David Rowley
2020-06-19 17:24:27 +12:00
parent f219167910
commit 9bdb300ded
5 changed files with 245 additions and 18 deletions
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112
src/backend/commands/explain.c
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@ -3051,29 +3051,111 @@ show_hashagg_info(AggState *aggstate, ExplainState *es)
Agg *agg = (Agg *) aggstate->ss.ps.plan;
int64 memPeakKb = (aggstate->hash_mem_peak + 1023) / 1024;
Assert(IsA(aggstate, AggState));
if (agg->aggstrategy != AGG_HASHED &&
agg->aggstrategy != AGG_MIXED)
return;
if (es->costs && aggstate->hash_planned_partitions > 0)
if (es->format != EXPLAIN_FORMAT_TEXT)
{
ExplainPropertyInteger("Planned Partitions", NULL,
aggstate->hash_planned_partitions, es);
if (es->costs && aggstate->hash_planned_partitions > 0)
{
ExplainPropertyInteger("Planned Partitions", NULL,
aggstate->hash_planned_partitions, es);
}
if (!es->analyze)
return;
/* EXPLAIN ANALYZE */
ExplainPropertyInteger("Peak Memory Usage", "kB", memPeakKb, es);
if (aggstate->hash_batches_used > 0)
{
ExplainPropertyInteger("Disk Usage", "kB",
aggstate->hash_disk_used, es);
ExplainPropertyInteger("HashAgg Batches", NULL,
aggstate->hash_batches_used, es);
}
}
else
{
bool gotone = false;
if (es->costs && aggstate->hash_planned_partitions > 0)
{
ExplainIndentText(es);
appendStringInfo(es->str, "Planned Partitions: %d",
aggstate->hash_planned_partitions);
gotone = true;
}
if (!es->analyze)
{
if (gotone)
appendStringInfoChar(es->str, '\n');
return;
}
if (!gotone)
ExplainIndentText(es);
else
appendStringInfoString(es->str, " ");
appendStringInfo(es->str, "Peak Memory Usage: " INT64_FORMAT " kB",
memPeakKb);
if (aggstate->hash_batches_used > 0)
appendStringInfo(es->str, " Disk Usage: " UINT64_FORMAT " kB HashAgg Batches: %d",
aggstate->hash_disk_used,
aggstate->hash_batches_used);
appendStringInfoChar(es->str, '\n');
}
if (!es->analyze)
return;
/* EXPLAIN ANALYZE */
ExplainPropertyInteger("Peak Memory Usage", "kB", memPeakKb, es);
if (aggstate->hash_batches_used > 0)
/* Display stats for each parallel worker */
if (es->analyze && aggstate->shared_info != NULL)
{
ExplainPropertyInteger("Disk Usage", "kB",
aggstate->hash_disk_used, es);
ExplainPropertyInteger("HashAgg Batches", NULL,
aggstate->hash_batches_used, es);
for (int n = 0; n < aggstate->shared_info->num_workers; n++)
{
AggregateInstrumentation *sinstrument;
uint64 hash_disk_used;
int hash_batches_used;
sinstrument = &aggstate->shared_info->sinstrument[n];
hash_disk_used = sinstrument->hash_disk_used;
hash_batches_used = sinstrument->hash_batches_used;
memPeakKb = (sinstrument->hash_mem_peak + 1023) / 1024;
if (es->workers_state)
ExplainOpenWorker(n, es);
if (es->format == EXPLAIN_FORMAT_TEXT)
{
ExplainIndentText(es);
appendStringInfo(es->str, "Peak Memory Usage: " INT64_FORMAT " kB",
memPeakKb);
if (hash_batches_used > 0)
appendStringInfo(es->str, " Disk Usage: " UINT64_FORMAT " kB HashAgg Batches: %d",
hash_disk_used, hash_batches_used);
appendStringInfoChar(es->str, '\n');
}
else
{
ExplainPropertyInteger("Peak Memory Usage", "kB", memPeakKb,
es);
if (hash_batches_used > 0)
{
ExplainPropertyInteger("Disk Usage", "kB", hash_disk_used,
es);
ExplainPropertyInteger("HashAgg Batches", NULL,
hash_batches_used, es);
}
}
if (es->workers_state)
ExplainCloseWorker(n, es);
}
}
}