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author Jeff Davis <jdavis@postgresql.org>

Thu, 6 Feb 2020 19:49:56 +0000 (11:49 -0800)

committer Jeff Davis <jdavis@postgresql.org>

Thu, 6 Feb 2020 19:49:56 +0000 (11:49 -0800)

Consolidate the calculations for hash table size estimation. This will
help with upcoming Hash Aggregation work that will add additional call
sites.

src/backend/executor/nodeAgg.c patch | blob | blame | history

src/backend/optimizer/plan/planner.c patch | blob | blame | history

src/backend/utils/adt/selfuncs.c patch | blob | blame | history

src/include/executor/nodeAgg.h patch | blob | blame | history

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c

index 9073395eacfd363c8a8f57c1b01baf953362a88d..b7f49ceddf8c7258305ac144a10d831bc745c8a5 100644 (file)

--- a/src/backend/executor/nodeAgg.c

+++ b/src/backend/executor/nodeAgg.c

@@ -1422,24 +1422,17 @@ find_hash_columns(AggState *aggstate)

}

- * Estimate per-hash-table-entry overhead for the planner.

- *

- * Note that the estimate does not include space for pass-by-reference

- * transition data values, nor for the representative tuple of each group.

- * Nor does this account of the target fill-factor and growth policy of the

- * hash table.

+ * Estimate per-hash-table-entry overhead.

Size

-hash_agg_entry_size(int numAggs)

+hash_agg_entry_size(int numAggs, Size tupleWidth, Size transitionSpace)

{

- Size entrysize;

- /* This must match build_hash_table */

- entrysize = sizeof(TupleHashEntryData) +

- numAggs * sizeof(AggStatePerGroupData);

- entrysize = MAXALIGN(entrysize);

- return entrysize;

+ return

+ MAXALIGN(SizeofMinimalTupleHeader) +

+ MAXALIGN(tupleWidth) +

+ MAXALIGN(sizeof(TupleHashEntryData) +

+ numAggs * sizeof(AggStatePerGroupData)) +

+ transitionSpace;

}

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c

index d6f21535937ba4937aa25d5143eb63070ef8d7b4..b44efd6314c5edd3a21dbc681ebf0747516910cc 100644 (file)

--- a/src/backend/optimizer/plan/planner.c

+++ b/src/backend/optimizer/plan/planner.c

@@ -4867,13 +4867,8 @@ create_distinct_paths(PlannerInfo *root,

allow_hash = false; /* policy-based decision not to hash */

else

{

- Size hashentrysize;

- /* Estimate per-hash-entry space at tuple width... */

- hashentrysize = MAXALIGN(cheapest_input_path->pathtarget->width) +

- MAXALIGN(SizeofMinimalTupleHeader);

- /* plus the per-hash-entry overhead */

- hashentrysize += hash_agg_entry_size(0);

+ Size hashentrysize = hash_agg_entry_size(

+ 0, cheapest_input_path->pathtarget->width, 0);

/* Allow hashing only if hashtable is predicted to fit in work_mem */

allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L);

diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c

index 7c6f0574b3720d632270ab213c80d8f9effc3dfa..0be26fe03780c89f15642dd98ecea2eaa0db42a3 100644 (file)

--- a/src/backend/utils/adt/selfuncs.c

+++ b/src/backend/utils/adt/selfuncs.c

@@ -3526,16 +3526,8 @@ double

estimate_hashagg_tablesize(Path *path, const AggClauseCosts *agg_costs,

double dNumGroups)

{

- Size hashentrysize;

- /* Estimate per-hash-entry space at tuple width... */

- hashentrysize = MAXALIGN(path->pathtarget->width) +

- MAXALIGN(SizeofMinimalTupleHeader);

- /* plus space for pass-by-ref transition values... */

- hashentrysize += agg_costs->transitionSpace;

- /* plus the per-hash-entry overhead */

- hashentrysize += hash_agg_entry_size(agg_costs->numAggs);

+ Size hashentrysize = hash_agg_entry_size(

+ agg_costs->numAggs, path->pathtarget->width, agg_costs->transitionSpace);

* Note that this disregards the effect of fill-factor and growth policy

diff --git a/src/include/executor/nodeAgg.h b/src/include/executor/nodeAgg.h

index 2fe82da6ff734e7654102c7f36c16f0033dc584a..264916f9a921c33abcbd5cfaf96a45b4e53db22e 100644 (file)

--- a/src/include/executor/nodeAgg.h

+++ b/src/include/executor/nodeAgg.h

@@ -309,6 +309,7 @@ extern AggState *ExecInitAgg(Agg *node, EState *estate, int eflags);

extern void ExecEndAgg(AggState *node);

extern void ExecReScanAgg(AggState *node);

-extern Size hash_agg_entry_size(int numAggs);

+extern Size hash_agg_entry_size(int numAggs, Size tupleWidth,

+ Size transitionSpace);

#endif /* NODEAGG_H */

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