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Fix LookupTupleHashEntryHash() pipeline-stall issue.

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Refactor hash lookups in nodeAgg.c to improve performance.

Author: Andres Freund and Jeff Davis
Discussion: https://postgr.es/m/20200612213715.op4ye4q7gktqvpuo%40alap3.anarazel.de
Backpatch-through: 13
This commit is contained in:
Jeff Davis
2020-07-26 14:55:52 -07:00
parent 56788d2156
commit 200f6100a9
6 changed files with 107 additions and 103 deletions
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29
src/backend/executor/execGrouping.c
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@ -22,11 +22,11 @@
#include "utils/memutils.h"
static int TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2);
static uint32 TupleHashTableHash_internal(struct tuplehash_hash *tb,
const MinimalTuple tuple);
static TupleHashEntry LookupTupleHashEntry_internal(TupleHashTable hashtable,
TupleTableSlot *slot,
bool *isnew, uint32 hash);
static inline uint32 TupleHashTableHash_internal(struct tuplehash_hash *tb,
const MinimalTuple tuple);
static inline TupleHashEntry LookupTupleHashEntry_internal(TupleHashTable hashtable,
TupleTableSlot *slot,
bool *isnew, uint32 hash);
/*
* Define parameters for tuple hash table code generation. The interface is
@ -291,6 +291,9 @@ ResetTupleHashTable(TupleHashTable hashtable)
* If isnew is NULL, we do not create new entries; we return NULL if no
* match is found.
*
* If hash is not NULL, we set it to the calculated hash value. This allows
* callers access to the hash value even if no entry is returned.
*
* If isnew isn't NULL, then a new entry is created if no existing entry
* matches. On return, *isnew is true if the entry is newly created,
* false if it existed already. ->additional_data in the new entry has
@ -298,11 +301,11 @@ ResetTupleHashTable(TupleHashTable hashtable)
*/
TupleHashEntry
LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
bool *isnew)
bool *isnew, uint32 *hash)
{
TupleHashEntry entry;
MemoryContext oldContext;
uint32 hash;
uint32 local_hash;
/* Need to run the hash functions in short-lived context */
oldContext = MemoryContextSwitchTo(hashtable->tempcxt);
@ -312,8 +315,13 @@ LookupTupleHashEntry(TupleHashTable hashtable, TupleTableSlot *slot,
hashtable->in_hash_funcs = hashtable->tab_hash_funcs;
hashtable->cur_eq_func = hashtable->tab_eq_func;
hash = TupleHashTableHash_internal(hashtable->hashtab, NULL);
entry = LookupTupleHashEntry_internal(hashtable, slot, isnew, hash);
local_hash = TupleHashTableHash_internal(hashtable->hashtab, NULL);
entry = LookupTupleHashEntry_internal(hashtable, slot, isnew, local_hash);
if (hash != NULL)
*hash = local_hash;
Assert(entry == NULL || entry->hash == local_hash);
MemoryContextSwitchTo(oldContext);
@ -362,6 +370,7 @@ LookupTupleHashEntryHash(TupleHashTable hashtable, TupleTableSlot *slot,
hashtable->cur_eq_func = hashtable->tab_eq_func;
entry = LookupTupleHashEntry_internal(hashtable, slot, isnew, hash);
Assert(entry == NULL || entry->hash == hash);
MemoryContextSwitchTo(oldContext);
@ -480,7 +489,7 @@ TupleHashTableHash_internal(struct tuplehash_hash *tb,
* NB: This function may or may not change the memory context. Caller is
* expected to change it back.
*/
static TupleHashEntry
static inline TupleHashEntry
LookupTupleHashEntry_internal(TupleHashTable hashtable, TupleTableSlot *slot,
bool *isnew, uint32 hash)
{