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Revert "TupleHashTable: store additional data along with tuple."

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This reverts commit e0ece2a981 due to
performance regressions.

Reported-by: David Rowley
This commit is contained in:
Jeff Davis
2025-01-13 14:14:07 -08:00
parent af2317652d
commit b4a07f532b
6 changed files with 31 additions and 78 deletions
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57
src/backend/executor/execGrouping.c
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@@ -20,13 +20,6 @@
#include "miscadmin.h"
#include "utils/lsyscache.h"
struct TupleHashEntryData
{
MinimalTuple firstTuple; /* copy of first tuple in this group */
uint32 status; /* hash status */
uint32 hash; /* hash value (cached) */
};
static int TupleHashTableMatch(struct tuplehash_hash *tb, const MinimalTuple tuple1, const MinimalTuple tuple2);
static inline uint32 TupleHashTableHash_internal(struct tuplehash_hash *tb,
const MinimalTuple tuple);
@@ -203,7 +196,6 @@ BuildTupleHashTable(PlanState *parent,
hashtable->tab_collations = collations;
hashtable->tablecxt = tablecxt;
hashtable->tempcxt = tempcxt;
hashtable->additionalsize = additionalsize;
hashtable->tableslot = NULL; /* will be made on first lookup */
hashtable->inputslot = NULL;
hashtable->in_hash_expr = NULL;
@@ -281,15 +273,6 @@ ResetTupleHashTable(TupleHashTable hashtable)
tuplehash_reset(hashtable->hashtab);
}
/*
* Return size of the hash bucket. Useful for estimating memory usage.
*/
size_t
TupleHashEntrySize(void)
{
return sizeof(TupleHashEntryData);
}
/*
* Find or create a hashtable entry for the tuple group containing the
* given tuple. The tuple must be the same type as the hashtable entries.
@@ -356,24 +339,6 @@ TupleHashTableHash(TupleHashTable hashtable, TupleTableSlot *slot)
return hash;
}
MinimalTuple
TupleHashEntryGetTuple(TupleHashEntry entry)
{
return entry->firstTuple;
}
/*
* Get a pointer into the additional space allocated for this entry. The
* amount of space available is the additionalsize specified to
* BuildTupleHashTable(). If additionalsize was specified as zero, no
* additional space is available and this function should not be called.
*/
void *
TupleHashEntryGetAdditional(TupleHashEntry entry)
{
return (char *) entry->firstTuple + MAXALIGN(entry->firstTuple->t_len);
}
/*
* A variant of LookupTupleHashEntry for callers that have already computed
* the hash value.
@@ -512,31 +477,13 @@ LookupTupleHashEntry_internal(TupleHashTable hashtable, TupleTableSlot *slot,
}
else
{
MinimalTuple firstTuple;
size_t totalsize; /* including alignment and additionalsize */
/* created new entry */
*isnew = true;
/* zero caller data */
entry->additional = NULL;
MemoryContextSwitchTo(hashtable->tablecxt);
/* Copy the first tuple into the table context */
firstTuple = ExecCopySlotMinimalTuple(slot);
/*
* Allocate additional space right after the MinimalTuple of size
* additionalsize. The caller can get a pointer to this data with
* TupleHashEntryGetAdditional(), and store arbitrary data there.
*
* This avoids the need to store an extra pointer or allocate an
* additional chunk, which would waste memory.
*/
totalsize = MAXALIGN(firstTuple->t_len) + hashtable->additionalsize;
firstTuple = repalloc(firstTuple, totalsize);
memset((char *) firstTuple + firstTuple->t_len, 0,
totalsize - firstTuple->t_len);
entry->firstTuple = firstTuple;
entry->firstTuple = ExecCopySlotMinimalTuple(slot);
}
}
else