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TupleHashTable: store additional data along with tuple.

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Previously, the caller needed to allocate the memory and the
TupleHashTable would store a pointer to it. That wastes space for the
palloc overhead as well as the size of the pointer itself.

Now, the TupleHashTable relies on the caller to correctly specify the
additionalsize, and allocates that amount of space. The caller can
then request a pointer into that space.

Discussion: https://postgr.es/m/b9cbf0219a9859dc8d240311643ff4362fd9602c.camel@j-davis.com
Reviewed-by: Heikki Linnakangas
This commit is contained in:
Jeff Davis
2025-01-10 17:14:37 -08:00
parent 34c6e65242
commit e0ece2a981
6 changed files with 78 additions and 31 deletions
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20
src/backend/executor/nodeAgg.c
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@ -1713,7 +1713,7 @@ hash_agg_entry_size(int numTrans, Size tupleWidth, Size transitionSpace)
transitionChunkSize = 0;
return
sizeof(TupleHashEntryData) +
TupleHashEntrySize() +
tupleChunkSize +
pergroupChunkSize +
transitionChunkSize;
@ -1954,7 +1954,7 @@ hash_agg_update_metrics(AggState *aggstate, bool from_tape, int npartitions)
if (aggstate->hash_ngroups_current > 0)
{
aggstate->hashentrysize =
sizeof(TupleHashEntryData) +
TupleHashEntrySize() +
(hashkey_mem / (double) aggstate->hash_ngroups_current);
}
}
@ -2055,11 +2055,7 @@ initialize_hash_entry(AggState *aggstate, TupleHashTable hashtable,
if (aggstate->numtrans == 0)
return;
pergroup = (AggStatePerGroup)
MemoryContextAlloc(hashtable->tablecxt,
sizeof(AggStatePerGroupData) * aggstate->numtrans);
entry->additional = pergroup;
pergroup = (AggStatePerGroup) TupleHashEntryGetAdditional(entry);
/*
* Initialize aggregates for new tuple group, lookup_hash_entries()
@ -2123,7 +2119,7 @@ lookup_hash_entries(AggState *aggstate)
{
if (isnew)
initialize_hash_entry(aggstate, hashtable, entry);
pergroup[setno] = entry->additional;
pergroup[setno] = TupleHashEntryGetAdditional(entry);
}
else
{
@ -2681,7 +2677,7 @@ agg_refill_hash_table(AggState *aggstate)
{
if (isnew)
initialize_hash_entry(aggstate, perhash->hashtable, entry);
aggstate->hash_pergroup[batch->setno] = entry->additional;
aggstate->hash_pergroup[batch->setno] = TupleHashEntryGetAdditional(entry);
advance_aggregates(aggstate);
}
else
@ -2773,7 +2769,7 @@ agg_retrieve_hash_table_in_memory(AggState *aggstate)
ExprContext *econtext;
AggStatePerAgg peragg;
AggStatePerGroup pergroup;
TupleHashEntryData *entry;
TupleHashEntry entry;
TupleTableSlot *firstSlot;
TupleTableSlot *result;
AggStatePerHash perhash;
@ -2845,7 +2841,7 @@ agg_retrieve_hash_table_in_memory(AggState *aggstate)
* Transform representative tuple back into one with the right
* columns.
*/
ExecStoreMinimalTuple(entry->firstTuple, hashslot, false);
ExecStoreMinimalTuple(TupleHashEntryGetTuple(entry), hashslot, false);
slot_getallattrs(hashslot);
ExecClearTuple(firstSlot);
@ -2861,7 +2857,7 @@ agg_retrieve_hash_table_in_memory(AggState *aggstate)
}
ExecStoreVirtualTuple(firstSlot);
pergroup = (AggStatePerGroup) entry->additional;
pergroup = (AggStatePerGroup) TupleHashEntryGetAdditional(entry);
/*
* Use the representative input tuple for any references to