Avoid allocating unnecessary zero-sized array.
If there are no aggregates, there is no need to allocate an array of zero AggStatePerGroupData elements.
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b150a76793
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3649133b14
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@ -400,7 +400,8 @@ static int hash_choose_num_partitions(uint64 input_groups,
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double hashentrysize,
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int used_bits,
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int *log2_npartittions);
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static AggStatePerGroup lookup_hash_entry(AggState *aggstate, uint32 hash);
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static AggStatePerGroup lookup_hash_entry(AggState *aggstate, uint32 hash,
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bool *in_hash_table);
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static void lookup_hash_entries(AggState *aggstate);
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static TupleTableSlot *agg_retrieve_direct(AggState *aggstate);
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static void agg_fill_hash_table(AggState *aggstate);
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@ -1968,10 +1969,11 @@ hash_choose_num_partitions(uint64 input_groups, double hashentrysize,
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*
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* If in "spill mode", then only find existing hashtable entries; don't create
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* new ones. If a tuple's group is not already present in the hash table for
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* the current grouping set, return NULL and the caller will spill it to disk.
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* the current grouping set, assign *in_hash_table=false and the caller will
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* spill it to disk.
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*/
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static AggStatePerGroup
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lookup_hash_entry(AggState *aggstate, uint32 hash)
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lookup_hash_entry(AggState *aggstate, uint32 hash, bool *in_hash_table)
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{
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AggStatePerHash perhash = &aggstate->perhash[aggstate->current_set];
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TupleTableSlot *hashslot = perhash->hashslot;
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@ -1987,7 +1989,12 @@ lookup_hash_entry(AggState *aggstate, uint32 hash)
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hash);
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if (entry == NULL)
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{
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*in_hash_table = false;
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return NULL;
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}
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else
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*in_hash_table = true;
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if (isnew)
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{
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@ -1997,9 +2004,14 @@ lookup_hash_entry(AggState *aggstate, uint32 hash)
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aggstate->hash_ngroups_current++;
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hash_agg_check_limits(aggstate);
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/* no need to allocate or initialize per-group state */
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if (aggstate->numtrans == 0)
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return NULL;
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pergroup = (AggStatePerGroup)
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MemoryContextAlloc(perhash->hashtable->tablecxt,
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sizeof(AggStatePerGroupData) * aggstate->numtrans);
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entry->additional = pergroup;
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/*
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@ -2046,14 +2058,15 @@ lookup_hash_entries(AggState *aggstate)
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{
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AggStatePerHash perhash = &aggstate->perhash[setno];
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uint32 hash;
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bool in_hash_table;
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select_current_set(aggstate, setno, true);
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prepare_hash_slot(aggstate);
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hash = TupleHashTableHash(perhash->hashtable, perhash->hashslot);
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pergroup[setno] = lookup_hash_entry(aggstate, hash);
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pergroup[setno] = lookup_hash_entry(aggstate, hash, &in_hash_table);
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/* check to see if we need to spill the tuple for this grouping set */
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if (pergroup[setno] == NULL)
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if (!in_hash_table)
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{
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HashAggSpill *spill = &aggstate->hash_spills[setno];
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TupleTableSlot *slot = aggstate->tmpcontext->ecxt_outertuple;
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@ -2587,6 +2600,7 @@ agg_refill_hash_table(AggState *aggstate)
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TupleTableSlot *slot = aggstate->hash_spill_slot;
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MinimalTuple tuple;
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uint32 hash;
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bool in_hash_table;
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CHECK_FOR_INTERRUPTS();
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@ -2598,9 +2612,10 @@ agg_refill_hash_table(AggState *aggstate)
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aggstate->tmpcontext->ecxt_outertuple = slot;
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prepare_hash_slot(aggstate);
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aggstate->hash_pergroup[batch->setno] = lookup_hash_entry(aggstate, hash);
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aggstate->hash_pergroup[batch->setno] = lookup_hash_entry(
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aggstate, hash, &in_hash_table);
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if (aggstate->hash_pergroup[batch->setno] != NULL)
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if (in_hash_table)
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{
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/* Advance the aggregates (or combine functions) */
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advance_aggregates(aggstate);
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