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Commit5b618e1

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Minor refactor of nodeAgg.c.
 * Separate calculation of hash value from the lookup. * Split build_hash_table() into two functions. * Change lookup_hash_entry() to return AggStatePerGroup. That's all the caller needed, anyway.These changes are to support the upcoming Disk-based Hash Aggregationwork.Discussion:https://postgr.es/m/31f5ab871a3ad5a1a91a7a797651f20e77ac7ce3.camel%40j-davis.com
1 parent8021985 commit5b618e1

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+89
-51
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1 file changed

+89
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‎src/backend/executor/nodeAgg.c

Lines changed: 89 additions & 51 deletions
Original file line numberDiff line numberDiff line change
@@ -263,6 +263,7 @@ static void finalize_partialaggregate(AggState *aggstate,
263263
AggStatePerAggperagg,
264264
AggStatePerGrouppergroupstate,
265265
Datum*resultVal,bool*resultIsNull);
266+
staticvoidprepare_hash_slot(AggState*aggstate);
266267
staticvoidprepare_projection_slot(AggState*aggstate,
267268
TupleTableSlot*slot,
268269
intcurrentSet);
@@ -272,8 +273,9 @@ static void finalize_aggregates(AggState *aggstate,
272273
staticTupleTableSlot*project_aggregates(AggState*aggstate);
273274
staticBitmapset*find_unaggregated_cols(AggState*aggstate);
274275
staticboolfind_unaggregated_cols_walker(Node*node,Bitmapset**colnos);
275-
staticvoidbuild_hash_table(AggState*aggstate);
276-
staticTupleHashEntryData*lookup_hash_entry(AggState*aggstate);
276+
staticvoidbuild_hash_tables(AggState*aggstate);
277+
staticvoidbuild_hash_table(AggState*aggstate,intsetno,longnbuckets);
278+
staticAggStatePerGrouplookup_hash_entry(AggState*aggstate,uint32hash);
277279
staticvoidlookup_hash_entries(AggState*aggstate);
278280
staticTupleTableSlot*agg_retrieve_direct(AggState*aggstate);
279281
staticvoidagg_fill_hash_table(AggState*aggstate);
@@ -1035,6 +1037,32 @@ finalize_partialaggregate(AggState *aggstate,
10351037
MemoryContextSwitchTo(oldContext);
10361038
}
10371039

1040+
/*
1041+
* Extract the attributes that make up the grouping key into the
1042+
* hashslot. This is necessary to compute the hash or perform a lookup.
1043+
*/
1044+
staticvoid
1045+
prepare_hash_slot(AggState*aggstate)
1046+
{
1047+
TupleTableSlot*inputslot=aggstate->tmpcontext->ecxt_outertuple;
1048+
AggStatePerHashperhash=&aggstate->perhash[aggstate->current_set];
1049+
TupleTableSlot*hashslot=perhash->hashslot;
1050+
inti;
1051+
1052+
/* transfer just the needed columns into hashslot */
1053+
slot_getsomeattrs(inputslot,perhash->largestGrpColIdx);
1054+
ExecClearTuple(hashslot);
1055+
1056+
for (i=0;i<perhash->numhashGrpCols;i++)
1057+
{
1058+
intvarNumber=perhash->hashGrpColIdxInput[i]-1;
1059+
1060+
hashslot->tts_values[i]=inputslot->tts_values[varNumber];
1061+
hashslot->tts_isnull[i]=inputslot->tts_isnull[varNumber];
1062+
}
1063+
ExecStoreVirtualTuple(hashslot);
1064+
}
1065+
10381066
/*
10391067
* Prepare to finalize and project based on the specified representative tuple
10401068
* slot and grouping set.
@@ -1249,41 +1277,59 @@ find_unaggregated_cols_walker(Node *node, Bitmapset **colnos)
12491277
* they are all reset at the same time).
12501278
*/
12511279
staticvoid
1252-
build_hash_table(AggState*aggstate)
1280+
build_hash_tables(AggState*aggstate)
12531281
{
1254-
MemoryContexttmpmem=aggstate->tmpcontext->ecxt_per_tuple_memory;
1255-
Sizeadditionalsize;
1256-
inti;
1282+
intsetno;
12571283

1258-
Assert(aggstate->aggstrategy==AGG_HASHED||aggstate->aggstrategy==AGG_MIXED);
1259-
1260-
additionalsize=aggstate->numtrans*sizeof(AggStatePerGroupData);
1261-
1262-
for (i=0;i<aggstate->num_hashes;++i)
1284+
for (setno=0;setno<aggstate->num_hashes;++setno)
12631285
{
1264-
AggStatePerHashperhash=&aggstate->perhash[i];
1286+
AggStatePerHashperhash=&aggstate->perhash[setno];
12651287

12661288
Assert(perhash->aggnode->numGroups>0);
12671289

1268-
if (perhash->hashtable)
1269-
ResetTupleHashTable(perhash->hashtable);
1270-
else
1271-
perhash->hashtable=BuildTupleHashTableExt(&aggstate->ss.ps,
1272-
perhash->hashslot->tts_tupleDescriptor,
1273-
perhash->numCols,
1274-
perhash->hashGrpColIdxHash,
1275-
perhash->eqfuncoids,
1276-
perhash->hashfunctions,
1277-
perhash->aggnode->grpCollations,
1278-
perhash->aggnode->numGroups,
1279-
additionalsize,
1280-
aggstate->ss.ps.state->es_query_cxt,
1281-
aggstate->hashcontext->ecxt_per_tuple_memory,
1282-
tmpmem,
1283-
DO_AGGSPLIT_SKIPFINAL(aggstate->aggsplit));
1290+
build_hash_table(aggstate,setno,perhash->aggnode->numGroups);
12841291
}
12851292
}
12861293

1294+
/*
1295+
* Build a single hashtable for this grouping set.
1296+
*/
1297+
staticvoid
1298+
build_hash_table(AggState*aggstate,intsetno,longnbuckets)
1299+
{
1300+
AggStatePerHashperhash=&aggstate->perhash[setno];
1301+
MemoryContextmetacxt=aggstate->ss.ps.state->es_query_cxt;
1302+
MemoryContexthashcxt=aggstate->hashcontext->ecxt_per_tuple_memory;
1303+
MemoryContexttmpcxt=aggstate->tmpcontext->ecxt_per_tuple_memory;
1304+
Sizeadditionalsize;
1305+
1306+
Assert(aggstate->aggstrategy==AGG_HASHED||
1307+
aggstate->aggstrategy==AGG_MIXED);
1308+
1309+
/*
1310+
* Used to make sure initial hash table allocation does not exceed
1311+
* work_mem. Note that the estimate does not include space for
1312+
* pass-by-reference transition data values, nor for the representative
1313+
* tuple of each group.
1314+
*/
1315+
additionalsize=aggstate->numtrans*sizeof(AggStatePerGroupData);
1316+
1317+
perhash->hashtable=BuildTupleHashTableExt(
1318+
&aggstate->ss.ps,
1319+
perhash->hashslot->tts_tupleDescriptor,
1320+
perhash->numCols,
1321+
perhash->hashGrpColIdxHash,
1322+
perhash->eqfuncoids,
1323+
perhash->hashfunctions,
1324+
perhash->aggnode->grpCollations,
1325+
nbuckets,
1326+
additionalsize,
1327+
metacxt,
1328+
hashcxt,
1329+
tmpcxt,
1330+
DO_AGGSPLIT_SKIPFINAL(aggstate->aggsplit));
1331+
}
1332+
12871333
/*
12881334
* Compute columns that actually need to be stored in hashtable entries. The
12891335
* incoming tuples from the child plan node will contain grouping columns,
@@ -1441,33 +1487,20 @@ hash_agg_entry_size(int numAggs, Size tupleWidth, Size transitionSpace)
14411487
* set (which the caller must have selected - note that initialize_aggregate
14421488
* depends on this).
14431489
*
1444-
* When called, CurrentMemoryContext should be the per-query context.
1490+
* When called, CurrentMemoryContext should be the per-query context. The
1491+
* already-calculated hash value for the tuple must be specified.
14451492
*/
1446-
staticTupleHashEntryData*
1447-
lookup_hash_entry(AggState*aggstate)
1493+
staticAggStatePerGroup
1494+
lookup_hash_entry(AggState*aggstate,uint32hash)
14481495
{
1449-
TupleTableSlot*inputslot=aggstate->tmpcontext->ecxt_outertuple;
14501496
AggStatePerHashperhash=&aggstate->perhash[aggstate->current_set];
14511497
TupleTableSlot*hashslot=perhash->hashslot;
14521498
TupleHashEntryData*entry;
14531499
boolisnew;
1454-
inti;
1455-
1456-
/* transfer just the needed columns into hashslot */
1457-
slot_getsomeattrs(inputslot,perhash->largestGrpColIdx);
1458-
ExecClearTuple(hashslot);
1459-
1460-
for (i=0;i<perhash->numhashGrpCols;i++)
1461-
{
1462-
intvarNumber=perhash->hashGrpColIdxInput[i]-1;
1463-
1464-
hashslot->tts_values[i]=inputslot->tts_values[varNumber];
1465-
hashslot->tts_isnull[i]=inputslot->tts_isnull[varNumber];
1466-
}
1467-
ExecStoreVirtualTuple(hashslot);
14681500

14691501
/* find or create the hashtable entry using the filtered tuple */
1470-
entry=LookupTupleHashEntry(perhash->hashtable,hashslot,&isnew);
1502+
entry=LookupTupleHashEntryHash(perhash->hashtable,hashslot,&isnew,
1503+
hash);
14711504

14721505
if (isnew)
14731506
{
@@ -1492,7 +1525,7 @@ lookup_hash_entry(AggState *aggstate)
14921525
}
14931526
}
14941527

1495-
returnentry;
1528+
returnentry->additional;
14961529
}
14971530

14981531
/*
@@ -1510,8 +1543,13 @@ lookup_hash_entries(AggState *aggstate)
15101543

15111544
for (setno=0;setno<numHashes;setno++)
15121545
{
1546+
AggStatePerHashperhash=&aggstate->perhash[setno];
1547+
uint32hash;
1548+
15131549
select_current_set(aggstate,setno, true);
1514-
pergroup[setno]=lookup_hash_entry(aggstate)->additional;
1550+
prepare_hash_slot(aggstate);
1551+
hash=TupleHashTableHash(perhash->hashtable,perhash->hashslot);
1552+
pergroup[setno]=lookup_hash_entry(aggstate,hash);
15151553
}
15161554
}
15171555

@@ -2478,7 +2516,7 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
24782516
aggstate->hash_pergroup=pergroups;
24792517

24802518
find_hash_columns(aggstate);
2481-
build_hash_table(aggstate);
2519+
build_hash_tables(aggstate);
24822520
aggstate->table_filled= false;
24832521
}
24842522

@@ -3498,7 +3536,7 @@ ExecReScanAgg(AggState *node)
34983536
{
34993537
ReScanExprContext(node->hashcontext);
35003538
/* Rebuild an empty hash table */
3501-
build_hash_table(node);
3539+
build_hash_tables(node);
35023540
node->table_filled= false;
35033541
/* iterator will be reset when the table is filled */
35043542
}

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