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feat(primproc,aggregegation)!: Changes for ROLLUP with single-phase aggregation (#3025)

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The fix is simple: enable subtotals in single-phase aggregation and
disable parallel processing when there are subtotals and aggregation is
single-phase.
This commit is contained in:
Sergey Zefirov
2023-11-28 17:33:02 +03:00
committed by GitHub
parent 9a84aa8d99
commit 8632c85ecf
5 changed files with 29 additions and 4 deletions
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17
dbcon/joblist/tupleaggregatestep.cpp
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@ -1503,7 +1503,7 @@ void TupleAggregateStep::prep1PhaseAggregate(JobInfo& jobInfo, vector<RowGroup>&
RowGroup aggRG(oidsAgg.size(), posAgg, oidsAgg, keysAgg, typeAgg, csNumAgg, scaleAgg, precisionAgg,
jobInfo.stringTableThreshold);
SP_ROWAGG_UM_t rowAgg(new RowAggregationUM(groupBy, functionVec, jobInfo.rm, jobInfo.umMemLimit, false));
SP_ROWAGG_UM_t rowAgg(new RowAggregationUM(groupBy, functionVec, jobInfo.rm, jobInfo.umMemLimit, jobInfo.hasRollup));
rowAgg->timeZone(jobInfo.timeZone);
rowgroups.push_back(aggRG);
aggregators.push_back(rowAgg);
@ -5443,7 +5443,6 @@ void TupleAggregateStep::threadedAggregateRowGroups(uint32_t threadID)
for (uint32_t i = 0; i < fNumOfBuckets; i++)
{
fAggregators[i].reset(fAggregator->clone());
fAggregators[i]->clearRollup();
fAggregators[i]->setInputOutput(fRowGroupIn, &fRowGroupOuts[i]);
}
}
@ -5497,7 +5496,19 @@ void TupleAggregateStep::threadedAggregateRowGroups(uint32_t threadID)
// The key is the groupby columns, which are the leading columns.
// TBD This approach could potential
// put all values in on bucket.
uint64_t hash = rowgroup::hashRow(rowIn, hashLens[0] - 1);
// The fAggregator->hasRollup() is true when we perform one-phase
// aggregation and also are doing subtotals' computations.
// Subtotals produce new keys whose hash values may not be in
// the processing bucket. Consider case for key tuples (1,2) and (1,3).
// Their subtotals's keys will be (1, NULL) and (1, NULL)
// but they will be left in their processing buckets and never
// gets aggregated properly.
// Due to this, we put all rows into the same bucket 0 when perfoming
// single-phase aggregation with subtotals.
// For all other cases (single-phase without subtotals and two-phase
// aggregation with and without subtotals) fAggregator->hasRollup() is false.
// In these cases we have full parallel processing as expected.
uint64_t hash = fAggregator->hasRollup() ? 0 : rowgroup::hashRow(rowIn, hashLens[0] - 1);
int bucketID = hash % fNumOfBuckets;
rowBucketVecs[bucketID][0].emplace_back(rowIn.getPointer(), hash);
rowIn.nextRow();

9
mysql-test/columnstore/basic/r/mcs84_rollup.result
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@ -56,6 +56,15 @@ Paraguay non-fiction 17790
Senegal NULL 171762
Senegal fiction 27881
Senegal non-fiction 143881
SELECT country, genre, SUM(sales) FROM (SELECT country, genre, sales FROM booksales) t1 GROUP BY country, genre WITH ROLLUP;
country genre SUM(sales)
NULL NULL 354462
Paraguay NULL 182700
Paraguay fiction 164910
Paraguay non-fiction 17790
Senegal NULL 171762
Senegal fiction 27881
Senegal non-fiction 143881
CREATE TABLE three_cols ( key1 INTEGER, key2 INTEGER, value DECIMAL(38)) ENGINE=COLUMNSTORE;
INSERT INTO three_cols(key1, key2, value) VALUES
(NULL, NULL, NULL)

3
mysql-test/columnstore/basic/t/mcs84_rollup.test
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@ -42,6 +42,9 @@ SELECT year, SUM(sales) FROM booksales GROUP BY year WITH ROLLUP;
--sorted_result
SELECT country, genre, SUM(sales) FROM booksales GROUP BY country, genre WITH ROLLUP;
--sorted_result
SELECT country, genre, SUM(sales) FROM (SELECT country, genre, sales FROM booksales) t1 GROUP BY country, genre WITH ROLLUP;
CREATE TABLE three_cols ( key1 INTEGER, key2 INTEGER, value DECIMAL(38)) ENGINE=COLUMNSTORE;
INSERT INTO three_cols(key1, key2, value) VALUES

2
utils/common/string_prefixes.cpp
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@ -42,7 +42,7 @@ int64_t encodeStringPrefix(const uint8_t* str, size_t len, datatypes::Charset& c
int64_t encodeStringPrefix_check_null(const uint8_t* str, size_t len, datatypes::Charset& cset)
{
if (len < 1 && str == nullptr)
if (len < 1)
{
return joblist::UBIGINTNULL;
}

2
utils/rowgroup/rowaggregation.h
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@ -425,6 +425,8 @@ class RowAggregation : public messageqcpp::Serializeable
void clearRollup() { fRollupFlag = false; }
bool hasRollup() const { return fRollupFlag; }
/** @brief Define content of data to be joined
*
* This method must be call after setInputOutput() for PM hashjoin case.