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Merged
merged 1 commit into from
Nov 22, 2024
Merged

Show stats in EXPLAIN/EXPLAIN ANALYZE with intermediate aggregation #24231

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7 changes: 4 additions & 3 deletions core/trino-main/src/main/java/io/trino/cost/AggregationStatsRule.java
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Original file line number Diff line number Diff line change
Expand Up @@ -49,13 +49,13 @@ public Pattern<AggregationNode> getPattern()
@Override
protected Optional<PlanNodeStatsEstimate> doCalculate(AggregationNode node, Context context)
{
if (node.getGroupingSetCount() != 1 || node.getStep() == INTERMEDIATE) {
if (node.getGroupingSetCount() != 1) {
return Optional.empty();
}

PlanNodeStatsEstimate estimate;

if (node.getStep() == PARTIAL) {
if (node.getStep() == PARTIAL || node.getStep() == INTERMEDIATE) {
estimate = partialGroupBy(context.statsProvider().getStats(node.getSource()),
node.getGroupingKeys(),
node.getAggregations());
Expand Down Expand Up @@ -101,7 +101,8 @@ public static double getRowsCount(PlanNodeStatsEstimate sourceStats, Collection<

private static PlanNodeStatsEstimate partialGroupBy(PlanNodeStatsEstimate sourceStats, Collection<Symbol> groupBySymbols, Map<Symbol, Aggregation> aggregations)
{
// Pessimistic assumption of no reduction from PARTIAL aggregation, forwarding of the source statistics. This makes the CBO estimates in the EXPLAIN plan output easier to understand,
// Pessimistic assumption of no reduction from PARTIAL and INTERMEDIATE aggregation, forwarding of the source statistics.
// This makes the CBO estimates in the EXPLAIN plan output easier to understand,
// even though partial aggregations are added after the CBO rules have been run.
PlanNodeStatsEstimate.Builder result = PlanNodeStatsEstimate.builder();
result.setOutputRowCount(sourceStats.getOutputRowCount());
Expand Down
42 changes: 42 additions & 0 deletions core/trino-main/src/test/java/io/trino/cost/TestAggregationStatsRule.java
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Original file line number Diff line number Diff line change
Expand Up @@ -185,4 +185,46 @@ public void testAggregationWithMoreGroupingSets()
.build())
.check(PlanNodeStatsAssertion::outputRowsCountUnknown);
}

@Test
void testAggregationStep()
{
testAggregationStep(AggregationNode.Step.PARTIAL);
testAggregationStep(AggregationNode.Step.INTERMEDIATE);
testAggregationStep(AggregationNode.Step.FINAL);
testAggregationStep(AggregationNode.Step.SINGLE);
}

void testAggregationStep(AggregationNode.Step step)
{
tester().assertStatsFor(pb -> pb
.aggregation(ab -> ab
.step(step)
.addAggregation(pb.symbol("sum", BIGINT), aggregation("sum", ImmutableList.of(new Reference(BIGINT, "x"))), ImmutableList.of(BIGINT))
.singleGroupingSet(pb.symbol("y", BIGINT), pb.symbol("z", BIGINT))
.source(pb.values(pb.symbol("y", BIGINT), pb.symbol("z", BIGINT)))))
.withSourceStats(PlanNodeStatsEstimate.builder()
.setOutputRowCount(100)
.addSymbolStatistics(new Symbol(BIGINT, "y"), SymbolStatsEstimate.builder()
.setLowValue(1)
.setHighValue(10)
.setDistinctValuesCount(5)
.setNullsFraction(0.3)
.build())
.addSymbolStatistics(new Symbol(BIGINT, "z"), SymbolStatsEstimate.builder()
.setLowValue(0)
.setHighValue(3)
.setDistinctValuesCount(3)
.setNullsFraction(0)
.build())
.build())
.check(check -> {
if (step.isOutputPartial()) {
check.outputRowsCount(100);
}
else {
check.outputRowsCount(18);
}
});
}
}
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