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[feature](Nereids): one side eager aggregation #28143

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merged 2 commits into from
Dec 12, 2023
Merged

[feature](Nereids): one side eager aggregation #28143

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83c0f77
[feature](Nereids): one side eager aggregation
jackwener Dec 7, 2023
68412eb
[test](Nereids): add test
jackwener Dec 7, 2023
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6 changes: 6 additions & 0 deletions fe/fe-core/src/main/java/org/apache/doris/nereids/jobs/executor/Rewriter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -91,13 +91,15 @@
import org.apache.doris.nereids.rules.rewrite.PushConjunctsIntoEsScan;
import org.apache.doris.nereids.rules.rewrite.PushConjunctsIntoJdbcScan;
import org.apache.doris.nereids.rules.rewrite.PushDownCountThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownCountThroughJoinOneSide;
import org.apache.doris.nereids.rules.rewrite.PushDownDistinctThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownFilterThroughProject;
import org.apache.doris.nereids.rules.rewrite.PushDownLimit;
import org.apache.doris.nereids.rules.rewrite.PushDownLimitDistinctThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownLimitDistinctThroughUnion;
import org.apache.doris.nereids.rules.rewrite.PushDownMinMaxThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownSumThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownSumThroughJoinOneSide;
import org.apache.doris.nereids.rules.rewrite.PushDownTopNThroughJoin;
import org.apache.doris.nereids.rules.rewrite.PushDownTopNThroughUnion;
import org.apache.doris.nereids.rules.rewrite.PushDownTopNThroughWindow;
Expand Down Expand Up @@ -275,6 +277,10 @@ public class Rewriter extends AbstractBatchJobExecutor {
new PushDownMinMaxThroughJoin(),
new PushDownCountThroughJoin()
),
topDown(
new PushDownSumThroughJoinOneSide(),
new PushDownCountThroughJoinOneSide()
),
custom(RuleType.PUSH_DOWN_DISTINCT_THROUGH_JOIN, PushDownDistinctThroughJoin::new)
),

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3 changes: 3 additions & 0 deletions fe/fe-core/src/main/java/org/apache/doris/nereids/rules/RuleType.java
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Expand Up @@ -167,6 +167,9 @@ public enum RuleType {
PUSH_DOWN_SUM_THROUGH_JOIN(RuleTypeClass.REWRITE),
PUSH_DOWN_COUNT_THROUGH_JOIN(RuleTypeClass.REWRITE),

PUSH_DOWN_SUM_THROUGH_JOIN_ONE_SIDE(RuleTypeClass.REWRITE),
PUSH_DOWN_COUNT_THROUGH_JOIN_ONE_SIDE(RuleTypeClass.REWRITE),

TRANSPOSE_LOGICAL_SEMI_JOIN_LOGICAL_JOIN(RuleTypeClass.REWRITE),
TRANSPOSE_LOGICAL_SEMI_JOIN_LOGICAL_JOIN_PROJECT(RuleTypeClass.REWRITE),
LOGICAL_SEMI_JOIN_COMMUTE(RuleTypeClass.REWRITE),
Expand Down
216 changes: 216 additions & 0 deletions ...src/main/java/org/apache/doris/nereids/rules/rewrite/PushDownCountThroughJoinOneSide.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,216 @@
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.

package org.apache.doris.nereids.rules.rewrite;

import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.expressions.Alias;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.NamedExpression;
import org.apache.doris.nereids.trees.expressions.Slot;
import org.apache.doris.nereids.trees.expressions.functions.agg.AggregateFunction;
import org.apache.doris.nereids.trees.expressions.functions.agg.Count;
import org.apache.doris.nereids.trees.expressions.functions.agg.Sum;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalAggregate;
import org.apache.doris.nereids.trees.plans.logical.LogicalJoin;
import org.apache.doris.nereids.trees.plans.logical.LogicalProject;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
* TODO: distinct | just push one level
* Support Pushdown Count(col).
* Count(col) -> Sum( cnt )
* <p>
* Related paper "Eager aggregation and lazy aggregation".
* <pre>
* aggregate: count(x)
* |
* join
* | \
* | *
* (x)
* ->
* aggregate: Sum( cnt )
* |
* join
* | \
* | *
* aggregate: count(x) as cnt
* </pre>
* Notice: rule can't optimize condition that groupby is empty when Count(*) exists.
*/
public class PushDownCountThroughJoinOneSide implements RewriteRuleFactory {
@Override
public List<Rule> buildRules() {
return ImmutableList.of(
logicalAggregate(innerLogicalJoin())
.when(agg -> agg.child().getOtherJoinConjuncts().isEmpty())
.whenNot(agg -> agg.child().children().stream().anyMatch(p -> p instanceof LogicalAggregate))
.when(agg -> agg.getGroupByExpressions().stream().allMatch(e -> e instanceof Slot))
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why not put "one side only" checking at the pre-checking stage?

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Not a big impact, change it together with the next PR

.when(agg -> {
Set<AggregateFunction> funcs = agg.getAggregateFunctions();
return !funcs.isEmpty() && funcs.stream()
.allMatch(f -> f instanceof Count && !f.isDistinct()
&& (!((Count) f).isCountStar() && f.child(0) instanceof Slot));
})
.thenApply(ctx -> {
Set<Integer> enableNereidsRules = ctx.cascadesContext.getConnectContext()
.getSessionVariable().getEnableNereidsRules();
if (!enableNereidsRules.contains(RuleType.PUSH_DOWN_COUNT_THROUGH_JOIN_ONE_SIDE.type())) {
return null;
}
LogicalAggregate<LogicalJoin<Plan, Plan>> agg = ctx.root;
return pushCount(agg, agg.child(), ImmutableList.of());
})
.toRule(RuleType.PUSH_DOWN_COUNT_THROUGH_JOIN_ONE_SIDE),
logicalAggregate(logicalProject(innerLogicalJoin()))
.when(agg -> agg.child().isAllSlots())
.when(agg -> agg.child().child().getOtherJoinConjuncts().isEmpty())
.whenNot(agg -> agg.child().children().stream().anyMatch(p -> p instanceof LogicalAggregate))
.when(agg -> agg.getGroupByExpressions().stream().allMatch(e -> e instanceof Slot))
.when(agg -> {
Set<AggregateFunction> funcs = agg.getAggregateFunctions();
return !funcs.isEmpty() && funcs.stream()
.allMatch(f -> f instanceof Count && !f.isDistinct()
&& (!((Count) f).isCountStar() && f.child(0) instanceof Slot));
})
.thenApply(ctx -> {
Set<Integer> enableNereidsRules = ctx.cascadesContext.getConnectContext()
.getSessionVariable().getEnableNereidsRules();
if (!enableNereidsRules.contains(RuleType.PUSH_DOWN_COUNT_THROUGH_JOIN_ONE_SIDE.type())) {
return null;
}
LogicalAggregate<LogicalProject<LogicalJoin<Plan, Plan>>> agg = ctx.root;
return pushCount(agg, agg.child().child(), agg.child().getProjects());
})
.toRule(RuleType.PUSH_DOWN_COUNT_THROUGH_JOIN_ONE_SIDE)
);
}

private LogicalAggregate<Plan> pushCount(LogicalAggregate<? extends Plan> agg,
LogicalJoin<Plan, Plan> join, List<NamedExpression> projects) {
List<Slot> leftOutput = join.left().getOutput();
List<Slot> rightOutput = join.right().getOutput();

List<Count> leftCounts = new ArrayList<>();
List<Count> rightCounts = new ArrayList<>();
for (AggregateFunction f : agg.getAggregateFunctions()) {
Count count = (Count) f;
Slot slot = (Slot) count.child(0);
if (leftOutput.contains(slot)) {
leftCounts.add(count);
} else if (rightOutput.contains(slot)) {
rightCounts.add(count);
} else {
throw new IllegalStateException("Slot " + slot + " not found in join output");
}
}

Set<Slot> leftGroupBy = new HashSet<>();
Set<Slot> rightGroupBy = new HashSet<>();
for (Expression e : agg.getGroupByExpressions()) {
Slot slot = (Slot) e;
if (leftOutput.contains(slot)) {
leftGroupBy.add(slot);
} else if (rightOutput.contains(slot)) {
rightGroupBy.add(slot);
} else {
return null;
}
}
join.getHashJoinConjuncts().forEach(e -> e.getInputSlots().forEach(slot -> {
if (leftOutput.contains(slot)) {
leftGroupBy.add(slot);
} else if (rightOutput.contains(slot)) {
rightGroupBy.add(slot);
} else {
throw new IllegalStateException("Slot " + slot + " not found in join output");
}
}));

Plan left = join.left();
Plan right = join.right();

Map<Slot, NamedExpression> leftCntSlotToOutput = new HashMap<>();
Map<Slot, NamedExpression> rightCntSlotToOutput = new HashMap<>();

// left Count agg
if (!leftCounts.isEmpty()) {
Builder<NamedExpression> leftCntAggOutputBuilder = ImmutableList.<NamedExpression>builder()
.addAll(leftGroupBy);
leftCounts.forEach(func -> {
Alias alias = func.alias(func.getName());
leftCntSlotToOutput.put((Slot) func.child(0), alias);
leftCntAggOutputBuilder.add(alias);
});
left = new LogicalAggregate<>(ImmutableList.copyOf(leftGroupBy), leftCntAggOutputBuilder.build(),
join.left());
}

// right Count agg
if (!rightCounts.isEmpty()) {
Builder<NamedExpression> rightCntAggOutputBuilder = ImmutableList.<NamedExpression>builder()
.addAll(rightGroupBy);
rightCounts.forEach(func -> {
Alias alias = func.alias(func.getName());
rightCntSlotToOutput.put((Slot) func.child(0), alias);
rightCntAggOutputBuilder.add(alias);
});

right = new LogicalAggregate<>(ImmutableList.copyOf(rightGroupBy), rightCntAggOutputBuilder.build(),
join.right());
}

Preconditions.checkState(left != join.left() || right != join.right());
Plan newJoin = join.withChildren(left, right);

// top Sum agg
// count(slot) -> sum( count(slot) as cnt )
List<NamedExpression> newOutputExprs = new ArrayList<>();
for (NamedExpression ne : agg.getOutputExpressions()) {
if (ne instanceof Alias && ((Alias) ne).child() instanceof Count) {
Count oldTopCnt = (Count) ((Alias) ne).child();

Slot slot = (Slot) oldTopCnt.child(0);
if (leftCntSlotToOutput.containsKey(slot)) {
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would we do some pre-processing ahead, such as judge which side will push down, and at this point, we just do the transformation without the additional 'if-else'?

Expression expr = new Sum(leftCntSlotToOutput.get(slot).toSlot());
newOutputExprs.add((NamedExpression) ne.withChildren(expr));
} else if (rightCntSlotToOutput.containsKey(slot)) {
Expression expr = new Sum(rightCntSlotToOutput.get(slot).toSlot());
newOutputExprs.add((NamedExpression) ne.withChildren(expr));
} else {
throw new IllegalStateException("Slot " + slot + " not found in join output");
}
} else {
newOutputExprs.add(ne);
}
}
return agg.withAggOutputChild(newOutputExprs, newJoin);
}
}
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