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[opt](Nereids) Optimize findValidItems method to handle circular dependencies #36839

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Merged
keanji-x merged 1 commit into from
Jun 26, 2024
Merged

[opt](Nereids) Optimize findValidItems method to handle circular dependencies #36839

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25 changes: 20 additions & 5 deletions fe/fe-core/src/main/java/org/apache/doris/nereids/properties/FuncDeps.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;

/**
* Function dependence items.
Expand Down Expand Up @@ -96,11 +97,25 @@ private void dfs(Set<Slot> parent, Set<Set<Slot>> visited, Set<FuncDepsItem> cir
}
}

// find item that not in a circle
private Set<FuncDepsItem> findValidItems() {
// Find items that are not part of a circular dependency.
// To keep the slots in requireOutputs, we need to always keep the edges that start with output slots.
// Note: We reduce the last edge in a circular dependency,
// so we need to traverse from parents that contain the required output slots.
private Set<FuncDepsItem> findValidItems(Set<Slot> requireOutputs) {
Set<FuncDepsItem> circleItem = new HashSet<>();
Set<Set<Slot>> visited = new HashSet<>();
for (Set<Slot> parent : edges.keySet()) {
Set<Set<Slot>> parentInOutput = edges.keySet().stream()
.filter(requireOutputs::containsAll)
.collect(Collectors.toSet());
for (Set<Slot> parent : parentInOutput) {
if (!visited.contains(parent)) {
dfs(parent, visited, circleItem);
}
}
Set<Set<Slot>> otherParent = edges.keySet().stream()
.filter(parent -> !parentInOutput.contains(parent))
.collect(Collectors.toSet());
for (Set<Slot> parent : otherParent) {
if (!visited.contains(parent)) {
dfs(parent, visited, circleItem);
}
Expand All @@ -126,10 +141,10 @@ private Set<FuncDepsItem> findValidItems() {
* @param slots the initial set of slot sets to be reduced
* @return the minimal set of slot sets after applying all possible reductions
*/
public Set<Set<Slot>> eliminateDeps(Set<Set<Slot>> slots) {
public Set<Set<Slot>> eliminateDeps(Set<Set<Slot>> slots, Set<Slot> requireOutputs) {
Set<Set<Slot>> minSlotSet = Sets.newHashSet(slots);
Set<Set<Slot>> eliminatedSlots = new HashSet<>();
Set<FuncDepsItem> validItems = findValidItems();
Set<FuncDepsItem> validItems = findValidItems(requireOutputs);
for (FuncDepsItem funcDepsItem : validItems) {
if (minSlotSet.contains(funcDepsItem.dependencies)
&& minSlotSet.contains(funcDepsItem.determinants)) {
Expand Down
2 changes: 1 addition & 1 deletion fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/EliminateGroupByKey.java
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Original file line number Diff line number Diff line change
Expand Up @@ -91,7 +91,7 @@ LogicalAggregate<Plan> eliminateGroupByKey(LogicalAggregate<? extends Plan> agg,
return null;
}

Set<Set<Slot>> minGroupBySlots = funcDeps.eliminateDeps(new HashSet<>(groupBySlots.values()));
Set<Set<Slot>> minGroupBySlots = funcDeps.eliminateDeps(new HashSet<>(groupBySlots.values()), requireOutput);
Set<Expression> removeExpression = new HashSet<>();
for (Entry<Expression, Set<Slot>> entry : groupBySlots.entrySet()) {
if (!minGroupBySlots.contains(entry.getValue())
Expand Down
13 changes: 7 additions & 6 deletions fe/fe-core/src/test/java/org/apache/doris/nereids/properties/FuncDepsTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
import org.apache.doris.nereids.trees.expressions.SlotReference;
import org.apache.doris.nereids.types.IntegerType;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
Expand All @@ -43,7 +44,7 @@ void testOneEliminate() {
Set<Set<Slot>> slotSet = Sets.newHashSet(set1, set2, set3, set4);
FuncDeps funcDeps = new FuncDeps();
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s2));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
expected.add(set3);
Expand All @@ -58,7 +59,7 @@ void testChainEliminate() {
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s2));
funcDeps.addFuncItems(Sets.newHashSet(s2), Sets.newHashSet(s3));
funcDeps.addFuncItems(Sets.newHashSet(s3), Sets.newHashSet(s4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
Assertions.assertEquals(expected, slots);
Expand All @@ -71,7 +72,7 @@ void testTreeEliminate() {
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s2));
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s3));
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
Assertions.assertEquals(expected, slots);
Expand All @@ -83,7 +84,7 @@ void testCircleEliminate1() {
FuncDeps funcDeps = new FuncDeps();
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s2));
funcDeps.addFuncItems(Sets.newHashSet(s2), Sets.newHashSet(s1));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
expected.add(set3);
Expand All @@ -99,7 +100,7 @@ void testCircleEliminate2() {
funcDeps.addFuncItems(Sets.newHashSet(s2), Sets.newHashSet(s3));
funcDeps.addFuncItems(Sets.newHashSet(s3), Sets.newHashSet(s4));
funcDeps.addFuncItems(Sets.newHashSet(s4), Sets.newHashSet(s1));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
Assertions.assertEquals(expected, slots);
Expand All @@ -112,7 +113,7 @@ void testGraphEliminate1() {
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s2));
funcDeps.addFuncItems(Sets.newHashSet(s1), Sets.newHashSet(s3));
funcDeps.addFuncItems(Sets.newHashSet(s3), Sets.newHashSet(s4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(slotSet, ImmutableSet.of());
Set<Set<Slot>> expected = new HashSet<>();
expected.add(set1);
Assertions.assertEquals(expected, slots);
Expand Down
21 changes: 15 additions & 6 deletions fe/fe-core/src/test/java/org/apache/doris/nereids/rules/rewrite/EliminateGroupByKeyTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,7 @@ void testEliminateChain() {
funcDeps.addFuncItems(set1, set2);
funcDeps.addFuncItems(set2, set3);
funcDeps.addFuncItems(set3, set4);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4), ImmutableSet.of());
Assertions.assertEquals(1, slots.size());
Assertions.assertEquals(set1, slots.iterator().next());
}
Expand All @@ -78,7 +78,7 @@ void testEliminateCircle() {
funcDeps.addFuncItems(set2, set3);
funcDeps.addFuncItems(set3, set4);
funcDeps.addFuncItems(set4, set1);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4), ImmutableSet.of());
Assertions.assertEquals(1, slots.size());
Assertions.assertEquals(set1, slots.iterator().next());
}
Expand All @@ -89,7 +89,7 @@ void testEliminateTree() {
funcDeps.addFuncItems(set1, set2);
funcDeps.addFuncItems(set1, set3);
funcDeps.addFuncItems(set1, set4);
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4));
Set<Set<Slot>> slots = funcDeps.eliminateDeps(ImmutableSet.of(set1, set2, set3, set4), ImmutableSet.of());
Assertions.assertEquals(1, slots.size());
Assertions.assertEquals(set1, slots.iterator().next());
}
Expand Down Expand Up @@ -163,11 +163,20 @@ void testEliminateByPk() throws Exception {
@Test
void testEliminateByEqual() {
PlanChecker.from(connectContext)
.analyze("select count(t1.name) from t1 as t1 join t1 as t2 on t1.name = t2.name group by t1.name, t2.name")
.analyze("select t1.name from t1 as t1 join t1 as t2 on t1.name = t2.name group by t1.name, t2.name")
.rewrite()
.printlnTree()
.matches(logicalAggregate().when(agg ->
agg.getGroupByExpressions().size() == 1 && agg.getGroupByExpressions().get(0).toSql().equals("name")));
}
agg.getGroupByExpressions().size() == 1
&& agg.getGroupByExpressions().get(0).toSql().equals("name")));

PlanChecker.from(connectContext)
.analyze("select t2.name from t1 as t1 join t1 as t2 "
+ "on t1.name = t2.name group by t1.name, t2.name")
.rewrite()
.printlnTree()
.matches(logicalAggregate().when(agg ->
agg.getGroupByExpressions().size() == 1
&& agg.getGroupByExpressions().get(0).toSql().equals("name")));
}
}