Skip to content

[enhance](Nereids): refactor code in Project #17450

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jackwener merged 1 commit into from
Mar 7, 2023
Merged

[enhance](Nereids): refactor code in Project #17450

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
93 changes: 18 additions & 75 deletions fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/algebra/Project.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,8 +23,6 @@
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.SlotReference;
import org.apache.doris.nereids.trees.expressions.visitor.DefaultExpressionRewriter;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
Expand Down Expand Up @@ -73,16 +71,26 @@ default Map<Slot, Expression> getAliasToProducer() {
* @return project list for merged project
*/
default List<NamedExpression> mergeProjections(Project childProject) {
List<NamedExpression> thisProjectExpressions = getProjects();
List<NamedExpression> childProjectExpressions = childProject.getProjects();
Map<Expression, Expression> bottomAliasMap = childProjectExpressions.stream()
Map<Expression, Alias> replaceMap = childProject.getProjects().stream()
.filter(e -> e instanceof Alias)
.collect(Collectors.toMap(
NamedExpression::toSlot, e -> e)
);
return thisProjectExpressions.stream()
.map(e -> ExpressionReplacer.INSTANCE.replace(e, bottomAliasMap))
.map(NamedExpression.class::cast)
NamedExpression::toSlot,
e -> (Alias) e));
return getProjects().stream()
.map(expr -> {
if (expr instanceof Alias) {
Alias alias = (Alias) expr;
Expression insideExpr = alias.child();
Expression newInsideExpr = insideExpr.rewriteUp(e -> {
Alias getAlias = replaceMap.get(e);
return getAlias == null ? e : getAlias.child();
});
return newInsideExpr == insideExpr ? expr : alias.withChildren(ImmutableList.of(newInsideExpr));
} else {
Alias getAlias = replaceMap.get(expr);
return getAlias == null ? expr : getAlias;
}
})
.collect(ImmutableList.toImmutableList());
}

Expand All @@ -106,71 +114,6 @@ static List<NamedExpression> findProject(
})
.collect(ImmutableList.toImmutableList());
}

/**
* findUsedProject. if not found the slot, then skip it
*/
static <OUTPUT_TYPE extends NamedExpression> List<OUTPUT_TYPE> filterUsedOutputs(
Collection<? extends Slot> slotReferences, List<OUTPUT_TYPE> childOutput) {
Map<ExprId, OUTPUT_TYPE> exprIdToChildOutput = childOutput.stream()
.collect(ImmutableMap.toImmutableMap(p -> p.getExprId(), p -> p));

return slotReferences.stream()
.map(slot -> exprIdToChildOutput.get(slot.getExprId()))
.filter(project -> project != null)
.collect(ImmutableList.toImmutableList());
}

/**
* replace alias
*/
public static class ExpressionReplacer extends DefaultExpressionRewriter<Map<Expression, Expression>> {
public static final ExpressionReplacer INSTANCE = new ExpressionReplacer();

public Expression replace(Expression expr, Map<Expression, Expression> substitutionMap) {
if (expr instanceof SlotReference) {
Slot ref = ((SlotReference) expr).withQualifier(ImmutableList.of());
return substitutionMap.getOrDefault(ref, expr);
}
return visit(expr, substitutionMap);
}

/**
* case 1:
* project(alias(c) as d, alias(x) as y)
* |
* | ===> project(alias(a) as d, alias(b) as y)
* |
* project(slotRef(a) as c, slotRef(b) as x)
* case 2:
* project(slotRef(x.c), slotRef(x.d))
* | ===> project(slotRef(a) as x.c, slotRef(b) as x.d)
* project(slotRef(a) as c, slotRef(b) as d)
* case 3: others
*/
@Override
public Expression visit(Expression expr, Map<Expression, Expression> substitutionMap) {
if (expr instanceof Alias && expr.child(0) instanceof SlotReference) {
// case 1:
Expression c = expr.child(0);
// Alias doesn't contain qualifier
Slot ref = ((SlotReference) c).withQualifier(ImmutableList.of());
if (substitutionMap.containsKey(ref)) {
return expr.withChildren(substitutionMap.get(ref).children());
}
} else if (expr instanceof SlotReference) {
// case 2:
Slot ref = ((SlotReference) expr).withQualifier(ImmutableList.of());
if (substitutionMap.containsKey(ref)) {
Alias res = (Alias) substitutionMap.get(ref);
return res.child();
}
} else if (substitutionMap.containsKey(expr)) {
return substitutionMap.get(expr).child(0);
}
return super.visit(expr, substitutionMap);
}
}
}


3 changes: 2 additions & 1 deletion ...-core/src/test/java/org/apache/doris/nereids/rules/rewrite/logical/MergeProjectsTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,8 @@ public void testMergeConsecutiveProjectsWithAlias() {

@Test
void testAlias() {
// project(a+1 as b) -> project(b+1 as c)
// project(b+1 as c)
// -> project(a+1 as b)
LogicalProject<LogicalOlapScan> bottomProject = new LogicalProject<>(
ImmutableList.of(new Alias(new Add(score.getOutput().get(0), Literal.of(1)), "b")), score);
LogicalProject<LogicalProject<LogicalOlapScan>> topProject = new LogicalProject<>(
Expand Down