Cardinality of filter compared to zero #13867
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| /* | ||
| * Licensed 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 com.facebook.presto.sql.planner.iterative.rule; | ||
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| import static com.facebook.presto.sql.planner.iterative.rule.SimplifyArrayOperationsRewriter.simplifyArrayOperations; | ||
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| public class SimplifyArrayOperations | ||
| extends ExpressionRewriteRuleSet | ||
| { | ||
| public SimplifyArrayOperations() | ||
| { | ||
| super((expression, context) -> simplifyArrayOperations(expression, context.getSession())); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,163 @@ | ||
| /* | ||
| * Licensed 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 com.facebook.presto.sql.planner.iterative.rule; | ||
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| import com.facebook.presto.Session; | ||
| import com.facebook.presto.SystemSessionProperties; | ||
| import com.facebook.presto.sql.tree.Cast; | ||
| import com.facebook.presto.sql.tree.ComparisonExpression; | ||
| import com.facebook.presto.sql.tree.ComparisonExpression.Operator; | ||
| import com.facebook.presto.sql.tree.Expression; | ||
| import com.facebook.presto.sql.tree.ExpressionRewriter; | ||
| import com.facebook.presto.sql.tree.ExpressionTreeRewriter; | ||
| import com.facebook.presto.sql.tree.FunctionCall; | ||
| import com.facebook.presto.sql.tree.LambdaExpression; | ||
| import com.facebook.presto.sql.tree.Literal; | ||
| import com.facebook.presto.sql.tree.LongLiteral; | ||
| import com.facebook.presto.sql.tree.NodeLocation; | ||
| import com.facebook.presto.sql.tree.QualifiedName; | ||
| import com.google.common.collect.ImmutableList; | ||
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| import java.util.Optional; | ||
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| import static com.facebook.presto.sql.tree.ComparisonExpression.Operator.EQUAL; | ||
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| public class SimplifyArrayOperationsRewriter | ||
| { | ||
| private SimplifyArrayOperationsRewriter() {} | ||
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| public static Expression simplifyArrayOperations(Expression expression, Session session) | ||
| { | ||
| if (SystemSessionProperties.isSimplifyArrayOperations(session)) { | ||
| return ExpressionTreeRewriter.rewriteWith(new Visitor(), expression); | ||
| } | ||
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| return expression; | ||
| } | ||
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| private static class Visitor | ||
| extends ExpressionRewriter<Void> | ||
| { | ||
| private static boolean isConstant(Expression expression) | ||
| { | ||
| if (expression instanceof Cast) { | ||
| return isConstant(((Cast) expression).getExpression()); | ||
| } | ||
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| return expression instanceof Literal; | ||
| } | ||
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| private static boolean isZero(Expression expression) | ||
| { | ||
| if (expression instanceof Cast) { | ||
| return isZero(((Cast) expression).getExpression()); | ||
| } | ||
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| return expression instanceof LongLiteral && ((LongLiteral) expression).getValue() == 0; | ||
| } | ||
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| private static boolean isCardinalityOfFilter(Expression expression) | ||
| { | ||
| if (expression instanceof FunctionCall) { | ||
| FunctionCall functionCall = (FunctionCall) expression; | ||
| return functionCall.getName().toString().equals("cardinality") && | ||
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| functionCall.getArguments().size() == 1 && | ||
| functionCall.getArguments().get(0) instanceof FunctionCall && | ||
| ((FunctionCall) (functionCall.getArguments().get(0))).getName().toString().equals("filter"); | ||
| } | ||
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| return false; | ||
| } | ||
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| private static boolean isSimpleComaparison(ComparisonExpression comparisonExpression) | ||
| { | ||
| switch (comparisonExpression.getOperator()) { | ||
| case EQUAL: | ||
| case GREATER_THAN: | ||
| case LESS_THAN: | ||
| case NOT_EQUAL: | ||
| case GREATER_THAN_OR_EQUAL: | ||
| case LESS_THAN_OR_EQUAL: | ||
| return true; | ||
| } | ||
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| return false; | ||
| } | ||
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| private Expression simplifyCardinalityOfFilterComparedToZero( | ||
| NodeLocation location, | ||
| Expression array, | ||
| Operator operator, | ||
| LambdaExpression origLambda) | ||
| { | ||
| // Comparing to zero can be rewrtitten to none_match(= 0) or any_match(> 0) | ||
| return new FunctionCall( | ||
| location, | ||
| QualifiedName.of(operator == EQUAL ? "none_match" : "any_match"), | ||
| ImmutableList.of(array, origLambda)); | ||
| } | ||
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| private Expression simplifyCardinalityOfFilter( | ||
| FunctionCall cardinalityOfFilter, | ||
| Optional<Operator> operator, | ||
| Optional<Expression> rhs, | ||
| Void context, | ||
| ExpressionTreeRewriter<Void> treeRewriter) | ||
| { | ||
| FunctionCall filter = (FunctionCall) cardinalityOfFilter.getArguments().get(0); | ||
| Expression array = treeRewriter.defaultRewrite(filter.getArguments().get(0), context); | ||
| LambdaExpression origLambda = (LambdaExpression) filter.getArguments().get(1); | ||
| boolean isComparison = operator.isPresent() && rhs.isPresent(); | ||
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| if (isComparison && (operator.get() == Operator.EQUAL || operator.get() == Operator.GREATER_THAN) && isZero(rhs.get())) { | ||
| return simplifyCardinalityOfFilterComparedToZero(cardinalityOfFilter.getLocation().orElse(new NodeLocation(0, 0)), array, operator.get(), origLambda); | ||
| } | ||
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| return null; | ||
| } | ||
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| @Override | ||
| public Expression rewriteFunctionCall(FunctionCall functionCall, Void context, ExpressionTreeRewriter<Void> treeRewriter) | ||
| { | ||
| if (isCardinalityOfFilter(functionCall)) { | ||
| return simplifyCardinalityOfFilter(functionCall, Optional.empty(), Optional.empty(), context, treeRewriter); | ||
| } | ||
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| return treeRewriter.defaultRewrite(functionCall, context); | ||
| } | ||
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| @Override | ||
| public Expression rewriteComparisonExpression(ComparisonExpression comparisonExpression, Void context, ExpressionTreeRewriter<Void> treeRewriter) | ||
| { | ||
| Expression left = comparisonExpression.getLeft(); | ||
| Expression right = comparisonExpression.getRight(); | ||
| Operator operator = comparisonExpression.getOperator(); | ||
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| Expression rewritten = null; | ||
| if (isSimpleComaparison(comparisonExpression) && isCardinalityOfFilter(left) && isConstant(right)) { | ||
| rewritten = simplifyCardinalityOfFilter((FunctionCall) left, Optional.of(operator), Optional.of(right), context, treeRewriter); | ||
| } | ||
| else if (isSimpleComaparison(comparisonExpression) && isCardinalityOfFilter(right) && isConstant(left)) { | ||
| // If the left is a literal and right is cardinality, we simply normalize it to reverse the operation. | ||
| rewritten = simplifyCardinalityOfFilter((FunctionCall) left, Optional.of(operator.negate()), Optional.of(right), context, treeRewriter); | ||
| } | ||
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| if (rewritten != null) { | ||
| return rewritten; | ||
| } | ||
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| return treeRewriter.defaultRewrite(comparisonExpression, context); | ||
| } | ||
| } | ||
| } | ||
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cc @highker, @hellium01 : Is this the recommended way to see whether a expression will be evaluated into certain constant?
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Not really; we need to use interpreter and evaluate the expression. The return result of the eval should be a const with
0as its value.