feat(optimizer): Unwrap casts in comparison expressions #26326
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Reviewer's GuideThis PR implements a new optimizer rule that rewrites comparison expressions by unwrapping safe implicit casts, uses new per-type value ranges to detect out-of-range literals, and wires this feature through configuration, system properties, and supporting utility methods, alongside comprehensive unit and integration tests. Sequence diagram for optimizer rule application in PlanOptimizerssequenceDiagram
participant PlanOptimizers
participant SimplifyRowExpressions
participant UnwrapCastInComparison
participant ExpressionOptimizerManager
PlanOptimizers->>SimplifyRowExpressions: rules()
PlanOptimizers->>UnwrapCastInComparison: rules()
UnwrapCastInComparison->>ExpressionOptimizerManager: optimize(rewrittenExpr, SERIALIZABLE, session)
ExpressionOptimizerManager-->>UnwrapCastInComparison: optimizedExpr
UnwrapCastInComparison-->>PlanOptimizers: rule set
Sequence diagram for UnwrapCastInComparison rule rewriting a comparison expressionsequenceDiagram
participant Optimizer
participant UnwrapCastInComparison
participant Visitor
participant FunctionAndTypeManager
participant FunctionResolution
participant InterpretedFunctionInvoker
Optimizer->>UnwrapCastInComparison: rewrite(expression, session, metadata, exprOptMgr)
UnwrapCastInComparison->>Visitor: rewriteCall(CallExpression, context, treeRewriter)
Visitor->>FunctionResolution: isCastFunction(handle)
Visitor->>FunctionAndTypeManager: lookupCast(CAST, sourceType, targetType)
Visitor->>FunctionAndTypeManager: lookupCast(CAST, targetType, sourceType)
Visitor->>InterpretedFunctionInvoker: invoke(coercion, properties, value)
Visitor-->>UnwrapCastInComparison: rewrittenExpr
UnwrapCastInComparison-->>Optimizer: rewrittenExpr
Class diagram for new and updated Type classes with Range supportclassDiagram
class Type {
+Optional<Range> getRange()
<<interface>>
}
class Type~Range~ {
+Object min
+Object max
+Object getMin()
+Object getMax()
}
Type o-- "1" Range : uses
class BigintType {
+Optional<Range> getRange()
}
class IntegerType {
+Optional<Range> getRange()
}
class SmallintType {
+Optional<Range> getRange()
}
class TinyintType {
+Optional<Range> getRange()
}
class DoubleType {
+Optional<Range> getRange()
}
class RealType {
+Optional<Range> getRange()
}
class AbstractVarcharType {
+Optional<Range> getRange()
}
Type <|.. BigintType
Type <|.. IntegerType
Type <|.. SmallintType
Type <|.. TinyintType
Type <|.. DoubleType
Type <|.. RealType
Type <|.. AbstractVarcharType
Class diagram for UnwrapCastInComparison optimizer ruleclassDiagram
class UnwrapCastInComparison {
+UnwrapCastInComparison(Metadata, ExpressionOptimizerManager)
+PlanRowExpressionRewriter createRewriter(Metadata, ExpressionOptimizerManager)
}
class UnWrapCastInComparisonRewriter {
+static RowExpression rewrite(RowExpression, Session, Metadata, ExpressionOptimizerManager)
}
class Visitor {
+RowExpression rewriteCall(CallExpression, Void, RowExpressionTreeRewriter<Void>)
+RowExpression unwrapCast(RowExpression)
+boolean hasInjectiveImplicitCoercion(Type, Type)
+Object coerce(Object, FunctionHandle)
+int compare(Type, Object, Object)
+RowExpression falseIfNotNull(RowExpression)
+RowExpression trueIfNotNull(RowExpression)
}
UnwrapCastInComparison o-- UnWrapCastInComparisonRewriter : uses
UnWrapCastInComparisonRewriter o-- Visitor : uses
Class diagram for FeaturesConfig and SystemSessionProperties with unwrapCastsclassDiagram
class FeaturesConfig {
-boolean unwrapCasts
+boolean isUnwrapCasts()
+FeaturesConfig setUnwrapCasts(boolean)
}
class SystemSessionProperties {
+static boolean isUnwrapCasts(Session)
}
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Changes adapted from trino/PR#731 Original commit: 4729bc9 e23e317 48336f2 Author: Martin Traverso Co-authored-by: Martin Traverso <[email protected]>
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tdcmeehan
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| public Optional<Range> getRange() | ||
| { | ||
| // The range for double is undefined because NaN is a special value that | ||
| // is *not* in any reasonable definition of a range for this type. | ||
| return Optional.empty(); | ||
| } |
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I actually wonder if this is true. NaN should be treated as the highest value by convention.
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@tdcmeehan Thanks for the review.
You're right that Nan is treated as the largest value in Presto comparisons and ordering. However, returning NaN as the maximum value of a range would not make sense here. In this specific rule, we unwrap a CAST when it's compared to a constant, and the comparison can be further optimized if the constant exceeds the maximum value of the source type. Since NaN is the maximum value when the source type is real or double, no constant can be greater than it, so empty is directly returned in getRange to skip this check.
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Changes adapted from trino/PR#731.
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