org.apache.asterix.optimizer.rules.am.IAccessMethod Maven / Gradle / Ivy

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 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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
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 *   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.asterix.optimizer.rules.am;

import java.util.List;

import org.apache.commons.lang3.mutable.Mutable;

import org.apache.asterix.metadata.entities.Index;
import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;

/**
 * Interface that an access method should implement to work with the rewrite
 * rules to apply it for join and/or selection queries. This interface provides
 * methods for analyzing a select/join condition, and for rewriting the plan
 * with a given index.
 */
public interface IAccessMethod {

    /**
     * @return A list of function identifiers that are optimizable by this
     *         access method.
     */
    public List getOptimizableFunctions();

    /**
     * Analyzes the arguments of a given optimizable funcExpr to see if this
     * access method is applicable (e.g., one arg is a constant and one is a
     * var). We assume that the funcExpr has already been determined to be
     * optimizable by this access method based on its function identifier. If
     * funcExpr has been found to be optimizable, this method adds an
     * OptimizableFunction to analysisCtx.matchedFuncExprs for further analysis.
     *
     * @return true if funcExpr is optimizable by this access method, false
     *         otherwise
     */
    public boolean analyzeFuncExprArgs(AbstractFunctionCallExpression funcExpr,
            List assignsAndUnnests, AccessMethodAnalysisContext analysisCtx);

    /**
     * Indicates whether all index expressions must be matched in order for this
     * index to be applicable.
     *
     * @return boolean
     */
    public boolean matchAllIndexExprs();

    /**
     * Indicates whether this index is applicable if only a prefix of the index
     * expressions are matched.
     *
     * @return boolean
     */
    public boolean matchPrefixIndexExprs();

    /**
     * Applies the plan transformation to use chosenIndex to optimize a selection query.
     */
    public boolean applySelectPlanTransformation(Mutable selectRef,
            OptimizableOperatorSubTree subTree, Index chosenIndex, AccessMethodAnalysisContext analysisCtx,
            IOptimizationContext context) throws AlgebricksException;

    /**
     * Applies the plan transformation to use chosenIndex to optimize a join query.
     * In the case of a LeftOuterJoin, there may or may not be a needed groupby operation
     * If there is, we will need to include it in the transformation
     */
    public boolean applyJoinPlanTransformation(Mutable joinRef,
            OptimizableOperatorSubTree leftSubTree, OptimizableOperatorSubTree rightSubTree, Index chosenIndex,
            AccessMethodAnalysisContext analysisCtx, IOptimizationContext context, boolean isLeftOuterJoin,
            boolean hasGroupBy) throws AlgebricksException;

    /**
     * Analyzes expr to see whether it is optimizable by the given concrete index.
     * 
     * @throws AlgebricksException
     */
    public boolean exprIsOptimizable(Index index, IOptimizableFuncExpr optFuncExpr) throws AlgebricksException;
}