CBOUtils.java

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package org.apache.doris.nereids.rules.exploration;

import org.apache.doris.nereids.trees.expressions.ExprId;
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.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalJoin;
import org.apache.doris.nereids.trees.plans.logical.LogicalProject;
import org.apache.doris.nereids.util.Utils;

import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * Common
 */
public class CBOUtils {
    public static Set<Slot> joinChildConditionSlots(LogicalJoin<? extends Plan, ? extends Plan> join, boolean left) {
        Set<Slot> childSlots = left ? join.left().getOutputSet() : join.right().getOutputSet();
        return join.getConditionSlot().stream()
                .filter(childSlots::contains)
                .collect(Collectors.toSet());
    }

    public static Plan newProjectIfNeeded(Set<ExprId> requiredExprIds, Plan plan) {
        if (requiredExprIds.equals(plan.getOutputExprIdSet())) {
            return plan;
        }
        return newProject(requiredExprIds, plan);
    }

    public static Plan newProject(Set<ExprId> requiredExprIds, Plan plan) {
        List<NamedExpression> projects = plan.getOutput().stream()
                .filter(namedExpr -> requiredExprIds.contains(namedExpr.getExprId()))
                .collect(Collectors.toList());
        return new LogicalProject<>(projects, plan);
    }

    /**
     * Split topJoin Condition to two part according to include bExprIdSet.
     */
    public static Map<Boolean, List<Expression>> splitConjuncts(List<Expression> topConjuncts,
            List<Expression> bottomConjuncts, Set<ExprId> bExprIdSet) {
        // top: (A B)(error) (A C) (B C) (A B C)
        // Split topJoin Condition to two part according to include B.
        Map<Boolean, List<Expression>> splitOn = topConjuncts.stream()
                .collect(Collectors.partitioningBy(topHashOn -> {
                    Set<ExprId> usedExprIds = topHashOn.getInputSlotExprIds();
                    return Utils.isIntersecting(usedExprIds, bExprIdSet);
                }));
        // * don't include B, just include (A C)
        // we add it into newBottomJoin HashConjuncts.
        // * include B, include (A B C) or (A B)
        // we add it into newTopJoin HashConjuncts.
        List<Expression> newTopHashConjuncts = splitOn.get(true);
        newTopHashConjuncts.addAll(bottomConjuncts);

        return splitOn;
    }
}