BothCombinatorRollupHandler.java

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

import org.apache.doris.common.Pair;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.Function;
import org.apache.doris.nereids.trees.expressions.functions.agg.AggregateFunction;
import org.apache.doris.nereids.trees.expressions.functions.agg.RollUpTrait;
import org.apache.doris.nereids.trees.expressions.functions.combinator.Combinator;

import java.util.Map;
import java.util.Objects;

/**
 * Handle the combinator aggregate function roll up, both query and view are combinator
 * Such as query is select c1 sum_merge(sum_state(c2)) from orders group by c1;
 * view is select c1 sum_union(sum_state(c2)) from orders group by c1;
 */
public class BothCombinatorRollupHandler extends AggFunctionRollUpHandler {

    public static BothCombinatorRollupHandler INSTANCE = new BothCombinatorRollupHandler();

    @Override
    public boolean canRollup(AggregateFunction queryAggregateFunction,
            Expression queryAggregateFunctionShuttled,
            Pair<Expression, Expression> mvExprToMvScanExprQueryBasedPair,
            Map<Expression, Expression> mvExprToMvScanExprQueryBasedMap) {
        Expression viewFunction = mvExprToMvScanExprQueryBasedPair.key();
        if (!super.canRollup(queryAggregateFunction, queryAggregateFunctionShuttled,
                mvExprToMvScanExprQueryBasedPair, mvExprToMvScanExprQueryBasedMap)) {
            return false;
        }
        if (queryAggregateFunction instanceof Combinator && viewFunction instanceof Combinator) {
            Combinator queryCombinator = extractLastExpression(queryAggregateFunction, Combinator.class);
            Combinator viewCombinator = extractLastExpression(viewFunction, Combinator.class);
            // construct actual aggregate function in combinator and compare
            return Objects.equals(queryCombinator.getNestedFunction().withChildren(queryCombinator.getArguments()),
                    viewCombinator.getNestedFunction().withChildren(viewCombinator.getArguments()));
        }
        return false;
    }

    @Override
    public Function doRollup(AggregateFunction queryAggregateFunction,
            Expression queryAggregateFunctionShuttled,
            Pair<Expression, Expression> mvExprToMvScanExprQueryBasedPair,
            Map<Expression, Expression> mvExprToMvScanExprQueryBasedMap) {
        Expression rollupParam = mvExprToMvScanExprQueryBasedPair.value();
        return ((RollUpTrait) queryAggregateFunction).constructRollUp(rollupParam);
    }
}