LogicalDeferMaterializeTopNToPhysicalDeferMaterializeTopN.java

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

import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.SortPhase;
import org.apache.doris.nereids.trees.plans.logical.LogicalDeferMaterializeTopN;
import org.apache.doris.nereids.trees.plans.physical.PhysicalDeferMaterializeTopN;
import org.apache.doris.nereids.trees.plans.physical.PhysicalTopN;

import java.util.Optional;

/**
 * implement defer materialize top n from logical to physical
 */
public class LogicalDeferMaterializeTopNToPhysicalDeferMaterializeTopN extends OneImplementationRuleFactory {
    @Override
    public Rule build() {
        return logicalDeferMaterializeTopN().thenApply(ctx -> {
            LogicalDeferMaterializeTopN<? extends Plan> topN = ctx.root;
            PhysicalTopN<? extends Plan> physicalTopN = (PhysicalTopN<? extends Plan>) new LogicalTopNToPhysicalTopN()
                    .build()
                    .transform(topN.getLogicalTopN(), ctx.cascadesContext)
                    .get(0);
            if (physicalTopN.getSortPhase() == SortPhase.MERGE_SORT) {
                return wrap(physicalTopN, topN, wrap((PhysicalTopN<? extends Plan>) physicalTopN.child(), topN,
                        ((PhysicalTopN<?>) physicalTopN.child()).child()));
            } else {
                return wrap(physicalTopN, topN, physicalTopN.child());
            }

        }).toRule(RuleType.LOGICAL_DEFER_MATERIALIZE_TOP_N_TO_PHYSICAL_DEFER_MATERIALIZE_TOP_N_RULE);
    }

    private PhysicalDeferMaterializeTopN<? extends Plan> wrap(PhysicalTopN<? extends Plan> physicalTopN,
            LogicalDeferMaterializeTopN<? extends Plan> logicalWrapped, Plan child) {
        return new PhysicalDeferMaterializeTopN<>(physicalTopN,
                logicalWrapped.getDeferMaterializeSlotIds(), logicalWrapped.getColumnIdSlot(),
                Optional.empty(), logicalWrapped.getLogicalProperties(), child);
    }
}