MaterializedViewTopNScanRule.java

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

import org.apache.doris.nereids.CascadesContext;
import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.rules.exploration.mv.StructInfo.PlanCheckContext;
import org.apache.doris.nereids.rules.exploration.mv.mapping.SlotMapping;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalCatalogRelation;
import org.apache.doris.nereids.trees.plans.logical.LogicalFilter;
import org.apache.doris.nereids.trees.plans.logical.LogicalProject;
import org.apache.doris.nereids.trees.plans.logical.LogicalTopN;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;

import java.util.List;
import java.util.Optional;

/**
 * MaterializedViewLimitScanRule
 */
public class MaterializedViewTopNScanRule extends AbstractMaterializedViewScanRule
        implements AbstractMaterializedViewLimitOrTopNRule {

    public static final MaterializedViewTopNScanRule INSTANCE = new MaterializedViewTopNScanRule();

    @Override
    protected Plan rewriteQueryByView(MatchMode matchMode, StructInfo queryStructInfo, StructInfo viewStructInfo,
            SlotMapping viewToQuerySlotMapping, Plan tempRewritedPlan, MaterializationContext materializationContext,
            CascadesContext cascadesContext) {
        Plan tempRewritePlan = super.rewriteQueryByView(matchMode, queryStructInfo, viewStructInfo,
                viewToQuerySlotMapping, tempRewritedPlan, materializationContext, cascadesContext);
        if (!StructInfo.checkLimitTmpRewrittenPlanIsValid(tempRewritePlan)) {
            materializationContext.recordFailReason(queryStructInfo,
                    "TopN scan rewriteQueryByView fail because tempRewritePlan is invalid",
                    () -> String.format("tempRewrittenPlan is %s", tempRewritePlan));
            return null;
        }
        Optional<LogicalTopN<Plan>> queryTopN
                = queryStructInfo.getTopPlan().collectFirst(LogicalTopN.class::isInstance);
        Optional<LogicalTopN<Plan>> viewTopN
                = viewStructInfo.getTopPlan().collectFirst(LogicalTopN.class::isInstance);
        return tryRewriteTopN(queryTopN.orElse(null), viewTopN.orElse(null), viewToQuerySlotMapping,
                tempRewritePlan, queryStructInfo, viewStructInfo, materializationContext, cascadesContext);
    }

    @Override
    protected boolean checkQueryPattern(StructInfo structInfo, CascadesContext cascadesContext) {
        PlanCheckContext checkContext = PlanCheckContext.of(ImmutableSet.of());
        Boolean accept = structInfo.getTopPlan().accept(StructInfo.SCAN_PLAN_PATTERN_CHECKER, checkContext);
        return accept
                && !checkContext.isContainsTopAggregate()
                && !checkContext.isContainsTopLimit()
                && checkContext.isContainsTopTopN() && checkContext.getTopTopNNum() == 1;
    }

    @Override
    public List<Rule> buildRules() {
        return ImmutableList.of(
                logicalTopN(subTree(
                        LogicalProject.class, LogicalFilter.class, LogicalCatalogRelation.class))
                        .thenApplyMultiNoThrow(ctx -> {
                            return rewrite(ctx.root, ctx.cascadesContext);
                        }).toRule(RuleType.MATERIALIZED_VIEW_TOP_N_SCAN),
                logicalProject(logicalTopN(subTree(
                        LogicalProject.class, LogicalFilter.class, LogicalCatalogRelation.class)))
                        .thenApplyMultiNoThrow(ctx -> {
                            return rewrite(ctx.root, ctx.cascadesContext);
                        }).toRule(RuleType.MATERIALIZED_VIEW_PROJECT_TOP_N_SCAN)
        );
    }
}