CheckScoreUsage.java

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// 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
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

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

import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.expressions.Alias;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.scalar.Score;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalAggregate;
import org.apache.doris.nereids.trees.plans.logical.LogicalOlapScan;
import org.apache.doris.nereids.trees.plans.logical.LogicalProject;

import com.google.common.collect.ImmutableList;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.List;

/**
 * Reject score() calls outside a supported scan scoring context.
 * Aggregates cannot consume raw score() calls.
 */
public class CheckScoreUsage implements RewriteRuleFactory {
    private static final Logger LOG = LogManager.getLogger(CheckScoreUsage.class);
    private static final String SCORE_CONTEXT_ERROR =
            "score() function requires WHERE clause with MATCH function, ORDER BY and LIMIT for optimization, "
                    + "or a supported minimum score filter with MATCH or SEARCH";

    @Override
    public List<Rule> buildRules() {
        return ImmutableList.of(
            logicalProject(any())
                .when(project -> {
                    boolean hasScore = hasScoreFunction(project);
                    boolean isOptimized = isScoreAlreadyOptimized(project);
                    LOG.debug("Project check - hasScore: " + hasScore + ", isOptimized: " + isOptimized);
                    return hasScore && !isOptimized;
                })
                .then(project -> {
                    throw new AnalysisException(SCORE_CONTEXT_ERROR);
                }).toRule(RuleType.CHECK_SCORE_USAGE),

            // A filter-only score() call otherwise evaluates the scalar placeholder as zero.
            logicalFilter(any())
                .when(filter -> filter.getConjuncts().stream().anyMatch(this::containsScoreFunction))
                .then(filter -> {
                    throw new AnalysisException(SCORE_CONTEXT_ERROR);
                }).toRule(RuleType.CHECK_SCORE_USAGE),

            logicalAggregate(any())
                .when(this::hasScoreInAggregate)
                .then(agg -> {
                    throw new AnalysisException("score() function cannot be used in aggregate functions.");
                }).toRule(RuleType.CHECK_SCORE_USAGE)
        );
    }

    private boolean hasScoreFunction(LogicalProject<?> project) {
        return project.getProjects().stream()
                .anyMatch(projection -> {
                    if (projection instanceof Alias) {
                        return containsScoreFunction(((Alias) projection).child());
                    }
                    return false;
                });
    }

    private boolean hasScoreInAggregate(LogicalAggregate<?> agg) {
        boolean hasScoreInOutput = agg.getOutputExpressions().stream()
                .anyMatch(this::containsScoreFunction);

        boolean hasScoreInGroupBy = agg.getGroupByExpressions().stream()
                .anyMatch(this::containsScoreFunction);

        if (hasScoreInOutput || hasScoreInGroupBy) {
            return true;
        }
        // Aggregate normalization can move score() arguments into the child projection.
        Plan child = agg.child();
        return child instanceof LogicalProject && hasScoreFunction((LogicalProject<?>) child);
    }

    private boolean containsScoreFunction(Expression expr) {
        if (expr instanceof Score) {
            return true;
        }
        return expr.children().stream().anyMatch(this::containsScoreFunction);
    }

    private boolean isScoreAlreadyOptimized(LogicalProject<?> project) {
        Plan child = project.child();
        if (child instanceof LogicalOlapScan) {
            LogicalOlapScan scan = (LogicalOlapScan) child;
            return scan.getVirtualColumns().stream()
                    .anyMatch(virtualCol -> {
                        if (virtualCol instanceof Alias) {
                            Expression childExpr = ((Alias) virtualCol).child();
                            return containsScoreFunction(childExpr);
                        }
                        return false;
                    });
        }
        return false;
    }
}