EliminateLimitUnderApply.java

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

import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.plans.Plan;

import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * EliminateLimitUnderApply.
 */
public class EliminateLimitUnderApply extends OneRewriteRuleFactory {
    @Override
    public Rule build() {
        return logicalApply(any(), logicalLimit()).then(apply -> {
            if (!apply.isCorrelated()) {
                // must keep the limit if it's an uncorrelated because the return number of rows is affected by limit
                return null;
            }
            List<Plan> children = new ImmutableList.Builder<Plan>()
                    .add(apply.left())
                    .add(apply.right().child())
                    .build();
            return apply.withChildren(children);
        }).toRule(RuleType.ELIMINATE_LIMIT_UNDER_APPLY);
    }
}