PruneEmptyPartition.java

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

import org.apache.doris.catalog.OlapTable;
import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.plans.logical.LogicalEmptyRelation;
import org.apache.doris.nereids.trees.plans.logical.LogicalOlapScan;
import org.apache.doris.qe.ConnectContext;

import java.util.List;

/**
 * Used to prune empty partition.
 */
public class PruneEmptyPartition extends OneRewriteRuleFactory {

    @Override
    public Rule build() {
        return logicalOlapScan().thenApply(ctx -> {
            LogicalOlapScan scan = ctx.root;
            OlapTable table = scan.getTable();
            List<Long> partitionIdsToPrune = scan.getSelectedPartitionIds();
            List<Long> ids = table.selectNonEmptyPartitionIds(partitionIdsToPrune);
            if (ids.isEmpty()) {
                return new LogicalEmptyRelation(ConnectContext.get().getStatementContext().getNextRelationId(),
                        scan.getOutput());
            }
            if (partitionIdsToPrune.equals(ids)) {
                // Not Prune actually, return directly
                return null;
            }
            return scan.withSelectedPartitionIds(ids);
        }).toRule(RuleType.PRUNE_EMPTY_PARTITION);
    }
}