NestedLoopJoinStatsDerive.java

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// to you under the Apache License, Version 2.0 (the
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.doris.statistics;

import org.apache.doris.common.CheckedMath;

import com.google.common.base.Preconditions;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * Derive NestedLoopJoinNode statistics.
 */
public class NestedLoopJoinStatsDerive extends BaseStatsDerive {
    private static final Logger LOG = LogManager.getLogger(NestedLoopJoinStatsDerive.class);

    @Override
    protected long deriveRowCount() {
        Preconditions.checkState(childrenStatsResult.size() == 2);
        if (childrenStatsResult.get(0).getRowCount() == -1 || childrenStatsResult.get(1).getRowCount() == -1) {
            rowCount = -1;
        } else {
            rowCount = CheckedMath.checkedMultiply((long) childrenStatsResult.get(0).getRowCount(),
                    (long) childrenStatsResult.get(1).getRowCount());
            applyConjunctsSelectivity();
            capRowCountAtLimit();
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("stats CrossJoin: rowCount={}", Double.toString(rowCount));
        }
        return rowCount;
    }
}