public boolean wasMatched(int logicalSlotNum) {
    final int longWordIndex = logicalSlotNum / Long.SIZE;
    final long longBitMask = 1L << (logicalSlotNum % Long.SIZE);
    return (longMatchFlags[longWordIndex] & longBitMask) != 0;
  }
Record which hash table slot entries had key matches for FULL OUTER MapJoin.
Supports partitioned match trackers for HybridHashTableContainer.
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/MatchTracker.java