protected void stopCycleUpdater() {
    if (cycleUpdaterExecutorService != null) {
      cycleUpdaterExecutorService.shutdownNow();
      cycleUpdaterExecutorService = null;
    }
  }
Compactor threads that runs in the metastore. It uses a {@link TxnStore}
to access the internal database.
ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/MetaStoreCompactorThread.java