@Override
  public void refresh() {
    HiveConf conf = ctx.getConf();
    sleepTime = conf.getTimeVar(
        HiveConf.ConfVars.HIVE_LOCK_SLEEP_BETWEEN_RETRIES, TimeUnit.MILLISECONDS);
    numRetriesForLock = conf.getIntVar(HiveConf.ConfVars.HIVE_LOCK_NUMRETRIES);
    numRetriesForUnLock = conf.getIntVar(HiveConf.ConfVars.HIVE_UNLOCK_NUMRETRIES);
  }
shared lock manager for dedicated hive server. all locks are managed in memory
ql/src/java/org/apache/hadoop/hive/ql/lockmgr/EmbeddedLockManager.java