public void clearChildZNodes() throws KeeperException {
    LOG.debug("Clearing all znodes {}, {}, {}", acquiredZnode, reachedZnode, abortZnode);

    // If the coordinator was shutdown mid-procedure, then we are going to lose
    // an procedure that was previously started by cleaning out all the previous state. Its much
    // harder to figure out how to keep an procedure going and the subject of HBASE-5487.
    ZKUtil.deleteChildrenRecursivelyMultiOrSequential(watcher, true, acquiredZnode, reachedZnode,
      abortZnode);

    if (LOG.isTraceEnabled()) {
      logZKTree(this.baseZNode);
    }
  }
Helper method to print the current state of the ZK tree.
@see #logZKTree(String)
@throws KeeperException if an unexpected exception occurs
hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/ZKProcedureUtil.java