public CacheNode searchChild(String name) {
      String[] nodeNames = name.split("\\.");
      CacheNode current = this;
      for (String nodeName : nodeNames) {
        if (nodeName.equals("root")) {
          continue;
        }
        current = current.getChild(nodeName);
        if (current == null) {
          return null;
        }
      }
      return current;
    }
Search the child node by name.

@param name the name corresponding to the child node, use '.' to separate each node
@return the child node if it exists, otherwise return null
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/schema/ttl/TTLCache.java