public Path getWhRootExternal() throws MetaException {
    if (whRootExternal != null) {
      return whRootExternal;
    }
    if (!hasExternalWarehouseRoot()) {
      whRootExternal = getWhRoot();
    } else {
      whRootExternal = getDnsPath(new Path(whRootExternalString));
    }
    return whRootExternal;
  }
Resolve the configured warehouse root dir with respect to the configuration
This involves opening the FileSystem corresponding to the warehouse root
dir (but that should be ok given that this is only called during DDL
statements for non-external tables).
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/Warehouse.java