private String getMetadataInJsonFunc() throws TException, IoTDBSQLException {
    TSFetchMetadataReq req = new TSFetchMetadataReq(sessionId, "METADATA_IN_JSON");
    TSFetchMetadataResp resp = client.fetchMetadata(req);
    try {
      RpcUtils.verifySuccess(resp.getStatus());
    } catch (StatementExecutionException e) {
      throw new IoTDBSQLException(e.getMessage(), resp.getStatus());
    }
    return resp.getMetadataInJson();
  }
@deprecated recommend using getMetadataInJson() instead of toString()
iotdb-client/jdbc/src/main/java/org/apache/iotdb/jdbc/IoTDBDatabaseMetadata.java