Performance Schema Miscellaneous Tables is the case if any  admin_tls_ xxx  or  admin_ssl_ xxx  system variable is set to a value different from its default.) Otherwise, the administrative interface uses the same TLS context as the main interface. The  tls_channel_status  table has no indexes. TRUNCATE TABLE  is not permitted for the  tls_channel_status  table. The  user_defined_functions  table contains a row for each loadable function registered automatically by a component or plugin, or manually by a  CREATE FUNCTION  statement. For information about operations that add or remove table rows, see Section 5.7.1, “Installing and Uninstalling Loadable Functions” . 27.12.21.8 The user_defined_functions Table The name of the  user_defined_functions  table stems from the terminology used at its inception for the type of function now known as a loadable function (that is, user-defined function, or UDF). Note The  user_defined_functions  table has these columns: The function name as referred to in SQL statements. The value is  NULL  if the function was registered by a  CREATE FUNCTION  statement and is in the process of unloading. The function return value type. The value is one of  int ,  decimal ,  real ,  char , or  row . The function type. The value is one of  function  (scalar) or  aggregate . The name of the library file containing the executable function code. The file is located in the directory named by the  plugin_dir  system variable. The value is  NULL  if the function was registered by a component or plugin rather than by a  CREATE FUNCTION  statement. The current function usage count. This is used to tell whether statements currently are accessing the function. The  user_defined_functions  table has these indexes: TRUNCATE TABLE  is not permitted for the  user_defined_functions  table. The  mysql.func  system table also lists installed loadable functions, but only those installed using CREATE FUNCTION . The  user_defined_functions  table lists loadable functions installed using CREATE FUNCTION  as well as loadable functions installed automatically by components or plugins. This difference makes  user_defined_functions  preferable to  mysql.func  for checking which loadable functions are installed. • UDF_NAME • UDF_RETURN_TYPE • UDF_TYPE • UDF_LIBRARY • UDF_USAGE_COUNT •Primary key on ( UDF_NAME ) 5095