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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. 

## 27.12.21.8 The user_defined_functions Table 

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” . 

<img src='content_image/758777.jpg'>

The user_defined_functions  table has these columns: 

• UDF_NAME 

## Note 

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). 

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. 

• UDF_RETURN_TYPE 

The function return value type. The value is one of int , decimal , real , char , or row . 

• UDF_TYPE 

The function type. The value is one of function  (scalar) or aggregate . 

• UDF_LIBRARY 

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. 

• UDF_USAGE_COUNT 

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: 

•Primary key on ( UDF_NAME ) 

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. 

