Performance Schema Connection Attribute Tables • _program_name : The client name. • _thread : The client thread ID (Windows only). •Compiled using  libmysqlclient : The standard  libmysqlclient  attributes, described previously. •Compiled using  mysqlnd : Only the  _client_name  attribute, with a value of  mysqlnd . • mysql  (as of MySQL 8.0.17): • os_user : The name of the operating system user running the program. Available on Unix and Unix- like systems and Windows. • os_sudouser : The value of the  SUDO_USER  environment variable. Available on Unix and Unix-like systems. • mysqlbinlog : • _client_role :  binary_log_listener •Replica connections: • program_name :  mysqld • _client_role :  binary_log_listener • _client_replication_channel_name : The channel name. • FEDERATED  storage engine connections: • program_name :  mysqld • _client_role :  federated_storage •A fixed limit imposed by the client prior to connect time. •A fixed limit imposed by the server at connect time. •A configurable limit imposed by the Performance Schema at connect time. Connection Atrribute Limits 4994 There are limits on the amount of connection attribute data transmitted from client to server: For connections initiated using the C API, the  libmysqlclient  library imposes a limit of 64KB on the aggregate size of connection attribute data on the client side: Calls to  mysql_options()  that cause this limit to be exceeded produce a  CR_INVALID_PARAMETER_NO  error. Other MySQL Connectors may impose their own client-side limits on how much connection attribute data can be transmitted to the server. mysql  connection attributes for which the value is empty are not sent. Some MySQL client programs define additional attributes: Many MySQL client programs set a  program_name  attribute with a value equal to the client name. For example,  mysqladmin  and  mysqldump  set  program_name  to  mysqladmin  and  mysqldump , respectively. MySQL Shell sets  program_name  to  mysqlsh . PHP defines attributes that depend on how it was compiled: