Performance Schema User-Defined Variable Tables The  session_account_connect_attrs  table has these indexes: TRUNCATE TABLE  is not permitted for the  session_account_connect_attrs  table. Application programs can provide key-value connection attributes to be passed to the server at connect time. For descriptions of common attributes, see Section 27.12.9, “Performance Schema Connection Attribute Tables” . The  session_connect_attrs  table contains connection attributes for all sessions. To see connection attributes only for the current session, and other sessions associated with the session account, use the session_account_connect_attrs  table. The  session_connect_attrs  table has these columns: The connection identifier for the session. The attribute value. The attribute name. The order in which the attribute was added to the set of connection attributes. The  session_connect_attrs  table has these indexes: TRUNCATE TABLE  is not permitted for the  session_connect_attrs  table. The Performance Schema provides a  user_variables_by_thread  table that exposes user-defined variables. These are variables defined within a specific session and include a  @  character preceding the name; see Section 9.4, “User-Defined Variables” . The  user_variables_by_thread  table has these columns: The thread identifier of the session in which the variable is defined. The variable name, without the leading  @  character. •Primary key on ( PROCESSLIST_ID ,  ATTR_NAME ) • PROCESSLIST_ID • ATTR_NAME • ATTR_VALUE • ORDINAL_POSITION •Primary key on ( PROCESSLIST_ID ,  ATTR_NAME ) • THREAD_ID • VARIABLE_NAME • VARIABLE_VALUE 27.12.10 Performance Schema User-Defined Variable Tables 4996 27.12.9.2 The session_connect_attrs Table