Application programs can provide key-value connection attributes to be passed to the server at connect time. For descriptions of common attributes, see Section 29.12.9, “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:
- PROCESSLIST_ID- The connection identifier for the session. 
- ATTR_NAME- The attribute name. 
- ATTR_VALUE- The attribute value. 
- ORDINAL_POSITION- The order in which the attribute was added to the set of connection attributes. 
          The session_connect_attrs table
          has these indexes:
- Primary key on ( - PROCESSLIST_ID,- ATTR_NAME)
          TRUNCATE TABLE is not permitted
          for the session_connect_attrs
          table.