Application programs can provide key/value connection
attributes to be passed to the server at connect time, using
mysql_options4() C API
functions. For descriptions of common attributes, see
Section 25.11.9, “Performance Schema Connection Attribute Tables”.
table contains these columns:
The connection identifier for the session.
The attribute name.
The attribute value.
The order in which the attribute was added to the set of connection attributes.
table has these indexes:
Primary key on (