connect con1,localhost,root,,test,,;
connect con2,localhost,root,,test,,;
connection con1;
set session debug_dbug="t";
show session variables like 'debug_dbug';
Variable_name	Value
debug_dbug	t
connection con2;
set session debug_dbug="t";
show session variables like 'debug_dbug';
Variable_name	Value
debug_dbug	t
connection con1;
set session debug_dbug="d:t";
show session variables like 'debug_dbug';
Variable_name	Value
debug_dbug	d:t
connection con2;
show session variables like 'debug_dbug';
Variable_name	Value
debug_dbug	t
disconnect con1;
disconnect con2;
connection default;