>
> 	o Prevent tab completion of SET TRANSACTION from querying the
> 	  database and therefore preventing the transaction isolation
> 	  level from being set.
>
> 	  Currently, SET <tab> causes a database lookup to check all
> 	  supported session variables.  This query causes problems
> 	  because setting the transaction isolation level must be the
> 	  first statement of a transaction.