What version of Go are you using (go version)?
Go 1.8

Hi

Sorry for not raising this during the beta, but I just started testing mysql read only transactions.

It appears that query cancellation in mysql would require a non-trivial design go-sql-driver/mysql#496 which might delay the availability of TxOptions.

Perhaps context and TxOptions should be separated into two interfaces as they appear to be two orthogonal concerns..

Something like:

type ConnBeginTx interface {
	BeginTx(opts TxOptions) (Tx, error)
}

type ConnBeginCancelableTx interface {
	BeginCancelableTx(ctx context.Context, opts TxOptions) (Tx, error)
}

Regards,

-Itai