Comment 1:

Good point.  I've ended up implementing that myself a number of times.
Alternatively/additionally, I'd like to see a *DB and optional Driver way to do:
// Ping returns whether the database is available.
func (*DB) Ping() error
But ignoring Ping for now, I think Open getting (& maybe returning or returning in n
seconds) a connection is a good default policy.
But I'd like drivers to be able to opt-out of it.  I'd make a new optional interface on
Driver like:
// OpenInitialer is an optional interface that may be implemented by drivers which
// have a preference on whether an initial connection is created on sql.Open to
// determine the health of the database.  OpenInitial should behave exactly like
// Driver.Open, but the ErrSkip value may be returned to indicate that an initial
// connection should not be opened.
type OpenInitialer interface {
    OpenInitial(name string) (Conn, error)
}
Want to do this?

Labels changed: removed priority-triage.

Status changed to Accepted.

Comment 2:

Mhm, Ping() sounds useful. Time to undeprecate
https://github.com/Go-SQL-Driver/MySQL/blob/master/connection.go#L319
The optional opt-out seems fine to me.
Right now I have no time to implement this since it's finals time (fun fact: next one is
on ... surprise: databases) so don't hesitate to start working on this.

Comment 3:

The finals are mastered, so I start working on this now.
Whats your opinion on yet another optional interface which allows to "clone"
connections? So the driver doesn't need to parse the DSN again. Maybe the driver also
queried some server vars which could be taken over instead of querying them again or
there are some other checks / operations a driver might skip.
So the first connection is opened with Driver.OpenInitial(dsn) and for all further
connections opened internally by the sql package just Conn.Clone().

Comment 4:

[The time for maybe has passed.]

Labels changed: removed go1.1maybe.

Comment 5:

Sent out https://golang.org/cl/7819043

Owner changed to @bradfitz.

Status changed to Started.

Comment 6:

This issue was closed by revision a4a8651.

Status changed to Fixed.

Comment 7:

To be clear, this was "Fixed" by documenting the status quo instead, and adding a Ping
method.

Comment 8:

Can you please reopen the issue?
We have a workaround now, but it is not as 'fixed' as it should be in the long term.

Comment 9:

It's not clear to me that changing the status quo is appropriate.  It appears that it's
straightforward to get the functionality you want.
I'll leave it for Brad to decide whether we should change Open.