Re: [cx-oracle-users] How to transparently re-connect using cx_Oracle?

[Laurelin of M. E. <la...@fn...>]

Thus spaketh Anthony Tuininga on 10/05/2006 11:23 AM:

 > On 10/4/06, Laurelin of Middle Earth <la...@fn...> wrote:
 >
 >> [snippage]
 >>Unless the cx_Oracle.Connection instance knows how to reconnect
 >>itself....
 >
 >
 > It doesn't currently -- but its entirely possible that it could. Of
 > course any current cursors would be invalidated by such a move. That
 > might end up causing more trouble than its worth.... As has already
 > been noted attempting to restart something in the middle may not be
 > very effective as well. Are you certain that this is the solution you
 > need and would a reconnect() method help you? Would you need this
 > "right away" as well?
 >

My RetryHandler knows about certain "transactions" -- that is, things
that require both "execute" (or "callfunc") and a series of one or
more "fetchXXX" calls.  If any of the elements fails, it will go back
to the beginning of the transaction.  So I think I've handled the
case of "restarting something in the middle", at least for the
situations of interest to me.

As for invalidating current cursors... hmmm.... I guess I don't
understand (but that's not unusual ;-).  My hope was that the cursor
would become "usable" again by re-connecting its existing connection
rather than creating a new connection.  Of course you cannot continue
with anything that you are currently executing in that cursor -- but
if the connection is dead, then the cursor can't be doing much of
anything anyway, right?

In my case, what I was hoping could happen would be something along
the lines of the pseudo-code:

     done = False
     while not done:
        try:
	  cursor.callfunc(...)
	  cursor.do_whatever_fetch_XXX(...)
	  done = True

        except ConnectionIsDeadException:
           cursor.connection.reconnect()

        except RetriableException:
            pass


"Right away"?  Yes, of course -- yesterday would be optimal.  ;-)  No,
we have a workaround that is getting us by for the time being, and I'm
not presumptuous enough to think that you have free time to spend on
solving my problems.  "At your convenience (but the sooner the better)"
is just fine.

Thanks, lauri