Re: Error during garbage collection after calling isready() on a closed connection

Il giorno gio, 15/01/2009 alle 17.26 +0100, Brian Sutherland ha scritto:
> On Sat, Jan 10, 2009 at 07:08:24PM +0100, Federico Di Gregorio wrote:
> > Il giorno ven, 09/01/2009 alle 17.13 +0200, Brian Sutherland ha scritto:
> > > Hi,
> > > 
> > > Attached is an example script of a nasty little bug I found. It looks
> > > like calling .isready() on a server closed connection causes an error
> > > during the next garbage collection. That can cause all sorts of havoc on
> > > a python process.
> > > 
> > > I found it in version 2.5.1 and verified that it's still there in 2.0.8.
> > 
> > Hi,
> > 
> 
> I've backported your patch to 2.0.5.1 and it seems to work perfectly.
> Thanks!
> 
> > cursor.isready() now raise an exception if the internal call to libpq
> > reports problems. This is probably now _exactly_ what you want because
> > the first call to isready() after the disconnection results in a notice
> > (correctly appended to connections notices) and not in an error. An
> > error will be raised on any successive call that try to use the now
> > dropped connection.
> 
> Yes, raising an error on the isready() is _exactly_ what I want :)
[snip]
> In my application whether the exception is raised on the first or the
> second isready() calls isn't important. In fact, I can't think of a
> situation where it's important that the exception be raised exactly on
> the first isready() call after the connection is dropped.

Ah.. fine.

Have fun with psycopg,

federico

-- 
Federico Di Gregorio                         http://people.initd.org/fog
Debian GNU/Linux Developer                                [email protected]
INIT.D Developer                                           fog-NGVKUo/i/[email protected]
 In science one tries to tell people, in such a way as to be understood
  by everyone, something that no one ever knew before. But in poetry,
  it's the exact opposite.                                 -- Paul Dirac

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