Re: [cx-oracle-users] is SessionPool thread safe?

[Anthony T. <ant...@gm...>]

Ok, I'll try again. :-) As far as I know the session pool acquire
method is thread safe. There is no Oracle documentation that says
otherwise and the description of OCI_THREADED mode seems to imply that
it is thread safe. We have also done precisely what you are doing
(acquiring a connection from a pool in a worker thread) in our own
product and have never run into a problem. If we forget to set
"threaded =3D True" in the session pool constructor, though, all kinds
of trouble occurs. :-) Does that answer your question sufficiently
now?

On 9/15/05, Forest Wilkinson <mo...@ti...> wrote:
> Thanks for the response, but I'm afraid it doesn't explain the matter.  I=
t
> tells me how Connection objects behave when shared among threads, but it
> does not tell me how SessionPool objects behave when shared among threads=
.
>=20
> One interpretation of what you wrote (and of the documentation) is that
> SessionPool.acquire() returns a thread-safe object when it was constructe=
d
> with threaded=3DTrue, but the SessionPool.acquire() call itself is not
> thread safe.  If that is the case, a program's main thread could safely
> acquire() Connections and then pass them to worker threads, but multiple
> worker threads could not safely call acquire() on their own.
>=20
> My program's worker threads have to acquire() Connections on an as-needed
> basis, rather than being handed a Connection when they start up.  The
> answer to my question will determine whether I have to write my own
> synchronization wrapper for SessionPool.acquire().
>=20
> Anthony Tuininga <ant...@gm...> wrote:
>=20
> > If you specify "threaded =3D3D True" in the constructor of the session
> > pool, Oracle guarantees thread safety provided you use one thread for
> > each connection you use. If you want more than one thread to access a
> > connection, you will have to synchronize access. Does that explain the
> > matter sufficiently?
> >
> > On 9/12/05, Forest Wilkinson <mo...@ti...> wrote:
> >
> >>I'm using cx_Oracle SessionPool objects in a threaded http server.  Sin=
ce
> >>I didn't see an explicit statement in the docs that SessionPool.acquire=
()
> >>and SessionPool.release() are thread safe, I'm currently synchronizing
> >>access to those methods with a threading.Condition object.  Is this
> >>necessary?  If SessionPool does its own method synchronization, I'll ge=
t
> >>rid of my wrapper class and perhaps get better performance.
> >>=3D20
> >>=3D20
>=20
>=20
>=20
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