RE: [cx-oracle-users] Session Pooling

[Orr, S. <so...@ri...>]

So long without answers? Are my questions too hard?  :-)

I was wrong about the SessionPool.timeout attribute. It works just fine.
I can configure the number of processes which Apache spawns and even
though each process establishes a reusable pool of database connections
they level off with inactivity and scale up when needed. Pooling
connections with cx_Oracle/Apache/mod_python serves up data driven web
pages really FAST!=20

I'm still wondering about the ramifications of adding connections with
different credentials than what the session pool was created with.=20

I'd also like to get some feedback on caching cursors. It seems like I
saw some code for that in the cx utilities or whatever. I'm just
wondering how much coding effort is required and what's the benefit?=20

Steve Orr


-----Original Message-----
From: cx-...@li...
[mailto:cx-...@li...] On Behalf Of Orr,
Steve
Sent: Monday, August 01, 2005 11:28 AM
To: cx-...@li...
Subject: [cx-oracle-users] Session Pooling

I'm looking to use session pooling for performance (Apache 2.0,
mod_python, Quixote 2.0, cx_Oracle 4.x Oracle9). Here's some code for
reference:
import cx_Oracle
class dbconnect(cx_Oracle.Connection):
    def __init__(self, user=3DNone, password=3DNone, dsn=3DNone, =
pool=3DNone):
        cx_Oracle.Connection.__init__(self, user=3Duser,
password=3Dpassword,
                                      dsn=3Ddsn, pool=3Dpool)
        self.pool =3D pool
    def close(self):
        self.pool.release(self)
class dbfun(object):
    def __init__(self):
        self.pool =3D cx_Oracle.SessionPool('user', 'pw', 'local', 1, 8,
1)
        self.pool.timeout =3D 30
    def connect(self, user, password, dsn):
        conn =3D dbconnect(user=3Duser, password=3Dpassword,=20
                         dsn=3Ddsn, pool=3Dself.pool)
        return conn

Basically I subclassed the cx_Oracle connection object to over-ride the
close function to release a connection to the pool instead of closing
it.=20

Observations and Questions:
Setting the timeout attribute doesn't seem to change anything, no
connections are returned to the pool after 30 seconds. Is this a bug or
am I doing something wrong?=20

If I exceed the session limit from Python it just hangs... Shouldn't
cx_Oracle.Connection return an exception? Do I really HAVE to compare
pool.busy and pool.opened in my code and raise my own exception?=20

I found that if I kill a session from SQL*Plus it does not become
available to the pool. Well okay.

I found that when connecting through my dbfun class I could connect with
a different user/password than was established in the pool. What are the
ramifications of this? If I want to pool connections from different
users do I need to create distinct pools for each user ID?

Are there any other suggestions or sample code on how to implement
connection pooling? Has anyone cached cursors and is it worth it?=20

TIA,
Steve Orr


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