[Zope] Re: Fwd: [Zope] postgres DA

[Jim Sanford]

Someone please correct me if I have gotten the stuff below wrong.
-------------------
If I read the stuff on the PoPy web site correctly, it is a Level 2 Database
Adapter that is level 1 thread safe.

The level 1 refers to level of thread safety not database adapter level.

Level 1 thread safety means that multiple threads can share the module but
each thread must have its own database connection.

Level 2 thread safety means that multiple threads can share the module and
connections.

Level 3 thread safety means that multiple threads can share the module and
connections and cursors.

----- Original Message -----
From: "Bak @ kedai" <kedai@kedai.com.my>
To: "Federico Di Gregorio" <fog@mixadlive.com>
Cc: <zope@zope.org>
Sent: Friday, June 02, 2000 4:10 AM
Subject: [Zope] Re: Fwd: [Zope] postgres DA


> I can only say that we started writing PoPy and ZPoPyDA because pygresql
> (and the adapter based on it) are *not* thread safe. we were experimenting
> deadlocks in zope when you mix db access from sql methods and external
> methods in the same page.

quoting DAroadmap at
http://www.zope.org/Members/petrilli/DARoadmap
"""

Level 2

                    Level 2 database adapters must be safe to use in a
multi-threaded Zope instance. This can take multiple behaviour
                    paterns:

                        Internal locking/mutexes for single DA access

                        Global locking through the transaction manager if
appropriate

                    While a sub-optimal solution, it should be usable on any
application that has minimal, or infrequent, database access.
                    This means that all access paterns will be serialized.

                    In addition, all DAs at this level must release the
Python global interpreter lock.
"""
i assume ZPoPyDA conform to the above statement.  will you make ZPoPyDa into
level 3 anytime soon?

>
> on the other hand PoPy is pretty new and, before using it in production,
> needs more testing. i think it will stabilize pretty soon, because we will
> use it to build the web sites for our customers really soon now and that
> will apport a lot of testing/debugging.
>

i will try ZPoPyDA on my personal site, and will inform you of any
misbehaviour.  BTW, what symptoms should i look out for if ZPoPyDa
misbehave?
Zope locking/not responding?


>make your choice and be happy,
made mine already, thanks, and

"""
I'll be back!
"""


> federico
>
> --
> Federico Di Gregorio
> MIXAD LIVE System Programmer                           fog@mixadlive.com
> Debian GNU/Linux Developer & Italian Press Contact        fog@debian.org
>           The reverse side also has a reverse side.  -- Japanese proverb
--
------------------------------------------------------
http://www.kedai.com.my/kk
Am I Evil?


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