[Twisted-Python] Lock classes for berkely dbm files

[Jp Calderone]

On Sun, 13 Feb 2005 19:09:14 -0800, snacktime <snacktime at gmail.com> wrote:
>Anyone have any thoughts on using a lock class (using deferreds)
> versus the built in transaction/locking support in BerkeleyDB?
> 
> My thought was this.  It sure would be a lot simpler to just use a
> lock class and the python built in dbm functions than having to use
> the newer bsddb3 module and worry about BerkeleyDb environments and
> transactions.
> 
> The application is transaction oriented, and each transaction would 
> have one write and one read, each in a different lock.
> 
> Anyone see any problems with using a lock class in this way?

  Just that it totally won't work at all.  Use the newer bsddb3 
module, if you plan to use a string key/value mapping-oriented 
data store.

  To avoid worrying about bdb environments, you want the 
DatabaseEnvironment class from this module:

    http://divmod.org/cvs/*checkout*/trunk/atop/store.py?content-type=text%2Fplain&rev=7420

  Specifically, the open() (and possibly join()) method.

  Jp