In article <[EMAIL PROTECTED]>, Paul Rubin <http://[EMAIL PROTECTED]> wrote: >I've started a few threads before on object persistence in medium to >high end server apps. This one is about low end apps, for example, a >simple cgi on a personal web site that might get a dozen hits a day. >The idea is you just want to keep a few pieces of data around that the >cgi can update. > >Immediately, typical strategies like using a MySQL database become too >big a pain. Any kind of compiled and installed 3rd party module (e.g. >Metakit) is also too big a pain. But there still has to be some kind >of concurrency strategy, even if it's something like crude file >locking, or else two people running the cgi simultaneously can wipe >out the data store. But you don't want crashing the app to leave a >lock around if you can help it. > >Anyway, something like dbm or shelve coupled with flock-style file >locking and a version of dbmopen that automatically retries after 1 >second if the file is locked would do the job nicely, plus there could >be a cleanup mechanism for detecting stale locks. > >Is there a standard approach to something like that, or should I just >code it the obvious way? > >Thanks.
I have a couple of oblique, barely-helpful reactions; I wish I knew better solutions. First: I'm using Metakit and SQLite; they give me more confidence and fewer surprises than dbm. Second: Locking indeed is a problem, and I haven't found a good global solution for it yet. I end up with local fixes, that is, rather project-specific locking schemes that exploit knowledge that, for example, there are no symbolic links to worry about, or NFS mounts, or ... Good luck. -- http://mail.python.org/mailman/listinfo/python-list
