Hi Terry, I never done this before, but I think you should take care about transaction commit which is done after each request. So if you start a new thread, you probably have to get a new connection to ZODB, do what you need to do, and commit it. regards, Michal On Sat, Jun 22, 2002 at 06:11:43AM -0700, Terry Hancock wrote:

Hi all,

As yet another iteration in a very image intensive product, I'm trying to build a tree of images. They are generated procedurally, and may differ from installation to installation (they don't currently, but they probably will).

So it's much more convenient to generate them procedurally in the manage_add<my-product>() function than to store them in, say, a .zexp file. (I also tried making them on-the- fly, but that's a whole 'nother story).

Nevertheless, it takes quite awhile for PIL to chunk through all those images (currently 2880).

If I just use a straight iteration, the browser will time-out during the installation process, which is kind of ugly, and will no doubt freak out my potential user/ administrator. Also, it's not absolutely clear to me that Zope won't cut me off somehow if my request takes too long. (Any reassurances/warnings on this point?).

Alternatively, I can put components of the installation process into separate threads. This nicely drops me back into the management interface and runs the object-building process in the background. However, I then have to think about checking it to make sure it's done (probably I can handle this, though I haven't yet -- I just check it manually later).

The big headache though, is that with the threaded version, I have folders disappear out of the management interface!

If I wait long enough, eventually they just start to disappear. Same thing if I restart. So the persistence machinery must not be working in the threaded case.

But why not?

The code is essentially the same, except that in the non-threaded version I just call the function, whereas in the threaded version, I create a thread to run it with threading.Thread(). I do this at the highest level in the loop, which means about 4 threads should be started, which I wouldn't think would tax my system (an earlier version with about 50 threads did cause a massive slowdown).

Both versions use ordinary 'Folder' objects and create them using the Zope API with manage_addFolder() calls on the parent folders.

Should I abandon threading here? (and just document this in the INSTALL file). Should I use full-fledged processes? Or am I just forgetting to do something?

(I've done almost no threaded programming before this -- I did run a threaded test version of this code that generated the files on the filesystem outside of Zope. All my tests with that version went fine.).

Thanks in advance for any ideas, Terry

-- ------------------------------------------------------ Terry Hancock hancock@anansispaceworks.com Anansi Spaceworks http://www.anansispaceworks.com P.O. Box 60583 Pasadena, CA 91116-6583 ------------------------------------------------------

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