Hi Marcus,
thanks for your patch. I applied it, please cross check :-)
Carsten
> -----Ursprungliche Nachricht-----
> Von: Marcus Crafter [mailto:[EMAIL PROTECTED]]
> Gesendet: Samstag, 18. August 2001 22:41
> An: Cocoon Developers Mailing List
> Betreff: [C2] sitemap creation threading issue ?
>
>
> Hi *,
>
> Hope all is well.
>
> Michael and I have spent the day testing our C2 application with
> LoadRunner and have potentially uncovered a threading problem during
> sitemap creation.
>
> We're not experts with the code but from our understanding the
> following is happening, please let us know if we are right/wrong:
>
> There seems to be a problem with the getHandler() method, located in
> the sitemap Manager class (line 154). getHandler() attempts
> to access a
> sitemap handler object for each request for processing. If
> the handler
> object is not available it creates one, causing the sitemap to be
> generated.
>
> We've noticed under load, that many handler objects are created for
> the same sitemap. This is because getHandler() does not protect the
> following lines:
>
> Handler sitemapHandler = (Handler)sitemaps.get(source);
>
> and
>
> sitemaps.put(source, sitemapHandler);
>
> as a critical area.
>
> If multiple concurrent threads pass through getHandler() which are
> requests for resources from the same sitemap, the first line
> above will return null multiple times causing the same sitemap to be
> compiled several times, each by individual Handler objects.
>
> This happens because sitemaps.put() executes after each
> sitemap handler
> object is created (which can take time for large sitemaps),
> and cannot
> prevent other incoming threads from waiting until it adds the newly
> created handler object into the 'sitemaps' hashmap.
>
> When we synchronized the getHandler method to protect the
> getting/setting of the sitemaps hashmap, we saw that the sitemap
> handler object was created only once, and that the application
> performed much better under load. Previously the same
> sitemap handler
> object was created as many times as we had simultaneous threads
> make requests.
>
> Attached is a diff of the change we made. There might be a better
> solution as the Handler class seems to be built to handle this, it's
> just that the allocation of a new Handler objects per
> sitemap, defeats
> it's internal multi-thread logic.
>
> Any comments/thoughts/suggestions ?
>
> Cheers,
>
> Marcus
>
> --
> .....
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