The speed issues may be fixable without a rewrite, but frankly the Everything code is not very well suited to its current use on PerlMonks. It has some fundamental design decisions (keeping the code in the database, doing most of the data as generic blobs of XML) which are a major cause of slowness and race conditions, but more importantly make it really hard for most people to contribute to the code and make testing nearly impossible. How could anyone profile this code effectively? Just retrieving it to run on your own system requires significant work (because you have to get it out of the PerlMonks database and test data is not available).

It's very cool that the system was designed flexibly enough to work in this way, but a more focused codebase that works specifically for PerlMonks would be able to run much more efficiently. PerlMonks is essentially a separate codebase now, since it branched off the Everything codebase a long time ago and is not able to take updates from that code unless someone manually merges them in.

I would like to believe that a gradual process of rewriting could fix these issues, but I'm not sure it will because the things that need to be changed are so fundamental to the current design. Your point about all the accumulated knowledge in this code is a very good one though, and not to be dismissed lightly. Rewriting would be a lot of work and it would be hard to get all of the current functionality right. Migrating the data would be REALLY hard.

Caching with mod_perl, on the other hand, is trivial. I gave a talk about it at OSCON last year and I'd be happy to help if you have questions about it. Tye was concerned that using shared caching anywhere other than the nodelets would make the race conditions worse, but doing the caching itself is simple. (Of course caching across a cluster is hard, but that has nothing to do with mod_perl and may not be required.)

In reply to Re: Re: redesign everything engine? by perrin
in thread redesign everything engine? by Jaap

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