David Strauss started a great discussion on the development list about one-to-one tables this week that could impact comments and potentially forums... since, as Dries points out, forums is one of the 5 core modules that use the node_comment_statistics table David wants to eliminate.
I'm not that interested in database optimization so I haven't been following the thread that closely, but I am interested in major changes to schemas that may impact user contributed modules I use.
Can anyone for familiar with interworkings of the modules that extend and improve forums or the work being done to improve the core comment on how the changes David is proposing would impact these?
Another thread/idea that David started is requiring node revisions for all updates and making preview an uncommitted node revision. It seems like this would be another change that could impact forum interface/usability.
Comments
The big changes with that
The big changes with that one-to-one tables patch will be a massive (20-200 times or something) speed increase on the tracker and forum indexes. Anyone with a busy community site should notice the difference.
Off the top of my head I can't think of any modules that particularly use node_comment_statistics which extend forums. Obviously views, but the end-user functionality shouldn't be any different when that's upgraded for 6.x, except for being massively speeded up. The worst that'll happen and extra stage for module upgrades as far as I can see.
The "revisions as previews" idea could be very good as well. It'd allow you to preview a post, then if you wanted to go back a couple of pages to check a comment, you could do this in the knowledge that your draft post would be saved for later retrieval. Until the browser cache/back button error was fixed in 5.x this was a major issue on our site with people clicking back then forwards and being presented with an empty comment form. Saving posts as unpublished revisions would be a further step in protecting user data from errors if it's applied to comments - see next paragraph.
I know there's some work on trying to refactor comments to use nodes (and deal with the performance implications of that at the same time). I'm not sure how far along that is except for the comments as nodes module which there's a benchmark of in this group. However, comments as nodes opens up all kinds of possibilities if it gets through - for example having a user tracker where you can view all their actual comments, rather than simply forum topics (where their comment might be #900 out of #2100) - great for seeing what different users are talking about, and tracking trolls and spammers as well. It should also allow for modules like forum_access to allow for more granular comment moderation, all kinds of things, including hopefully my favourite issue, #new links not working over multiple pages which the current comment.module makes a very, very hard thing to fix.