Ok. That all makes sense.

To clarify where we are now and our glorious future, I see the plan as this:

"normal search" (that's the term I'm using) is different than "advanced search". In "normal search", users search the kb and support forums and that's it. Advanced search lets contributors search everything else, but only one thing at a time (i.e. you search the kb OR support forums OR contributor forums, ...). Our search view handles both normal and advanced search so it's a big tangled mess.

In the glorious future, wiki documents and support forum questions will comprise the "critical" group, will be in a "critical" index, will require the two-step commit stuff and our promise to users is that it will always be searchable even when we're deploying.

Everything else (including contributor forums) will be in another index where we can do whatever with it including deleting and reindexing everything in it. We won't require two-step commits with the things in this index.

Given that, I think we can have two indexes: one for critical stuff and one for whatevs stuff. We'll never want to search across these two indexes with the normal search. We really need to split out the normal search from advanced search, but that's a project for a new day.

We might want to search across indexes for advanced search (maybe something like, "show me everthing about the flash plugin"). That'd be fine since it's advanced search and we can be more lenient with our promises on performance.

It's possible I'm just saying the same thing again, but I figured I'd say it here in case it clarified anything. Also, this is what I think the plan is--it's possible I'm not aware of additional requirements that might require a different plan.