adding branch= to the waterfall is expensive

[warner]

I added a max_search= to the IBuilderStatus.generateFinishedBuilds method, to limit how many builds are searched when constructing the one_line_per_build and one_box_per_builder pages, but the eventGenerator() method used by the waterfall has no such limit. As a result, actually using the new branch= argument on the waterfall page is very expensive, as any Builder which has never built that branch will cause eventGenerator() to run through its entire history, pulling each build off disk to check the branch name.

The long-term fix for this is to use a database for status information which can get us this information faster. The short-term fix (after 0.7.6, unfortunately) is to add a similar max_seach= argument to eventGenerator. It's too complex to add today, though.

[warner]

No progress made on this yet, bumping to 0.7.8

[dustin]

Waterfall is going to be removed/replaced.