Hmm, from reading the thread it does not appear to have been solved, at least not the underlying problems. What was solved was the removal of a couple of synchronous calls. The fact that there are slow queries on some profiles seems to have been caused by the fact that ANALYZE does not run for some people[1], and this does seem like it has been fixed yet. I should check this for my Firefox profile at work to see if old stats are the reason for it hanging.

So what needs to be fixed ,if I follow that thread, is the removal of all synchronous calls and some solution to either not have to run ANALYZE or run it more often.

1. https://bugzilla.mozilla.org/show_bug.cgi?id=686025#c89