I'm not terribly familiar with bugzilla as a product, but while using it on mozilla.org I've noticed what appears to be a significant inefficiency in the way it processes bugs. Suppose bug A depends on bug B. Suppose now I add a comment and cc myself to bug B (or just add a comment). Both of these are extremely frequent use cases in my experience, and therefore worth optimizing for. Now, bugzilla happily goes and processes bug B, sending email to everyone on B's cc list etc. So far so good. But then it *also* goes and spends what appears to be a significant amount of time looking at the CC list for bug A before deciding not to send email to anyone at all. This is especially pronounced if the bug in question has lots of dependencies - it can take almost a minute for bugzilla to finish deciding to do nothing with all these bugs. As far as I know, there are *no* circumstances under which anyone attached to bug A might see a comment or CC change to bug B. So if bugzilla simply noticed that those were the only two fields changed, it could skip the whole "checking for dependency changes on..." step and probably reduce server load quite a bit. There are probably other fields that will never trigger a notification on dependent bugs, but even just optimizing out comment-and-cc-only changes would probably make a huge difference to server load. Of course, if I'm wrong and there *is* a way that somebody might get notified of comment or cc changes in a dependent bug, then this should be WONTFIXed.

*** This bug has been marked as a duplicate of 71794 ***

*** Bug 140155 has been marked as a duplicate of this bug. ***