How do you recognize 100,000 reports of the same bug but different manifestation ? What if it's an architectural issue (and many bugs are)? What if you are alre

How do you recognize 100,000 reports of the same bug but different manifestation ? What if it's an architectural issue (and many bugs are)? What if you are already working on a total re-write that's going to be released in 2 releases ? What do you do with bugs found internally ? Also remember that many bugs requires much more then changing a couple of lines of code, they require cross module changes and re-testing which can lead to more bugs.