Just to chime in with what's been good advice and discussion so far.

Over 100k IS top of field right now in a number of markets. It's basically max of market if you don't have a name.

I personally have a different opinion though of dev duties, and understanding page splits and how the storage mechanism works is one of them. What usually happens is after the fact the DBAs need to get involved because in usage scenarios don't match up with original design, but the developers need to have a solid understanding so those are 'one-off' repairs, not general continuous maintenance for the DBAs.

I wouldn't worry about it too much. As mentioned, noone can know everything. Let them know what you know, and worst case scenario just say "No, haven't been involved deeply enough in that yet, but I could research it." This is definately one of those fields that the more you learn the more you realize you need to learn.

Speaking of, I have to go try to wrap my head around NUMA. Again. Argh. Everytime I think I've got it... I don't got it. 🙂

Don't feel bad, we've all got weak spots. Mine is on the administration side though, I'm primarily a developer.