What the live query plan doesn’t tell you about your query.
- That it’s being blocked
- What it’s waiting on
No seriously, nothing turns red or beeps or starts checking its watch, and there’s no Clippy asking you to hang on a moment. It just sits there.
And since the query hasn’t finished running yet, we don’t have any wait stats in the plan XML yet.
Assuming that’s fairly easy for Management Studio to get at the operator level—Erik does note that you can get this blocking information from DMVs at the session/query level—it’d be nice to add this information.