During Initial sync we should record stats:

• Number of (oplog) update failures
• Number of out-of-band document queries (when an oplog failure occurs)
• Number of DB/Collections created/finished
• Elapsed time
• Number of errors
• Number of retries
• Number of times setting minvalid

This info would be very useful for monitoring and for diagnosing performance issues (like repeatedly having to query, on a new connection, for the most recent doc).