List of problems in pkgdb, which make it slow:
- In auto mode, the fix_cycles() still checks for cycles. However, it only outputs the results and does not fix them. Since the auto mode is usually called by portupgrade, this wastes time.
Solution: skip this stage in auto mode. Effect: reduced time from 1:44 to 0:30
- Even there is no changes, we still regenerate +REQUIRED_BY
Solution: if not changed, do not regenerate Effect: reduced time from 0:30 to 0:23
