This shall speed up small updates to big signed zone.
The previous procedure is:
- recreate all the NSEC(3) records in the zone
- compare to the existing NSEC(3) records, making a diff
- sign this diff
The new procedure is:
- recreate only NSEC(3) records (neighbouring to) records mentioned in the changeset
- sign the changed records
The observed total speed-up of a little zone update to a huge signed zone was around 15%, but there are also other problems not related to NSEC(3) chain reconstruction.
Fixes #119 (closed)