Load pack header length and 15 header entries with single backend
request. This eliminates separate header Load() request for most pack
files and significantly improves index.New() performance.
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
Use result of single repository.List() to find both missing and
orphaned data packs. For 500GB repository this eliminates ~100K
repository.Test() calls and improves check time by >30M in my
environment (~45min before this change and ~7min after).
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>