[Firebird-devel] Backup/restore vs ACLs

[Dmitry Y. <fir...@ya...>]

All,

Historically, we backup and restore security classes with names not 
starting with 'SQL'. Regular security classes are SQL-based and they're 
recreated at the commit (DFW) time, so there's really no sense in 
transporting them back and forth. So I suppose that backup/restore 
support is present for some kind of manually created security classes. 
However, I failed to find such things in QLI, maybe it presented in GDEF 
in the past days.

So, unless someone knows any good reason to see non-SQL security classes 
in our databases, I'd suggest to remove security classes from backups 
(avoid adding them to backup and skip them during restore).

Rationale is simple: changes in ACLs are unlikely to be backward 
compatible. If we bump ACL_version, the ACL transmitted from the newer 
engine will throw a bugcheck in the older engine. If we don't bump 
ACL_version, a bugcheck will be thrown anyway as soon as the older 
engine notices a new ACL item. And, unlike similar situation with BLR, 
new ACL item could appear (e.g. be created during restore) for the 
existing metadata objects in the newer engine. So I suggest to treat 
ACLs as a private part of the ODS and avoid migrating ACLs between 
different FB versions, including backup/restore.

Provided that ACLs *seem* to not being migrated now anyway, I don't 
foresee any compatibility issues. But I could be missing something.

Comments anyone?


Dmitry