group_mapping.ldb and 3.0.25

[tridge at samba.org]

Jerry,

In previous discussions of ldb in Samba3 I was told that we should
start small, with just one db, to see how it goes. That seemed like
a quite sensible approach. What has changed?

 > The ldb code should of course stay in SAMBA_3_0, but I
 > am reverting group_mapping to use the tdb API in order
 > to make it easier to swap between the two branches for
 > now.

Perhaps we should revisit the decision to not have a configuration
option? I had proposed a smb.conf option to choose between the tdb and
ldb backends for group_mapping. To support that, I left the old tdb
code in groupdb/mapping_tdb.c and made the APIs exactly compatible.

If we put in an option, then that would allow us to try out ldb in
production Samba code, while still making it easy to swap between
releases. 

What I would like to see is every long lived database converted from
tdb to ldb. Having long lived databases in a format that cannot be
sanely edited by an administrator is a bad idea, and the only method
we currently have of achieving that is to use ldb. 

Cheers, Tridge