[SAMBA3] using LDAP DirSync Controls in winbindd

[tridge at tridgell.net]

Guenther,

 > Yes, I was thinking already about to register an async change notify
 > control on the highestCommitedUsn, and then only requery the dc upon
 > change instead of asking the dc whenever the winbind cache time has
 > expired.

The disadvantage of this is that in a really large domain you'll find
that the highestCommitedUsn changes about once a second (you can tell
just by looking at the current highestCommitedUsn and divide it over
how long the machine has been installed).

The change notify control could still be really good for smaller
domains, but I suspect on really big domains it will be triggering
constantly.

Cheers, Tridge