[Freeipa-devel] DNS zone serial number updates [#2554]

[Simo Sorce]

On Wed, 2012-04-18 at 10:04 -0400, Simo Sorce wrote:
> > We can compute maximal modifyTimestamp from all idnsRecord objects
> during 
> > initial query. Any change later in time will add only single
> attribute to 
> > transfer + max(currvalue, newvalue) operation. This way (with
> psearch) has 
> > reasonably small overhead, I think.
> 
> The problem is that max(currvalue, newvalue) is not useful.
> 
> 
Ah btw about this point I forgot about entryUSN which is a DS extension
we use in FreeIPA. with emtryUSn we can count on using max(curvalue,
newvalue) as entryUSN always increases monotonically even for replicated
entries independently of the timestamp they carry.
However you _cannot_ use entryUSN as an absolute value as it is a
per-server value and it can also be reset with a reinitialization.

But you can use it as a trigger for a serial increment.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York