Re: delta-syncrepl missing changes

[Francis Swasey <Frank.Swasey@uvm.edu>]

On 3/9/09 2:57 PM, Quanah Gibson-Mount wrote:
> --On Friday, March 06, 2009 7:30 AM -0500 Francis Swasey 
> <Frank.Swasey@uvm.edu> wrote:
>
> > This hypothesis has been confirmed with the modifications that didn't
> > make it to the replicas yesterday morning and this morning.
> >
> > Looks like the race conditions in accesslog/syncrepl that are being
> > worked on in the ITS's against 2.4 were present in the later 2.3 systems
> > as well.
>
> I'm not sure what race conditions you're referring to here.  Using 
> accesslog serializes writes, therefore you can't hit the race conditions 
> about updating the CSN that are being worked on in current RE24.
>
> I'll note that my 2.3.43 builds are actually a hybrid with some 2.4 
> code. I don't believe there's anything accesslog specific in it, but 
> there is some connection code reworking that is a part of it (the 
> lightweight dispatcher from 2.4, most notably).  I've yet to see this 
> with any of our deployments and some of them are quite large and 
> extremely busy.

To be specific, there are changes that make it into the master server, 
and the auditlog overlay logs them, but the accesslog overlay does NOT 
put them in the accesslog database, so they do not get sent to the 
replica servers.

It seems to be some kind of race condition.  I haven't figured out a way 
to reproduce the failure yet.

--
Frank Swasey                    | http://www.uvm.edu/~fcs
Sr Systems Administrator        | Always remember: You are UNIQUE,
University of Vermont           |    just like everyone else.
  "I am not young enough to know everything." - Oscar Wilde (1854-1900)