Re: (ITS#6915) memberof+accesslog duplicate reqStart

[hyc@symas.com]

ebackes@symas.com wrote:
> The openldap-techincal traffic Michael mentioned is almost certainly the
same issue. In our case, yes this could have appeared as early as 2.4.23.
>
> What I'm seeing now is that formerly memberof functioned with accesslog in
> a
delta-syncrepl type environment by having each stage of replication (master,
hub, replica, etc) run the overlay to supply the changes. It seems like
originally only the group change went through and the overlay relied on
reqStart collisions to prevent its internal operations from reaching the
replication log.
>
> So: the recent change that exposed this was something that changed the
> order
these things are applied and sent to accesslog.
>
> Changing memberof again to reveal only the group changes should probably a
separate ITS, or perhaps a discussion (openldap-devel) on how we want it to
work. As-is, the fix in git master breaks compatibility with configurations
from prior releases.

The breakage seems to go back to ITS#6329.

The original design for memberOf was for the internal modifications to not be 
replicated. Instead, any replicas that wanted to maintain member information 
was expected to run an identical memberOf overlay configuration.

The fact that memberOf didn't update the entryCSN on its internal 
modifications was intentional. This design constraint was broken by the fix to 
ITS#6329. The patch for #6329 and any ripple effect from it needs to be reverted.

In general it's incorrect to replicate internal operations. The fanout from 
replicating every internal operation would be too large and the information 
content of what is being replicated is essentially nil. When the servers are 
configured identically they will maintain identical data by virtue of the 
overlays on each node performing the same internal operations in response to a 
given sequence of user operations.

> Emily Backes
> Symas - The LDAP Guys
> ebackes@symas.com
>
>
>
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/