Rein Tollevik wrote:
I've been trying to figure out why syncrepl used on a backend that is subordinate to a glue database with the syncprov overlay should save the contextCSN in the suffix of the glue database rather than the suffix of the backend where syncrepl is used. But all I come up with are reasons why this should not be the case. So, unless anyone can enlighten me as to what I'm missing, I suggest that this be changed.
The problem with the current design is that it makes it impossible to reliably replicate more than one subordinate db from the same remote server, as there are now race conditions where one of the subordinate backends could save an updated contextCSN value that is picked up by the other before it has finished its synchronization. An example of a configuration where more than one subordinate db replicated from the same server might be necessary is the central master described in my previous posting in http://www.openldap.org/lists/openldap-devel/200806/msg00041.html
There are only two supported modes of operation intended here. In one case, the glued databases each have their own syncprov overlay, and replication does not cross glue boundaries. In the other case, there is a single syncprov overlay for the entire glued tree, and the boundaries between glued DBs are ignored. In this config, all of the contextCSNs must be saved in the glue DB so that the single syncprov overlay can stay informed about any underlying changes.
-- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/
