Re: Issue in syncprov findcsn code

[Rein Tollevik <rein@OpenLDAP.org>]

Pierangelo Masarati wrote:

> Not sure this is a bug, but I'm curious... I hit this while checking for 
> ITS#5661.  The code below is from HEAD's syncprov.c:613 (not changed 
> recently; pardon any unintended line wrapping):

[code and discussion removed]

> - make syncprov_findcsn() search the newest contextCSN instead of the 
> one with its SID

Only looking for contextCSN values with sid matching the serverID was 
introduced in revision 1.240 to fix ITS#5537.

> - initialize slapd_serverID with some SID_UNDEFINED in order to take the 
> action above only when SID is not defined

I agree, although I would prefer to take it one step further and reserve 
serverID==0 for the tools case.  In ITS#5536 I tried to distinguish 
between a defaulted and configured serverID==0, but it didn't quite slip 
through and was closed without being properly fixed.  It should probably 
be reopened.

Btw, the ITS#5675 fix to syncrepl.c improves the contextCSN propagation 
from syncrepl to syncprov, but the csn queue isn't really suitable for 
that.  Syncrepl may update more than one contextCSN value at the same 
time, but the queue can only pass one around.  I'm currently testing a 
patch that fixes the contextCSN propagation problems we have seen, it 
should fix this as well.

Rein