Re: How the backend knows it's being searched by syncprov?

[Howard Chu <hyc@symas.com>]

Pierangelo Masarati wrote:

> Howard Chu wrote:
>
> > Pierangelo Masarati wrote:
> >
> > > hyc@OpenLDAP.org wrote:
> > >
> > > > Update of /repo/OpenLDAP/pkg/ldap/servers/slapd/overlays
> > > >
> > > > Modified Files:
> > > >     syncprov.c  1.24 -> 1.25
> > > >  
> > > Howard,
> > >
> > > to use syncprov on top of back-sql, I need the backend to know it's 
> > > being searched for sync replication purposes when filtering for 
> > > CSN.  To this end, I added a function slap_find_control_id() that 
> > > returns the cid for a given control oid; then, to determine if a 
> > > search is performed for syncrepl purposes, I'd use
> > >
> > >        slap_find_control_id( LDAP_CONTROL_SYNC, &sync_cid );
> > >
> > > to grab the control's cid at initialization and, when requested to 
> > > filter for CSN, I'd test (op->o_controls[sync_cid]).
> > > sync_cid could be a back-sql wide static variable, initialized to -1 
> > > and grabbed, for instance, at bi_open(); or it could
> > > even be global scoped, in case other backends need to be 
> > > syncrepl-aware.
> > >
> > > Do you think this is correct?
> > >
> > > Ciao, Ando.
> >
> >
> >
> > Yes, thanks. I meant to add a function like this already but forgot.
>
>
> If you have one, go ahead.  Otherwise I'll commit mine

OK, done.

> > If we really need global knowledge of this control 
>
>
> back-sql has because it needs to generate appropriate entryCSN values 
> if searched for syncrepl purposes.  At the moment I don't see the need 
> for any other piece of code.

The entryCSN values are pretty much equivalent to modifyTimestamp. But 
how can you generate these values on the fly?

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