Re: question about the meta backend

[Howard Chu <hyc@symas.com>]

Pierangelo Masarati wrote:

> > Can it be told to merge all of the objects
> > with the same dn
> > into one object containing the attributes of all?
> >    
> No.  In principle, you could design a layer that does this; the
> translucent overlay does something similar; the point is that to be able
> to do it consistently for distributed systems, all search results should
> be temporarily stored and merged until the very end before any results can
> be returned.  Another issue is that write operations would be very
> difficult, since back-meta should know how to split attributes and values
> among the targets.  Of course one can figure out many ways to do it, but
> it would get very implementation specific.
>  
We will soon be extending the translucent overlay to allow configuring a 
list of "local" attributes. This would allow more intelligent processing 
of e.g. search filters (currently a search is sent to the remote server 
unmodified; if the filter references attributes that are not known to 
the remote server, the filter usually results in Undefined.)

A similar approach could be taken in back-meta, where attribute 
affinities are defined for each target, with options to merge or replace 
on a per-attribute basis. This way you could designate that "writes to 
Attribute foo always go to target bar" and so on.

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