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Re: (ITS#4487) Problem with dereferencing aliases to remote DB with different suffix

On Wed, 2006-04-12 at 00:49 +0000, hyc@symas.com wrote:

> Irrelevant. Aliases are not the same as referrals. Aliases can only 
> point to other entries within the same database, you must use referrals 
> to point to something in a different database.

The question may not be pointless: amorphous stuff like back-meta, in
some cases could be used to mask the distribution of the database; in
those cases, clients might want to be able to dereference aliases under
the perception that the database is monolithic.

So, if the existence of the alias is the result of a write operated by a
client which was induced to believe that the database is monolithic, it
would be reasonable to have that alias treated appropriately by back-
meta; otherwise, it's just an indication of poor database
design/maintenance: LDAP does not prevent writing dangling aliases, and
one shouldn't rely on dangling aliases to work as incorrectly expected.

In fact, I'm facing a number of problems in making a distributed
database appear to clients as non-distributed.  Currently, aliases
cannot be distributed (and I don't think they'll ever be by back-meta)
since back-meta doesn't really try to hide the fact that the database is
actually distributed (except for allowing automatic referral chasing).

One of the problems I had to deal with is cross-database renaming; I
worked it around by copying the entry from the original to the new
database while renaming, using manageDIT to preserve operationals as
appropriate (and the whole operation is not ACID; I need to redesign it
using LDAP transactions, and there likely remain ACID issues related to
the commit sequence with the two databases).  This feature is not in
back-meta yet; will be merged in some time.  A similar feature could be
added to slapo-glue as well.


Ing. Pierangelo Masarati
Responsabile Open Solution
OpenLDAP Core Team

SysNet s.n.c.
Via Dossi, 8 - 27100 Pavia - ITALIA
Office:   +39.02.23998309          
Mobile:   +39.333.4963172
Email:    pierangelo.masarati@sys-net.it