More efficient way to represent local+remote views?

[Kartik Subbarao <subbarao@computer.org>]

I'm currently using the following configuration for an 
application-specific LDAP directory to present a unified view of its 
local data (ou=localapp) and remote data (ou=people), all under 
dc=example,dc=com:

database hdb
suffix ou=localapp,dc=example,dc=com
# ...

database meta
suffix dc=example,dc=com
uri ldapi:///ou=localapp,dc=example,dc=com
uri ldap://remoteldap.example.com/ou=people,dc=example,dc=com

The idea being that clients of this directory can simply set the base DN 
to dc=example,dc=com without needing to know which parts are local and 
which parts are pulled in remotely.

My understanding is that this approach incurs some overhead in going 
through the ldapi interface for each operation that ends up being 
performed on the local backend. Is it possible to eliminate that 
overhead through an alternate approach? I looked at back_relay, but 
couldn't get it to do what I wanted. I don't want to rewrite any of the 
suffixes -- I just want it to do exactly as above in the back-meta 
configuration, but replace "ldapi:///" with "internal-backend-api:///", 
as mentioned in this part of the back-relay docs: "back-relay bypasses 
the real database frontend operations by short-circuiting operations 
through the internal backend API".

Thanks,

	-Kartik