Problem Using Chain Overlay, unable to figure out dontusecopy control to fix it

[Andy Dorman <adorman@ironicdesign.com>]

- Debian OpenLDAP 2.4.39 using back_mdb

- delta-syncrepl master->multiple slaves (lightning fast and has worked 
great for many years)

- the client running on each slave and causing the problem is Horde 
using the php-ldap client (PHP 5.6).

Horde is configured to use the slave/localhost LDAP replica and we are 
hoping to use updateref and chain overlay to write to the master and 
read from the localhost slave.

Our slapd.conf global config has:

...
moduleload            back_ldap
overlay               chain
chain-uri             ldap://ldap.ironicdesign.com/

chain-idassert-bind   bindmethod="simple"
                      binddn="root dn"
                      credentials=<root pwd>
                      mode="self"
chain-return-error    TRUE
...

And after the syncrepl setup, the last line of slapd.conf defines updateref.

...
updateref     ldap://ldap.ironicdesign.com/


So, the problem comes when we add an address book contact to be stored 
in LDAP.   The contact is written successfully to the LDAP master, but 
then Horde/php-ldap tries to get/read the new contact and of course it 
is not on our localhost slave yet, so the "get" fails.

I noted in the OpenLDAP docs, "12.3.4. Read-Back of Chained 
Modifications", where it discusses using the "dontusecopy" control in 
the client to prevent this problem, but I can find no reference to 
setting this "dontusecopy" control anywhere in the PHP-ldap client or 
any other client for that matter.

Has anyone ever used the "dontusecopy" control and if so, would you mind 
terribly telling us how/where you used it?

Thanks for any insights.

--
Andy Dorman