CN must be indexed?

Working on the OpenLDAP backend for Samba4, I'm wondering if this is expected:

Is 'cn' a special attribute in the OpenLDAP code? It seems that the builtin schema definition (or something else) requires that the 'cn' attribute be indexed with

index cn eq

Otherwise, searches for cn=foo fail, where cn=foo* succeeds...

I'm using current CVS, and trying to have Samba4 automatically generate configuration files for OpenLDAP, possibly based on the (AD) schema-data we will load into the directory.

As such, knowing any (particularly other, similar) OpenLDAP-imposed constraints will be very useful, so that I can ensure these are met by the provision-backend script in Samba4.

Thanks,

Andrew Bartlett