ldap attributes - performance problem?

Hi,

I'm thinking about solution to following problem: authorization to directories on our file server (accessed by webdav). Is it a performance issue to build solution on following pattern?

part of user's ldif ... uid=someone allow_dir: directory1 allow_dir: directory2 allow_dir: directory3 allow_dir: directory4

and then just htaccess directives in apache for every of these directories :)

it could happen that someone would have e.g. 50 of these attributes...would it be a problem?

Thanks for advice and advanced opinion :) Radim