LDAP caching problem

[buestad]

I tried to enable LDAP caching to speed up the user interface since our system has a huge userlist.

CacheEnabled=true
CacheFile=./data/ldap.cache.json

When I click Users -> List, no users are listed.

I tried to change the path to the CacheFile to absolute but it did not work

CacheFile=/opt/svnadmin/data/ldap.cache.json

I would assume that if the ldap.cache.json file does not exist it will be created, but it does not.
I then searched the php source code for CacheEnabled and the only place it is used looks like it does reading from the .json file.

How do I get the cache file created?