Description of problem: This could also be a release note I suppose. Basically this is just an overall improvement to the algorithms used to generate memberof attributes. Design Doc: http://www.port389.org/docs/389ds/design/memberof-scalability.html
Slight reorg of the RN text.
The release note of this 389-ds-base enhancement has been published in the RHEL 7.4 beta release notes: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7-Beta/html/7.4_Release_Notes/index.html