We have a project underway that requires the import of ~6 million users into Drupal (Core 7x) that have many (150K+) case-insensitive duplicate usernames. (ex: John,john,jOhn,JOHN). Importing these users with existing case and allowing them to log-in thereafter (case-sensitive) has been deemed mission-critical by stakeholders, and is a must-include feature. To facilitate this, I’ve changed the data type on the users table to VARBINARY from VARCHAR, which allows duplicate usernames with different case, and imported all users successfully.
After making this change, the problem now is that logging in takes a very long time (9-14 seconds) under no server load. I’m wondering if there are any ways to speed this up, and/or make any changes necessary that can significantly improve performance?
Index on the user table does include name. Picture attached.
