Scalability of WPLMS

We are running into some scalability issues that we would like to address and see if there is a way to get around this. Currently we are having +- 900k rows in Usermeta, 2mln rows in postmeta, which is really slowing everything down. Offcourse all the normal things are done (no post revisions, orphaned is gone, unnecessary items removed). Database caching, page caching, everything is set up properly - and we use proper servers. Now due to the size of the database, we are walking into the following problem. Queries put on usermeta & postmeta are really slow at this moment. That is slowing the complete site down, which is not good for the speed of everything - not good for usability & conversions. We have done some research, and it looks like its due to a couple of reasons: In usermeta --> All the completed units are saved there. Resulting in 25% of the rows being made up of complete_unit items. For a table that is used a lot for queries this is really not something you want. In postmeta --> Several items are saved double, however it's unclear which we possibly could remove. Also, all the units & courses are saved in those tables. However, orders are saved there as well. This results in huge tables and data being stored in those tables, where a lot of queries are put on as well. On the site, there are many dynamic queries. For example requesting if a user is following a course and changing the button. This results in many queries being put on the server, which is not something really wanted. Suggested solutions: --> Decrease the amount of needed queries --> Create quicker queries --> Adding extra / more indexes to the database --> Separate WPLMS specific data and migrate to new tables (wp_courses, wp_coursemeta, wp_unit, wp_unitmeta, etc). --> Any other suggestions appreciated Now, we will not be able to do this currently ourselves - but this is something that is going to keep happening to everybody that grows. We are now at 20k users, 300 courses. However, that is growing rapidly (and it should be able to keep on growing). How can we make sure in the future that WPLMS is going to be ready to scale? If needed we're happy to pay for customizations or getting it ready. Happy to hear your thoughts on this, and discuss possible solutions!