Check Users database: Results Error

Warning: 4 entries in the core_acl_aro table without corresponding users table rows.

Following entries of user_usergroup_map table are missing in users table: user id=10 (aro_id=), user id=54 (aro_id=), user id=203 (aro_id=), user id=956 (aro_id=). This core_acl_aro entry with aro_id 0 should be removed, as it's not allowed.

What does this mean?

You have usergroups assigned to users that don't exist. It can be safely ignored, you can try removing them manually from _user_usergroup_map, or if CB provides a fix link you can try it.

When I go to tools it tells me it ran out of memory I have set the memory to 256M in the php.ini file and also in WHM(I have root access). I have about 20k of groups and this is just a small amount for testing purposes it will more likely be around 2 million when I am done.

There are 48 categories and inside each category there will be 50 groups and inside of them it can have 2000+ sub-groups.

You have 20,000 usergroups? I highly suggest against doing that. You're going to cause every ACL check in Joomla, CB, and any other extension to take forever. It flat out won't work if you expect to have 2 million. I suggest implementing some sort of other usage to determine usertype (CB field, CBSubs plans, etc..).

Can I PM you? I am looking for direction nothing more.

Please post all discussion here unless sharing sensitive data like login credentials (which aren't needed in this case).

Regarding your usage Joomla loads every usergroup at once. This mans if you have 2 million that's 2 million rows loaded and processed at once basically on every page load. This will kill your site. Even with highly powerful server it's going to be slow or crash constantly. This is just a limitation of Joomla based off how usergroups are implemented.

Perhaps GroupJive can be used to categories and group users together? Next release has major optimizations and will be able to easily handle 2 million groups for example. All queries in next release cap to a maximum of 1,000 rows to prevent performance issues.