are your users not posting? Once a post is made (anywhere) it should update the postcounts (for all posts).
The caching mechanism logs when someone accesses a post, and stores it in a 'memory' table, which is completely temporary; when a post is made, it merges all content of the temporary table with the post table.
Before this caching mechanism was in place, there was major corruption of the posts table, so in order to save content in the db from being corrupted, this was added in place.
So long as users make posts, the tables should be updated automatically.
