My host shut down my site today and told me this:
WordPress starts becoming inefficient at handling the number of posts somewhere between 1500 and 2500 posts, at over about 5000-6000 comments, and over around 7000 tags, give or take a little depending on plugin configuration. Once those numbers are doubled, it becomes exceedingly inefficient, performing very poorly and using a lot of cpu resources to process the results coming back from mysql.
Anybody else run into this and have any suggestions on what to do (other than deleting posts and comments)?
I might consider switching hosts, but if this is going to be a problem everywhere I go, what's the point?