I recently updated my blog theme to use P2. P2 is a free Wordpress theme that gives your site more of a Tumblr / Twitter style look.

In general, I liked it. However, I noticed that the performance really sucked. Digging in deeper it turns out the culprit is the P2 variable “mentionData.” I presume it is used to allow the mention feature to work. What it does is preload all of the user profile data onto the page. ┬áThis can be bad news for a Wordpress instance with a lot of users.

I had over 700 users on the site (that was another problem that I rectified), on each page load it P2 will fill in the mentionData variable with all 700+ account holders.

I’ve since deleted the offending users and my performance is great again. I don’t know enough about the theme to want to dive in and take a look at it. Hopefully the guys at Automattic can fix this.