exclude_tree in wp_list_pages causes heavy CPU usage

[henry.jiang]

When using exclude_tree in wp_list_pages to exclude pages from the page menu bar, CPU usage jumps to 99.9%. In my example, I have 3000 pages who's parent is 13955 that I'm excluding from the menu bar by using exclude_tree in wp_list_pages.

This caused 99.9% CPU usage, and in a high traffic scenario, web server crashed unexpectedly. The piece of code responsible is in wp-include\post.php: &get_posts()

exclude_tree is being done after get_results() and update_page_cache(). This is the reason for the CPU spike.

A better way to implement exclude_tree should be before the call to get_results()

[scribu]

I think there have been some optimisations done in the upcoming WP 2.9 related to this.

Try updating to a nightly build and see if the problem persists.

[scribu]

Closing for lack of reporter feedback.