Adam Lee

After further investigation, I’ve fixed all the issues described above. If anyone else has similar problems, here’s what I did to fix them:

1. Disable the built-in cron module. At least for me, it was hogging the CPU and causing repeated errors as described above. You can fix this by commenting out the call to spawn_cron() around line 135 of wp-includes/cron.php.

2. In wp-settings.php, there’s use of the HTTP variables $_SERVER[‘SCRIPT_NAME’] and $_SERVER[“REQUEST_URI”] without checking to see if they’re defined. My version of Apache doesn’t define them, causing errors every time a page was loaded. Again, I commented out the code that makes reference to those variables.

3. The most significant change, the one I described above, is the call to wp_cache_postload() around line 380 of wp-settings.php. Every invocation of this function was taking between five and ten seconds, sometimes more. I believe this is used by WP’s built-in object cache, which I wasn’t even using. I took out this call and performance went way up.