I have two Moodles that I manage - both running 2.6.1+ on Ubuntu 12.04 with Mysql
On one when I go the assignments> view grading it's very slow to load, upto a minute is some cases
With the other one clicking the view grading link causes Moodle to lock up completely - no one can login or move around the site. Restarting apache2 brings the site back to life. What's really odd here is that apachetop, mytop, htop and the mysql slow queries log don't show anything in particular happening when the site locks up.
Is someone able to give me some pointers on things I can look at top try and solve this please.