Role CSS & JS Aggregation

Drupal's CSS & JS aggregation can cause database deadlock in the variable table under heavy load, this will bring your site to its knees.

This module allows you to disable aggregation for any user with-out a specific role. The idea being that after a release you can serve un-aggregated css and js files until you warm the aggregation cache with a tiny fraction of your normal traffic levels, avoiding the row contention issues that lead to deadlock.

If you're in the middle of aggregation "inspired" downtime you can bring your site back to life with drush vset role_aggregation_enabled TRUE assuming you've got the module installed already.