Only columns wich are being indexed should trigger the ActsAsXapianJob on update/save

Image you have a model where 'title' and 'body' are being indexed. And you have another column called 'counter'. The counter increments each time the page shows a model. This would trigger the update_index mark on the ActsAsXapianJob table every time when the model is being viewed.

Suggestion:

• Update index only if the changed columns match the indexed columns
• Handle the following edge case: You're indexing a virtual column, something like: def full_name "#{first_name} #{last_name}" end You should be able to specify update_triggers => [:first_name, :last_name]. If one of the update_triggers matches the changed columns an mark for index-update can be created.