How does ensureIndex work in mongoengine?

[Roy Smith]

If you add an index to a Document class's meta, when does that get executed?  Does it call ensureIndex() before every query?  Or just once when the class is first imported?  Or something else?

[Alice Bevan–McGregor]

On Saturday, January 28, 2012 10:36:48 AM UTC-5, Roy Smith wrote:

If you add an index to a Document class's meta, when does that get executed?  Does it call ensureIndex() before every query?  Or just once when the class is first imported?  Or something else?

+1 on this question.  I'm about to write a migration script to execute ensureIndex, but it'd be nice if this wasn't necessary.