Mongodb: when to call ensureIndex?

Question

When should I call ensureIndex? Before inserting a single record, after inserting a single record, or before calling find()?

Regards,

Johnny

Answer 1

You only need to do this once. Example:

db.table.insert({foo: 'bar'});
var foo = db.table.findOne({foo: 'bar'}); // => delivered from FS, not RAM
db.table.ensureIndex({foo: 1});
var foo = db.table.findOne({foo: 'bar'}); // => delivered from RAM, not FS
db.table.insert({foo: 'foo'});
var foo = db.table.findOne({foo: 'foo'}); // => delivered from RAM, not FS