[{"collection":"collection","count":10,"content":{"_id":{"type":"string","minLength":3,"maxLength":10},"linkedListingID":{"type":"string","minLength":4,"maxLength":10}},"indexes":[{"name":"_id_linkedListingID","key":{"_id":1,"linkedListingID":1}}]}]

db.collection.find({$or:[{_id:"abc"},{linkedListingID:"bca"}]}).explain("executionStats")