MongoException: Index with name: code already exists with different options
mongodb,spring-data-mongodb,mongodb-java,mongodb-indexes
You already have an index on that collection with the same name, but with a different definition. My guess is that your current code index is non-unique try: db.Term.getIndexes() If this is indeed the case (you have a non-unique index over code field), issue: db.Term.dropIndex("code_1") (replace with the code field...
MongoDB - What would the best Shard Key be for storing Email Pixel Tracking data
mongodb,sharding,mongodb-indexes
First of all, I would caution you not to jump into sharding right away. With your data volume, you should be able to have a single replica set handle your traffic. The real trigger point for sharding is when the working set becomes larger than is reasonable for the RAM...
Why MongoDB doesn't uses Index Intersection?
mongodb,indexing,database-indexes,mongodb-indexes
There are some details about the index selection in the SERVER-3071 JIRA issue but I cannot say if all is still relevant for 3.0. Anyway: MongoDB 3.0.2 seems not consider index interaction for range query. But it will for point intervals: > db.orders.find( { item: {$eq : "abc123"}, qty: {...
MongoDB Indexing and Projection
Does indexing helps in projection? I believe the only time it will really help (defined by performance etc) is if the query is "covered": http://docs.mongodb.org/manual/tutorial/create-indexes-to-support-queries/ So for example, if you wanted to query on {d:1, e:2} and get back {_id, t, e}, you would do: db.t.ensureIndex({d:1 , e:1, _id:1,...