For the query db.products.find( { key: “a” } ), which one is more performant? Given that field key is indexed in both cases, the complexity index search itself would be very similar. As the value of a would be hashed, and stored in the index tree. If we’re looking for the overal performance cost, the … Read more
Querying will certainly be a lot easier in the second case, where ‘groups’ is an array of sub-documents, each with an ‘id’ and a ‘name’. Mongo does not support “wildcard” queries, so if your documents were structured the first way and you wanted to find a sub-document with the value “hi”, but did not know … Read more
If you want raw access to the indexes, you can query the db.system.indexes collection: > db.system.indexes.find() To find the indexes for a specific collection, you can do: > db.collection.getIndexes() See this question.
You’re running into the 32MB limit on an in-memory sort: https://docs.mongodb.com/manual/reference/limits/#Sort-Operations Add an index to the sort field. That allows MongoDB to stream documents to you in sorted order, rather than attempting to load them all into memory on the server and sort them in memory before sending them to the client.
From the shell: db.test.getIndexes() For shell help you should try: help; db.help(); db.test.help();