I'm migrating a very simple mongo DB (couple 100 entries) to Azure Cosmos DB. My app is based on node-js so I'm using mongoose as a mapper. Before it was really simple, define schema, query collection, finished.
Now when setting up a collection in cosmos db, I was asked about partion key and shard key. The first one I could ignore, but the last one was required. Quickly reading-up on that topic and understanding it was kind of partioning (again, which I do not need and want), I just chose _id as shard key.
Of course something does not work.
While find queries work just fine. Updating or insert records fail, below is the error:
MongoError: query in command must target a single shard key
Cosmos db (with the mongo API) was advertised to me as a drop-in replacement. Which clearly is not the case because I never needed to worry about such things in mongo, especially for such a small scale app/db.
So, can I disable sharding somehow? Alternatively, how can I define shard key and not worry about it at all going forward?
Cheers
1.can I disable sharding somehow?
Based on the statements in Mongo official document,it can't be implemented.
MongoDB provides no method to deactivate sharding for a collection after calling shardCollection. Additionally, after shardCollection, you cannot change shard keys or modify the value of any field used in your shard key index.
So,you can't deactivate or disable the shard key.
2.Alternatively, how can I define shard key and not worry about it at all going forward?
According to this link,you could set the shard key option in Schemas when you use insert/update operation on your collection.
new Schema({ .. }, { shardKey: { tag: 1, name: 1 }})
Please note that Mongoose does not send the shardcollection command for you. You must configure your shards yourself.
BTW, set _id as shard key might not be a appropriate decision. You could find some advices about choosing shard key from here.If you want to change the shard key or just remove the shard key,please refer to this case:How to change the shard key