CODEWITHSUNDEEP
mongodbatomic
yangbinnnn
yangbinnnn

Reputation: 79

About Mongodb: Atomic Get and Set

I'm a Mongodb beginner, I have a document like this:

{
    "_id": "abc",
    "names": {
        "1" : "name1",
        "2" : "name2",
        "3" : "name3"
    }
}

I want to use multithread add 'name4', 'name5', 'nameX'... to "names"

My way:

I know this is not atomic -_-!! so My question is How To Make It Atomic?

My another way: add a 'version' field to document, when Get the results, record the 'version', then Set the 'names' with the 'version' like :

update_one({"_id": "abc", "version": currentVersion}, {$set: {"names": newNames}})

If it does not match the 'version', the update failed, new 'nameN' will not add to the document. I want it to success any time.

Can someone help me? thanks

Upvotes: 1

Views: 338

Answers (1)

Luis Filipe
Luis Filipe

Reputation: 8718

MongoDB only guarantees transaction on a document-level.

For your requirements you must guarantee the atomicity at the application-level using thread synchronization.

Upvotes: 1

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