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mongodbspring-datalockingbulkupdate
dstibbe
dstibbe

Reputation: 1697

Does mongodb lock between bulk groups?

Given a collection containing documents of the following format:

{ 
  name:String,
  members: [ { name:String, type: String } ]
}

Let's say I have a mongodb bulk operation, containing two operations:

The question is: will mongodb lock the documents in question between A and B? So that no modification to 'members' of the targeted documents can take place by other processes between A and B?

Upvotes: 0

Views: 1499

Answers (1)

kevinadi
kevinadi

Reputation: 13775

No it won't. By default, MongoDB operations will be atomic per document, and not within a group of documents (which is what a bulk operation is).

To quote from the Atomicity and Transactions page:

In MongoDB, a write operation is atomic on the level of a single document, even if the operation modifies multiple embedded documents within a single document.

Also:

When a single write operation (e.g. db.collection.updateMany()) modifies multiple documents, the modification of each document is atomic, but the operation as a whole is not atomic.

MongoDB 4.0, however, supports multi-document ACID transactions with some restrictions, such as it supports it only on replica sets, and the overall data in a transaction cannot exceed 16 MB.

Regarding Spring, MongoDB 4.0 transactions is supported in the Lovelace release (DATAMONGO-1920). There are examples in this blog post by Pivotal.

Upvotes: 1

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