ATOMICally update multiple documents AND return them

Question

In MongoDB, I'm looking for a way to ATOMICally update multiple documents and return all of the updated documents in a single call.

We can do all of the following in MongoDB:

• Atomically update one document and return the updated document: findAndModify or findOneAndUpdate
• Atomically update multiple documents: update(...{multi: true} or updateMany
• Query and return multiple documents: find

I haven't fond a way to update multiple documents and return them all in one call. Is there a way? I'm using Mongoose as the querying package.

Answer 1

Atomically update multiple documents: update(...{multi: true} or updateMany

Unfourtantely that is false:

In MongoDB, write operations, e.g. db.collection.update(), db.collection.findAndModify(), db.collection.remove(), are atomic on the level of a single document.

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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.

However, you can simulate a transaction to atomically update multiple documents by "using a two-phase commit approach" which is described in detail there.

You may also look at the $isolated operator, which "prevents a write operation that affects multiple documents from yielding to other reads or writes once the first document is written" but it "does not provide “all-or-nothing” atomicity for write operations"

As a summary, it is not possible at mongodb level (nor the driver), but you can simulate it at your application level therefore return what you need.