CODEWITHSUNDEEP
node.jsmongodbmongoose
Colin
Colin

Reputation: 1855

Mongoose: What can I assume about my data in the event of an error

Say I'm doing a single-collection, multi-document operation through Mongoose such as

// all my_model doc's have flag==false here
my_model.update({flag:false}, {flag:true}, {multi:true}, function(err) {
    if (err) {
         // what can I assume here?
    }
});

What can I say about my my_model documents in the event of an error? Will some have flag == true? Or is it an atomic operation in the sense that if there is an error, none of the updates will occur?

Is this behavior consistent amongst other multi-document operations with a single collection (ex remove()) ? Is this the price I pay for non-ACIDity ?

edit: From the mongodb docs:

The modification of a single document is always atomic, even if the write operation modifies multiple sub-documents within that document. For write operations that modify multiple documents, the operation as a whole is not atomic, and other operations may interleave.

Since other operations may interleave, I can only assume then that in the event of an error, the data would be in a transtional state, with some docs updated and others not.

Upvotes: 1

Views: 65

Answers (1)

Amalia
Amalia

Reputation: 936

Your intuition is correct. If there is an error during a multi-document update, you may have a situation in which some of the documents have flag == true and others have flag == false.

Upvotes: 1

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