Have you ever got stuck with MongoDB error invalid object id length? Here’s a quick fix.

MongoDB errors are common and difficult to troubleshoot. This error mainly occurs due to variations in the ObjectId length requirements.

At Bobcares, we often receive requests to fix MongoDB error as part of our Server Management Services.

Today, let’s have a deep look at this error and its suitable fix.

What does “MongoDB error invalid object id length” indicate?

A unique Identifier helps to address, access and interact with a single entity within the system.

For instance, the username or UserID provided to the new users when registering for a website is the best example for UIDs. These UIDs are useful for security and log purposes which differentiate the user from other users.

ObjectID is the default UID used by MongoDB. Usually, this is a 12-byte binary value, represented as a 24 character hex string.

These ObjectId’s helps to generate UIDs in a distributed system.

But, when the ObjectID length is not 24 characters, it throws the error “MongoDB error invalid object id length”.

How to fix this easily?

Recently, one of our customers approached us with a MongoDB error. He tried to update the datatype string to ObjectId.

Half of the data has been converted to ObjectId but rest of them failed with the error:

Invalid ObjectID length

He used the following query for the conversion,

db.booking.find({user: {$exists:true}}).forEach( function(x) {
    x.user = ObjectId(x.user);
    db.booking.update({_id: x._id}, {$set: {user: x.user}});
});

Our Support Engineers checked and found errors with the ObjectId length. This is because some data among them does not meet the length requirement of the ObjectId.

We easily fixed this error by adding a where clause to the customer’s query as follows.

find({ user: { $exists: true }, $where: 'this.user.length === 24' })

This resolved the error effectively.

[Need more assistance to fix this error?- We’re available 24/7 to help you.]

Conclusion

In short, MongoDB error invalid ObjectId length error occurs when the data does not satisfy the length requirement of ObjectId. In today’s write-up, we saw this error in detail and also discussed how our Support Engineers fix it for our customers.