Does the updateMany() operation roll back updates if there is an error?

The updateMany() operation in MongoDB does not roll back updates if there is an error during the execution of the operation. When you perform an updateMany, MongoDB attempts to apply the updates to all matching documents in a single operation. If an error occurs while processing this operation, the changes that have been successfully applied prior to the error remain committed in the database. This behavior is part of MongoDB's design, where it opts for eventual consistency rather than an all-or-nothing approach, meaning that partial updates can occur.

In scenarios where atomicity is required for multiple write operations, developers need to consider using transactions with the capabilities of multi-document transactions introduced in newer versions of MongoDB. These transactions ensure that all operations either complete successfully together or none of them are applied, thereby offering a mechanism for rollback should any error occur.

Understanding this aspect of updateMany is crucial for managing how updates are applied in your MongoDB operations and ensuring proper data integrity when necessary.