How quickly are updates from the updateMany() operation visible?

Updates made using the updateMany() operation are visible as soon as they are performed due to MongoDB's default behavior of providing immediate consistency for write operations. This means that once an update is executed and acknowledged by the server, any subsequent read operation that occurs on the same primary node will reflect the updated data immediately.

The underlying architecture of MongoDB, particularly with its use of replica sets, allows for this immediate visibility because writes are first applied to the primary node before being replicated to secondaries. As long as you are reading from the primary or have a read preference that allows reading from the primary, the newly updated values will be available right after the operation completes.

This immediate consistency is particularly useful for applications that require real-time access to the most recent data updates, ensuring that users or processes querying the database can trust they are seeing the latest information. Thus, when using updateMany(), users can expect that their changes will be immediately reflected in future queries, offering a seamless experience in data handling.