Structure Limited Field Document For Free

MongoDB rounds the size of all capped collections up to the nearest integer multiple of 256, in bytes.

There isn't a prescriptive maximum number of fields per document, but you should consider the relationships of fields in the same document and ensure that your data model efficiently supports your common use cases and indexing requirements.

MongoDB is a NoSQL Server in which data is stored in BSON (Binary JSON) documents and each document is essentially built on a key-value pair structure. As MongoDB easily stores schemaless data, make it appropriate for capturing data whose structure is not known.

A record in MongoDB is a document, which is a data structure composed of field and value pairs. MongoDB documents are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents.

Summarizing all the experiments: Mongo Atlas can easily cope with updating records under 1 million. Even updateMany will succeed in minutes. But be aware of the short spike in CPU usage to about 100%.

Document Size Limit The maximum BSON document size is 16 megabytes. The maximum document size helps ensure that a single document cannot use excessive amount of RAM or, during transmission, excessive amount of bandwidth. To store documents larger than the maximum size, MongoDB provides the GridFS API.

Max size of documents in MongoDB is 16 MB. If we want to store documents that are larger in size than 16 MB then we have to use GridFS in MongoDB. GridFS is dividing single documents into a number of chunks file, each chunk size is 256 KB.

_id is the primary key on elements in a collection; with it, records can be differentiated by default. _id is automatically indexed. Lookups specifying { _id: <someval> } refer to the _id index as their guide. Users can also override _id to something other than an ObjectID data type, if desired.