cursor.batchSize()

Definition

cursor.batchSize(size)

Important

mongosh Method

This page documents a mongosh method. This is not the documentation for a language-specific driver, such as Node.js.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

Specifies the maximum number of documents within each batch returned in a query result. By default, the initial batch size is 101 documents and subsequent batches have a maximum size of 16 mebibytes (MiB). This option can enforce a smaller limit than 16 MiB, but not a larger one. If you set batchSize to a limit that results in batches larger than 16 MiB, this option has no effect and batchSize() uses the default batch size.

A batchSize of 0 means that the cursor is established, but no documents are returned in the first batch.

Note

If the batch size is too large, the cursor allocates more resources than it requires, which can negatively impact query performance. If the batch size is too small, the cursor requires more network round trips to retrieve the query results, which can negatively impact query performance.

Adjust batchSize to a value appropriate to your database, load, and application needs.

The batchSize() method takes the following field:

Field	Type	Description
size	integer	The maximum number of documents to return for a batch. The default initial batch size is 101 documents and subsequent batches have a maximum size of 16 mebibytes (MiB). This option can enforce a smaller limit than 16 MiB, but not a larger one. The default applies to drivers and Mongo Shell. For details, see Cursor Batches.

Compatibility

This method is available in deployments hosted in the following environments:

• MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

• MongoDB Enterprise: The subscription-based, self-managed version of MongoDB

• MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

Example

The following example sets batchSize for the results of a query (specifically, find()) to 10:

db.inventory.find().batchSize(10)

Learn More

• Cursor Batches

• cursor.next()

• getMore