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Oplog Access

The oplog (operations log) is a special capped collection that keeps a rolling record of all operations that modify the data stored in your databases.

Atlas deployments of size M10 and greater can access the oplog.

Add a User with Oplog Access

To access the oplog, a database user must have read access on the local database. To create a user with read access on local:

1. In the Security section of the left navigation, click Database Access.
2. Click the MongoDB Users tab.
3. Click plus icon Add New User and enter a user name such as oploguser.
4. Click Add Default Privileges and select the read role and the local database. This restricts the user to read operations on the local database.
5. Enter a password and click Add User.

Access the Oplog

1. Connect to your cluster with the mongo shell, using the credentials of the new database user with access to the local database.

2. Switch to the local database.

   copy

   > use local
   

3. The oplog collection is named oplog.rs. Database write operations are recorded in date order, with a timestamp field and a wall clock field.

   The timestamp field contains an integer with seconds since epoch.

Note

• To increase the size of an oplog for a cluster, see Set Oplog Size.
• You cannot use the MongoDB command replSetResizeOplog to resize the oplog.

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