Reference >
System Collections

System Collections¶

On this page

Synopsis
Collections

Synopsis¶

MongoDB stores system information in collections that use the <database>.system.* namespace, which MongoDB reserves for internal use. Do not create collections that begin with system.

MongoDB also stores some additional instance-local metadata in the local database, specifically for replication purposes and in the config database for sessions information.

Collections¶

System collections include these collections stored in the admin database:

admin.system.roles¶: The admin.system.roles collection stores custom roles that administrators create and assign to users to provide access to specific resources.

admin.system.users¶: The admin.system.users collection stores the user’s authentication credentials as well as any roles assigned to the user. Users may define authorization roles in the admin.system.roles collection.

admin.system.version¶: The admin.system.version collection stores metadata to suport internal operations. Do not modify this collection unless specifically instructed to in this documentation or by a MongoDB support engineer.

System collections include these collections stored in the config database:

config.system.indexBuilds¶: New in version 4.4.

The indexBuilds collection stores information related to in-progress index builds.

System collections also include these collections stored directly in each database:

<database>.system.namespaces¶: Removed in 4.2

Starting in MongoDB 4.2, <database>.system.namespaces has been removed (access to the collection has been deprecated since 3.0). To list the collections in a database, use the listCollections command instead.

<database>.system.indexes¶: Removed in 4.2

Starting in MongoDB 4.2, <database>.system.indexes has been removed (access to the collection has been deprecated since 3.0). To list the inndexes, use the listIndexes command instead.

<database>.system.profile¶: The <database>.system.profile collection stores database profiling information. For information on profiling, see Database Profiling.

<database>.system.js¶: The <database>.system.js collection holds special JavaScript code for use in server side JavaScript. See Store a JavaScript Function on the Server for more information.

<database>.system.views¶: The <database>.system.views collection contains information about each view in the database.

← MongoDB Limits and Thresholds Connection String URI Format →