System Collections

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    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

      Stores the schema version of the user credential documents.

    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 4.2Starting 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 4.2Starting 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 .system.profile collection stores database profiling information. For information on profiling, see Database Profiling.

    • <database>.system.``js

      The .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 .system.views collection contains information about each view in the database.

      参见

    原文 - System Collections