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listDatabases

Definition

listDatabases

The listDatabases command provides a list of all existing databases along with basic statistics about them. The listDatabases must run against the admin database, as in the following example:

db.adminCommand( { listDatabases: 1 } )

The value (e.g. 1) does not affect the output of the command.

The listDatabases command can take the following optional fields:

Field Type Description
filter document

Optional. A query predicate that determines which databases are listed.

You can specify a condition on any of the fields in the output of listDatabases:

  • name
  • sizeOnDisk
  • empty
  • shards

New in version 3.6.

nameOnly boolean

Optional. A flag to indicate whether the command should return just the database names, or return both database names and size information.

Returning size information requires locking each database one at a time, while returning only names does not require locking any database.

The default value is false, so listDatabases returns the name and size information of each database.

New in version 3.6.

authorizedDatabases boolean

Optional. A flag that determines which databases are returned based on the user privileges when access control is enabled.

  • If authorizedDatabases is unspecified, and
    • If the user has listDatabases action on the cluster resource, listDatabases command returns all databases.
    • If the user does not have listDatabases action on the cluster, listDatabases command returns only the databases for which the user has the find action on the database resource (and not the collection resource).
  • If authorizedDatabases is true, listDatabases command returns only the databases for which the user has the find action on the database resource (and not the collection resource).
  • If authorizedDatabases is false, and

For more information, see Behavior.

New in version 4.0.5.

Output

listDatabases returns a document that contains:

  • A field named databases whose value is an array of documents, one document for each database. Each document contains:
    • A name field with the database name.
    • A sizeOnDisk field with the total size of the database files on disk in bytes.
    • An empty field specifying whether the database has any data.
    • For sharded clusters, a shards field that includes the shard and the size in bytes of the database on disk for each shard.
  • A field named totalSize whose value is the sum of all the sizeOnDisk fields in bytes.

Behavior

When authentication is enabled:

  • For MongoDB 4.0.5+:
    The listDatabases command returns different values based on the privileges assigned to the user who executes the command and the authorizedDatabases command option:
    • If authorizedDatabases is unspecified, and
      • If the user has listDatabases action on the cluster resource, listDatabases command returns all databases.
      • If the user does not have listDatabases action on the cluster, listDatabases command returns only the databases for which the user has the find action on the database resource (and not the collection resource).
    • If authorizedDatabases is true, listDatabases command returns only the databases for which the user has the find action on the database resource (and not the collection resource).
    • If authorizedDatabases is false, and
  • For MongoDB 4.0.0-4.0.4:
    The listDatabases command returns different values based on the privileges assigned to the user who executes the command.
    • If the user has the listDatabases privilege action on the cluster, the listDatabases command returns a list of all existing databases.
    • If the user does not have the listDatabases privilege action on the cluster, the listDatabases command only returns a list of databases for which the user has the find action.

Examples

List Database Names and Sizes

Run listDatabases against the admin database:

db.adminCommand( { listDatabases: 1 } )

The following is an example of a listDatabases result:

{
   "databases" : [
      {
         "name" : "admin",
         "sizeOnDisk" : 83886080,
         "empty" : false
      },
      {
         "name" : "local",
         "sizeOnDisk" : 83886080,
         "empty" : false
      },
      {
         "name" : "test",
         "sizeOnDisk" : 83886080,
         "empty" : false
      }
   ],
   "totalSize" : 251658240,
   "ok" : 1
}

List Database Names Only

New in version 3.6.

Run listDatabases against the admin database. Specify the nameOnly: true option:

db.adminCommand( { listDatabases: 1, nameOnly: true} )

The following is an example of a listDatabases results when run with the nameOnly: true option:

{
   "databases" : [
      {
         "name" : "admin"
      },
      {
         "name" : "local"
      },
      {
         "name" : "test"
      }
   ],
   "ok" : 1
}

List Databases That Match the Filter

New in version 3.6.

Run listDatabases against the admin database. Specify the filter option to only list databases that match the specified filter criteria.

For example, the following specifies a filter such that listDatabases only returns information on databases whose name matches the specified regular expression:

db.adminCommand( { listDatabases: 1, filter: { "name": /^rep/ } } )

Sharded Clusters

When executed against a mongos instance, listDatabases:

  • adds a shards embedded document to each database’s summary document if nameOnly: false, and
  • excludes the local database.

Each element in the shards embedded document consists of a field whose key gives the name of a collection on that shard, and whose value represents the collection’s size in bytes.

The sizeOnDisk field represents the total size of all listed collections.

For example:

{
  "databases" : [
    {
      "name" : "admin",
      "sizeOnDisk" : 16384,
      "empty" : false,
      "shards" : {
        "config" : 16384
      }
    },
    {
      "name" : "config",
      "sizeOnDisk" : 176128,
      "empty" : false,
      "shards" : {
        "clients" : 28672,
        "patients" : 8192,
        "config" : 139264
      }
    },
    {
      "name" : "test",
      "sizeOnDisk" : 12288,
      "empty" : false,
      "shards" : {
        "clients" : 12288
      }
    }
  ],
  "totalSize" : 204800,
  "totalSizeMb" : 0,
  "ok" : 1
}