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• Definition
• Output
• Examples

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:

copy

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 field:

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.

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.

Examples

db.adminCommand( { listDatabases: 1 } )

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

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

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

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

{
  "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
}