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listDatabases

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  • Definition
  • Behavior
  • Examples
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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:

      • For MongoDB 4.0.6+, listDatabases command returns only the databases for which the user has privileges (including databases for which the user has privileges on specific collections).
      • For MongoDB 4.0.5, 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,

    • For MongoDB 4.0.6+, listDatabases command returns only the databases for which the user has privileges (including databases for which the user has privileges on specific collections).
    • For MongoDB 4.0.5, 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.

comment
any

Optional. A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations:

A comment can be any valid BSON type (string, integer, object, array, etc).

New in version 4.4.

When authentication is enabled:

Note

For mongosh connected to earlier versions of MongoDB deployment (e.g. 3.6.10),

  • If the user has listDatabases action on the cluster resource, show dbs returns all databases.
  • If the user does not have listDatabases action on the cluster resource, show dbs returns only the databases for which the user has privileges (including those databases for which the user has privileges on specific collections).

Starting in MongoDB 4.2, if the client that issued the listDatabases disconnects before the operation completes, MongoDB marks the listDatabases for termination (i.e. killOp on the operation).

Starting in MongoDB 4.4, to run on a replica set member, listDatabases operations require the member to be in PRIMARY or SECONDARY state. If the member is in another state, such as STARTUP2, the operation errors.

In previous versions, the operations can also be run when the member is in STARTUP2. However, the operations wait until the member transitions to RECOVERING.

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,
"totalSizeMb" : 251,
"ok" : 1
}

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
}

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/ } } )

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 and indexes.

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
}
Tip
See also:
listDatabases.databases

Type: Array

Array of documents, each containing information on a single database.

listDatabases.databases.name

Type: String

Name of the database.

listDatabases.databases.sizeOnDisk

Type: Integer

Total size of the database files on disk, expressed in bytes.

listDatabases.databases.empty

Type: Boolean

Specifies whether the database is empty.

listDatabases.databases.shards

Type: Document

Each element in the shards 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.

shards only appears in the output if nameOnly: false.

See Sharded Clusters for details.

listDatabases.totalSize

Type: Integer

Sum of all the sizeOnDisk fields in bytes.

listDatabases.totalSizeMb

Type: Integer

Sum of all the sizeOnDisk fields, expressed in megabytes.

listDatabases.ok

Type: Integer

Return value for the command. A value of 1 indicates success.

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