CREATE ROLE

Defines a new database role (user or group).

Synopsis

  1. CREATE ROLE <name> [[WITH] <option> [ ... ]]

where option can be:

  1.       SUPERUSER | NOSUPERUSER
  2.     | CREATEDB | NOCREATEDB
  3.     | CREATEROLE | NOCREATEROLE
  4.     | CREATEUSER | NOCREATEUSER
  5.     | CREATEEXTTABLE | NOCREATEEXTTABLE 
  6.       [ ( <attribute>='<value>'[, ...] ) ]
  7.            where <attributes> and <value> are:
  8.            type='readable'|'writable'
  9.            protocol='gpfdist'|'http'
  10.     | INHERIT | NOINHERIT
  11.     | LOGIN | NOLOGIN
  12.     | REPLICATION | NOREPLICATION
  13.     | CONNECTION LIMIT <connlimit>
  14.     | [ ENCRYPTED | UNENCRYPTED ] PASSWORD '<password>'
  15.     | VALID UNTIL '<timestamp>' 
  16.     | IN ROLE <rolename> [, ...]
  17.     | ROLE <rolename> [, ...]
  18.     | ADMIN <rolename> [, ...]
  19.     | USER <rolename> [, ...]
  20.     | SYSID <uid> [, ...]
  21.     | RESOURCE QUEUE <queue_name>
  22.     | RESOURCE GROUP <group_name>
  23.     | [ DENY <deny_point> ]
  24.     | [ DENY BETWEEN <deny_point> AND <deny_point>]

Description

CREATE ROLE adds a new role to a Greenplum Database system. A role is an entity that can own database objects and have database privileges. A role can be considered a user, a group, or both depending on how it is used. You must have CREATEROLE privilege or be a database superuser to use this command.

Note that roles are defined at the system-level and are valid for all databases in your Greenplum Database system.

Parameters

name

The name of the new role.

SUPERUSER

NOSUPERUSER

If SUPERUSER is specified, the role being defined will be a superuser, who can override all access restrictions within the database. Superuser status is dangerous and should be used only when really needed. You must yourself be a superuser to create a new superuser. NOSUPERUSER is the default.

CREATEDB

NOCREATEDB

If CREATEDB is specified, the role being defined will be allowed to create new databases. NOCREATEDB (the default) will deny a role the ability to create databases.

CREATEROLE

NOCREATEROLE

If CREATEROLE is specified, the role being defined will be allowed to create new roles, alter other roles, and drop other roles. NOCREATEROLE (the default) will deny a role the ability to create roles or modify roles other than their own.

CREATEUSER

NOCREATEUSER

These clauses are obsolete, but still accepted, spellings of SUPERUSER and NOSUPERUSER. Note that they are not equivalent to the CREATEROLE and NOCREATEROLE clauses.

CREATEEXTTABLE

NOCREATEEXTTABLE

If CREATEEXTTABLE is specified, the role being defined is allowed to create external tables. The default type is readable and the default protocol is gpfdist, if not specified. Valid types are gpfdist, gpfdists, http, and https. NOCREATEEXTTABLE (the default type) denies the role the ability to create external tables. Note that external tables that use the file or execute protocols can only be created by superusers.

Use the GRANT...ON PROTOCOL command to allow users to create and use external tables with a custom protocol type, including the s3 and pxf protocols included with Greenplum Database.

INHERIT

NOINHERIT

If specified, INHERIT (the default) allows the role to use whatever database privileges have been granted to all roles it is directly or indirectly a member of. With NOINHERIT, membership in another role only grants the ability to SET ROLE to that other role.

LOGIN

NOLOGIN

If specified, LOGIN allows a role to log in to a database. A role having the LOGIN attribute can be thought of as a user. Roles with NOLOGIN are useful for managing database privileges, and can be thought of as groups. If not specified, NOLOGIN is the default, except when CREATE ROLE is invoked through its alternative spelling CREATE USER.

REPLICATION

NOREPLICATION

These clauses determine whether a role is allowed to initiate streaming replication or put the system in and out of backup mode. A role having the REPLICATION attribute is a very highly privileged role, and should only be used on roles actually used for replication. If not specified, NOREPLICATION is the default .

CONNECTION LIMIT connlimit

The number maximum of concurrent connections this role can make. The default of -1 means there is no limitation.

PASSWORD password

Sets the user password for roles with the LOGIN attribute. If you do not plan to use password authentication you can omit this option. If no password is specified, the password will be set to null and password authentication will always fail for that user. A null password can optionally be written explicitly as PASSWORD NULL.

Specifying an empty string will also set the password to null, but that was not the case before Greenplum Database version 6.21. In earlier versions, an empty string could be used, or not, depending on the authentication method and the exact version, and libpq would refuse to use it in any case. To avoid the ambiguity, specifying an empty string should be avoided.

The ENCRYPTED and UNENCRYPTED key words control whether the password is stored encrypted in the system catalogs. (If neither is specified, the default behavior is determined by the configuration parameter password_encryption.) If the presented password string is already in MD5-encrypted or SCRAM-encrypted format, then it is stored encrypted as-is, regardless of whether ENCRYPTED or UNENCRYPTED is specified (since the system cannot decrypt the specified encrypted password string). This allows reloading of encrypted passwords during dump/restore.

Note that older clients might lack support for the SCRAM authentication mechanism.

VALID UNTIL ‘timestamp’

The VALID UNTIL clause sets a date and time after which the role’s password is no longer valid. If this clause is omitted the password will never expire.

IN ROLE rolename

Adds the new role as a member of the named roles. Note that there is no option to add the new role as an administrator; use a separate GRANT command to do that.

ROLE rolename

Adds the named roles as members of this role, making this new role a group.

ADMIN rolename

The ADMIN clause is like ROLE, but the named roles are added to the new role WITH ADMIN OPTION, giving them the right to grant membership in this role to others.

RESOURCE GROUP group_name

The name of the resource group to assign to the new role. The role will be subject to the concurrent transaction, memory, and CPU limits configured for the resource group. You can assign a single resource group to one or more roles.

If you do not specify a resource group for a new role, the role is automatically assigned the default resource group for the role’s capability, admin_group for SUPERUSER roles, default_group for non-admin roles.

You can assign the admin_group resource group to any role having the SUPERUSER attribute.

You can assign the default_group resource group to any role.

You cannot assign a resource group that you create for an external component to a role.

RESOURCE QUEUE queue_name

The name of the resource queue to which the new user-level role is to be assigned. Only roles with LOGIN privilege can be assigned to a resource queue. The special keyword NONE means that the role is assigned to the default resource queue. A role can only belong to one resource queue.

Roles with the SUPERUSER attribute are exempt from resource queue limits. For a superuser role, queries always run immediately regardless of limits imposed by an assigned resource queue.

DENY deny_point

DENY BETWEEN deny_point AND deny_point

The DENY and DENY BETWEEN keywords set time-based constraints that are enforced at login. DENY sets a day or a day and time to deny access. DENY BETWEEN sets an interval during which access is denied. Both use the parameter deny_point that has the following format:

  1. DAY day [ TIME 'time' ]

The two parts of the deny_point parameter use the following formats:

For day:

  1. {'Sunday' | 'Monday' | 'Tuesday' |'Wednesday' | 'Thursday' | 'Friday' | 
  2. 'Saturday' | 0-6 }

For time:

  1. { 00-23 : 00-59 | 01-12 : 00-59 { AM | PM }}

The DENY BETWEEN clause uses two deny_point parameters:

  1. DENY BETWEEN <deny_point> AND <deny_point>

For more information and examples about time-based constraints, see “Managing Roles and Privileges” in the Greenplum Database Administrator Guide.

Notes

The preferred way to add and remove role members (manage groups) is to use GRANT and REVOKE.

The VALID UNTIL clause defines an expiration time for a password only, not for the role. The expiration time is not enforced when logging in using a non-password-based authentication method.

The INHERIT attribute governs inheritance of grantable privileges (access privileges for database objects and role memberships). It does not apply to the special role attributes set by CREATE ROLE and ALTER ROLE. For example, being a member of a role with CREATEDB privilege does not immediately grant the ability to create databases, even if INHERIT is set. These privileges/attributes are never inherited: SUPERUSER, CREATEDB, CREATEROLE, CREATEEXTTABLE, LOGIN, RESOURCE GROUP, and RESOURCE QUEUE. The attributes must be set on each user-level role.

The INHERIT attribute is the default for reasons of backwards compatibility. In prior releases of Greenplum Database, users always had access to all privileges of groups they were members of. However, NOINHERIT provides a closer match to the semantics specified in the SQL standard.

Be careful with the CREATEROLE privilege. There is no concept of inheritance for the privileges of a CREATEROLE-role. That means that even if a role does not have a certain privilege but is allowed to create other roles, it can easily create another role with different privileges than its own (except for creating roles with superuser privileges). For example, if a role has the CREATEROLE privilege but not the CREATEDB privilege, it can create a new role with the CREATEDB privilege. Therefore, regard roles that have the CREATEROLE privilege as almost-superuser-roles.

The CONNECTION LIMIT option is never enforced for superusers.

Caution must be exercised when specifying an unencrypted password with this command. The password will be transmitted to the server in clear-text, and it might also be logged in the client’s command history or the server log. The client program createuser, however, transmits the password encrypted. Also, psql contains a command \password that can be used to safely change the password later.

Examples

Create a role that can log in, but don’t give it a password:

  1. CREATE ROLE jonathan LOGIN;

Create a role that belongs to a resource queue:

  1. CREATE ROLE jonathan LOGIN RESOURCE QUEUE poweruser;

Create a role with a password that is valid until the end of 2016 (CREATE USER is the same as CREATE ROLE except that it implies LOGIN):

  1. CREATE USER joelle WITH PASSWORD 'jw8s0F4' VALID UNTIL '2017-01-01';

Create a role that can create databases and manage other roles:

  1. CREATE ROLE admin WITH CREATEDB CREATEROLE;

Create a role that does not allow login access on Sundays:

  1. CREATE ROLE user3 DENY DAY 'Sunday';

Create a role that can create readable and writable external tables of type ‘gpfdist’:

  1. CREATE ROLE jan WITH CREATEEXTTABLE(type='readable', protocol='gpfdist')
  2.    CREATEEXTTABLE(type='writable', protocol='gpfdist');

Create a role, assigning a resource group:

  1. CREATE ROLE bill RESOURCE GROUP rg_light;

Compatibility

The SQL standard defines the concepts of users and roles, but it regards them as distinct concepts and leaves all commands defining users to be specified by the database implementation. In Greenplum Database users and roles are unified into a single type of object. Roles therefore have many more optional attributes than they do in the standard.

CREATE ROLE is in the SQL standard, but the standard only requires the syntax:

  1. CREATE ROLE <name> [WITH ADMIN <rolename>]

Allowing multiple initial administrators, and all the other options of CREATE ROLE, are Greenplum Database extensions.

The behavior specified by the SQL standard is most closely approximated by giving users the NOINHERIT attribute, while roles are given the INHERIT attribute.

See Also

SET ROLE, ALTER ROLE, DROP ROLE, GRANT, REVOKE, CREATE RESOURCE QUEUE CREATE RESOURCE GROUP

Parent topic: SQL Commands