pg_authid

The pg_authid table contains information about database authorization identifiers (roles). A role subsumes the concepts of users and groups. A user is a role with the rolcanlogin flag set. Any role (with or without rolcanlogin) may have other roles as members. See pg_auth_members.

Since this catalog contains passwords, it must not be publicly readable. pg_roles is a publicly readable view on pg_authid that blanks out the password field.

Because user identities are system-wide, pg_authid is shared across all databases in a Greenplum Database system: there is only one copy of pg_authid per system, not one per database.

column	type	description
`oid`	oid	Row identifier (hidden attribute; must be explicitly selected)
`rolname`	name	Role name
`rolsuper`	boolean	Role has superuser privileges
`rolinherit`	boolean	Role automatically inherits privileges of roles it is a member of
`rolcreaterole`	boolean	Role may create more roles
`rolcreatedb`	boolean	Role may create databases
`rolcatupdate`	boolean	Role may update system catalogs directly. (Even a superuser may not do this unless this column is true)
`rolcanlogin`	boolean	Role may log in. That is, this role can be given as the initial session authorization identifier
`rolreplication`	boolean	Role is a replication role. That is, this role can initiate streaming replication and set/unset the system backup mode using `pg_start_backup` and `pg_stop_backup`.
`rolconnlimit`	int4	For roles that can log in, this sets maximum number of concurrent connections this role can make. `-1` means no limit
`rolpassword`	text	Password (possibly encrypted); NULL if none. The format depends on the form of encryption used.¹
`rolvaliduntil`	timestamptz	Password expiry time (only used for password authentication); NULL if no expiration
`rolresqueue`	oid	Object ID of the associated resource queue ID in pg_resqueue
`rolcreaterextgpfd`	boolean	Privilege to create read external tables with the `gpfdist` or `gpfdists` protocol
`rolcreaterexhttp`	boolean	Privilege to create read external tables with the `http` protocol
`rolcreatewextgpfd`	boolean	Privilege to create write external tables with the `gpfdist` or `gpfdists` protocol
`rolresgroup`	oid	Object ID of the associated resource group ID in pg_resgroup

Notes¹:

For an MD5-encrypted password, rolpassword column will begin with the string md5 followed by a 32-character hexadecimal MD5 hash. The MD5 hash will be of the user's password concatenated to their user name. For example, if user joe has password xyzzy Greenplum Database will store the md5 hash of xyzzyjoe.
If the password is encrypted with SCRAM-SHA-256, the rolpassword column has the format:
```
SCRAM-SHA-256$<iteration count>:<salt>$<StoredKey>:<ServerKey>
```
where <salt>, <StoredKey> and <ServerKey> are in Base64-encoded format. This format is the same as that specified by RFC 5803.
If the password is encrypted with SHA-256, the rolpassword column is a 64-byte hexadecimal string prefixed with the characters sha256.

A password that does not follow any of these formats is assumed to be unencrypted.

Parent topic: System Catalogs Definitions