51.94. pg_user_mappings
 The view pg_user_mappings provides access to information about user mappings. This is essentially a publicly readable view of pg_user_mapping that leaves out the options field if the user has no rights to use it. 
Table 51.95. pg_user_mappings Columns
Column Type Description  | 
|---|
 OID of the user mapping  | 
 The OID of the foreign server that contains this mapping  | 
 Name of the foreign server  | 
 OID of the local role being mapped, 0 if the user mapping is public  | 
 Name of the local user to be mapped  | 
 User mapping specific options, as “keyword=value” strings  | 
 To protect password information stored as a user mapping option, the umoptions column will read as null unless one of the following applies: 
current user is the user being mapped, and owns the server or holds
USAGEprivilege on itcurrent user is the server owner and mapping is for
PUBLICcurrent user is a superuser