54.65. pg_user_mapping
 The catalog pg_user_mapping stores the mappings from local user to remote. Access to this catalog is restricted from normal users, use the view pg_user_mappings instead. 
Table 54.66. pg_user_mapping Columns
Column Type Description  | 
|---|
 Row identifier  | 
 OID of the local role being mapped, 0 if the user mapping is public  | 
 The OID of the foreign server that contains this mapping  | 
 User mapping specific options, as “keyword=value” strings  |