pg_policy
   The catalog pg_policy stores row level
   security policies for tables.  A policy includes the kind of
   command that it applies to (possibly all commands), the roles that it
   applies to, the expression to be added as a security-barrier
   qualification to queries that include the table, and the expression
   to be added as a WITH CHECK option for queries that attempt to
   add new records to the table.
  
Table 52.38. pg_policy Columns
| Name | Type | References | Description | 
|---|---|---|---|
| polname | name | The name of the policy | |
| polrelid | oid |  | The table to which the policy applies | 
| polcmd | char | The command type to which the policy is applied: rforSELECT,aforINSERT,wforUPDATE,dforDELETE,
       or*for all | |
| polpermissive | boolean | Is the policy permissive or restrictive? | |
| polroles | oid[] |  | The roles to which the policy is applied | 
| polqual | pg_node_tree | The expression tree to be added to the security barrier qualifications for queries that use the table | |
| polwithcheck | pg_node_tree | The expression tree to be added to the WITH CHECK qualifications for queries that attempt to add rows to the table | 
    Policies stored in pg_policy are applied only when
    pg_class.relrowsecurity is set for
    their table.