pg_db_role_setting records the default values that have been set for run-time configuration variables, for each role and database combination.
Unlike most system catalogs,
pg_db_role_setting is shared across all databases of a cluster: there is only one copy of
pg_db_role_setting per cluster, not one per database.
|The OID of the database the setting is applicable to, or zero if not database-specific|
|The OID of the role the setting is applicable to, or zero if not role-specific|
|Defaults for run-time configuration variables|