_pg_char_max_length
_pg_char_octet_length
_pg_datetime_precision
_pg_expandarray
_pg_index_position
_pg_interval_type
_pg_keysequal
_pg_numeric_precision
_pg_numeric_precision_radix
_pg_numeric_scale
_pg_truetypid
_pg_truetypmod
current_database
current_query
current_schema
current_schemas
current_setting
current_user
currtid
getpgusername
host
hostmask
session_user
inet_client_addr