is_superuser
transaction_read_only
transaction_deferrable
integer_datetimes
data_checksums
max_function_args
max_index_keys
max_identifier_length
block_size
segment_size
wal_block_size
wal_segment_size
server_version_num
seed
lc_collate
lc_ctype
server_encoding
server_version
role
session_authorization
transaction_isolation
config_file
gp_is_writer
gp_write_shared_snapshot
dev_opt_unsafe_truncate_in_subtransaction
gp_dbid
gp_contentid
gp_command_count
gp_qd_port
gp_session_id
gp_server_version_num
gp_session_role
gp_role
gp_qd_hostname
gp_server_version
