mydb=# SELECT name, current_setting(name)        
  FROM pg_settings
  WHERE source NOT IN ('default', 'override');
             name             |         current_setting          
------------------------------+----------------------------------
 application_name             | psql
 autovacuum                   | off
 checkpoint_completion_target | 0.9
 checkpoint_segments          | 32
 client_encoding              | UTF8
 DateStyle                    | ISO, MDY
 default_text_search_config   | pg_catalog.english
 effective_cache_size         | 3300MB
 effective_io_concurrency     | 8
 external_pid_file            | /var/run/postgresql/9.1-main.pid
 fsync                        | off
 full_page_writes             | off
 hot_standby                  | on
 hot_standby_feedback         | on
 lc_messages                  | en_US.UTF-8
 lc_monetary                  | en_US.UTF-8
 lc_numeric                   | en_US.UTF-8
 lc_time                      | en_US.UTF-8
 listen_addresses             | *
 log_directory                | /var/log/postgresql
 log_file_mode                | 0640
 log_line_prefix              | %t %p 
 log_min_duration_statement   | 10s
 log_rotation_size            | 100MB
 log_timezone                 | UTC
 logging_collector            | on
 maintenance_work_mem         | 512MB
 max_connections              | 200
 max_stack_depth              | 2MB
 max_standby_archive_delay    | 2h
 max_standby_streaming_delay  | 2h
 max_wal_senders              | 0
 port                         | 5432
 shared_buffers               | 512MB
 ssl                          | on
 ssl_renegotiation_limit      | 0
 synchronous_commit           | off
 TimeZone                     | UTC
 unix_socket_directory        | /var/run/postgresql
 wal_keep_segments            | 1700
 wal_level                    | minimal
(41 rows)