PGBOUNCER(1)                                                      PGBOUNCER(1)



NAME
       pgbouncer - Lightweight connection pooler for PostgreSQL.

SYNOPSIS
       pgbouncer [-d][-R][-v][-u user] <pgbouncer.ini>
       pgbouncer -V|-h

       On Windows computers, the options are:

       pgbouncer.exe [-v][-u user] <pgbouncer.ini>
       pgbouncer.exe -V|-h

       Additional options for setting up a Windows service:

       pgbouncer.exe -regservice   <pgbouncer.ini>
       pgbouncer.exe -unregservice <pgbouncer.ini>

DESCRIPTION
       pgbouncer is a PostgreSQL connection pooler. Any target application can
       be connected to pgbouncer as if it were a PostgreSQL server, and
       pgbouncer will create a connection to the actual server, or it will
       reuse one of its existing connections.

       The aim of pgbouncer is to lower the performance impact of opening new
       connections to PostgreSQL.

       In order not to compromise transaction semantics for connection
       pooling, pgbouncer supports several types of pooling when rotating
       connections:

       Session pooling
           Most polite method. When client connects, a server connection will
           be assigned to it for the whole duration the client stays
           connected. When the client disconnects, the server connection will
           be put back into the pool. This is the default method.

       Transaction pooling
           A server connection is assigned to client only during a
           transaction. When PgBouncer notices that transaction is over, the
           server connection will be put back into the pool.

       Statement pooling
           Most aggressive method. The server connection will be put back into
           pool immediately after a query completes. Multi-statement
           transactions are disallowed in this mode as they would break.

       The administration interface of pgbouncer consists of some new SHOW
       commands available when connected to a special virtual database
       pgbouncer.

QUICK-START
       Basic setup and usage as following.

        1. Create a pgbouncer.ini file. Details in pgbouncer(5). Simple
           example:

               [databases]
               template1 = host=127.0.0.1 port=5432 dbname=template1

               [pgbouncer]
               listen_port = 6543
               listen_addr = 127.0.0.1
               auth_type = md5
               auth_file = users.txt
               logfile = pgbouncer.log
               pidfile = pgbouncer.pid
               admin_users = someuser

        2. Create a users.txt file:

               "someuser" "same_password_as_in_server"

        3. Launch pgbouncer:

               $ pgbouncer -d pgbouncer.ini

        4. Have your application (or the psql client) connect to pgbouncer
           instead of directly to PostgreSQL server.

               $ psql -p 6543 -U someuser template1

        5. Manage pgbouncer by connecting to the special administration
           database pgbouncer and issuing show help; to begin:

               $ psql -p 6543 -U someuser pgbouncer
               pgbouncer=# show help;
               NOTICE:  Console usage
               DETAIL:
                 SHOW [HELP|CONFIG|DATABASES|FDS|POOLS|CLIENTS|SERVERS|SOCKETS|LISTS|VERSION]
                 SET key = arg
                 RELOAD
                 PAUSE
                 SUSPEND
                 RESUME
                 SHUTDOWN

        6. If you made changes to the pgbouncer.ini file, you can reload it
           with:

               pgbouncer=# RELOAD;

COMMAND LINE SWITCHES
       -d
           Run in background. Without it the process will run in foreground.
           Note: Does not work on Windows, pgbouncer need to run as service
           there.

       -R
           Do an online restart. That means connecting to the running process,
           loading the open sockets from it, and then using them. If there is
           no active process, boot normally. Note: Works only if OS supports
           Unix sockets and the unix_socket_dir is not disabled in config.
           Does not work on Windows machines.

       -u user
           Switch to the given user on startup.

       -v
           Increase verbosity. Can be used multiple times.

       -q
           Be quiet - do not log to stdout. Note this does not affect logging
           verbosity, only that stdout is not to be used. For use in init.d
           scripts.

       -V
           Show version.

       -h
           Show short help.

       -regservice
           Win32: Register pgbouncer to run as Windows service. The
           service_name config parameter value is used as name to register
           under.

       -unregservice
           Win32: Unregister Windows service.

ADMIN CONSOLE
       The console is available by connecting as normal to the database
       pgbouncer

           $ psql -p 6543 pgbouncer

       Only users listed in configuration parameters admin_users or
       stats_users are allowed to login to the console. (Except when
       auth_mode=any, then any user is allowed in as an admin.)

       Additionally, the username pgbouncer is allowed to log in without
       password, if the login comes via Unix socket and the client has same
       Unix user uid as the running process.

   SHOW COMMANDS
       The SHOW commands output information. Each command is described below.

       SHOW STATS;
           Shows statistics.

           database
               Statistics are presented per database.

           total_requests
               Total number of SQL requests pooled by pgbouncer.

           total_received
               Total volume in bytes of network traffic received by pgbouncer.

           total_sent
               Total volume in bytes of network traffic sent by pgbouncer.

           total_query_time
               Total number of microseconds spent by pgbouncer when actively
               connected to PostgreSQL.

           avg_req
               Average requests per second in last stat period.

           avg_recv
               Average received (from clients) bytes per second.

           avg_sent
               Average sent (to clients) bytes per second.

           avg_query
               Average query duration in microseconds.

       SHOW SERVERS;
           type
               S, for server.

           user
               Username pgbouncer uses to connect to server.

           database
               Database name.

           state
               State of the pgbouncer server connection, one of active, used
               or idle.

           addr
               IP address of PostgreSQL server.

           port
               Port of PostgreSQL server.

           local_addr
               Connection start address on local machine.

           local_port
               Connection start port on local machine.

           connect_time
               When the connection was made.

           request_time
               When last request was issued.

           ptr
               Address of internal object for this connection. Used as unique
               ID.

           link
               Address of client connection the server is paired with.

       SHOW CLIENTS;
           type
               C, for client.

           user
               Client connected user.

           database
               Database name.

           state
               State of the client connection, one of active, used, waiting or
               idle.

           addr
               IP address of client.

           port
               Port client is connected to.

           local_addr
               Connection end address on local machine.

           local_port
               Connection end port on local machine.

           connect_time
               Timestamp of connect time.

           request_time
               Timestamp of latest client request.

           ptr
               Address of internal object for this connection. Used as unique
               ID.

           link
               Address of server connection the client is paired with.

       SHOW POOLS;
           A new pool entry is made for each couple of (database, user).

           database
               Database name.

           user
               Username.

           cl_active
               Count of currently active client connections.

           cl_waiting
               Count of currently waiting client connections.

           sv_active
               Count of currently active server connections.

           sv_idle
               Count of currently idle server connections.

           sv_used
               Count of currently used server connections.

           sv_tested
               Count of currently tested server connections.

           sv_login
               Count of server connections currently logged in to PostgreSQL.

           maxwait
               How long the first (oldest) client in queue has waited, in
               seconds. If this starts increasing, then the current pool of
               servers does not handle requests quick enough. Reason may be
               either overloaded server or just too small of a pool_size
               setting.

       SHOW LISTS;
           Show following internal information, in columns (not rows):

           databases
               Count of databases.

           users
               Count of users.

           pools
               Count of pools.

           free_clients
               Count of free clients.

           used_clients
               Count of used clients.

           login_clients
               Count of clients in login state.

           free_servers
               Count of free servers.

           used_servers
               Count of used servers.

       SHOW USERS;
           Shows one line per user, under the name column name.

       SHOW DATABASES;
           name
               Name of configured database entry.

           host
               Host pgbouncer connects to.

           port
               Port pgbouncer connects to.

           database
               Actual database name pgbouncer connects to.

           force_user
               When user is part of the connection string, the connection
               between pgbouncer and PostgreSQL is forced to the given user,
               whatever the client user.

           pool_size
               Maximum number of server connections.

       SHOW FDS;
           Shows list of fds in use. When the connected user has username
           "pgbouncer", connects through Unix socket and has same UID as
           running process, the actual fds are passed over the connection.
           This mechanism is used to do an online restart. Note: This does not
           work on Windows machines.

           fd
               File descriptor numeric value.

           task
               One of pooler, client or server.

           user
               User of the connection using the FD.

           database
               Database of the connection using the FD.

           addr
               IP address of the connection using the FD, unix if a unix
               socket is used.

           port
               Port used by the connection using the FD.

           cancel
               Cancel key for this connection.

           link
               fd for corresponding server/client. NULL if idle.

       SHOW CONFIG;
           Show the current configuration settings, one per row, with
           following columns:

           key
               Configuration variable name

           value
               Configuration value

           changeable
               Either yes or no, shows if the variable can be changed while
               running. If no, the variable can be changed only boot-time.

       SHOW DNS_HOSTS
           Show hostnames in DNS cache.

           hostname
               Host name.

           ttl
               How meny seconds until next lookup.

           addrs
               Comma separated list of addresses.

       SHOW DNS_ZONES
           Show DNS zones in cache.

           zonename
               Zone name.

           serial
               Current serial.

           count
               Hostnames belonging to this zone.

   PROCESS CONTROLLING COMMANDS
       PAUSE [db];
           PgBouncer tries to disconnect from all servers, first waiting for
           all queries to complete. The command will not return before all
           queries are finished. To be used at the time of database restart.

           If database name is given, only that database will be paused.

       KILL db;
           Immediately drop all client and server connections on given
           database.

       SUSPEND;
           All socket buffers are flushed and PgBouncer stops listening for
           data on them. The command will not return before all buffers are
           empty. To be used at the time of PgBouncer online reboot.

       RESUME [db];
           Resume work from previous PAUSE or SUSPEND command.

       SHUTDOWN;
           The PgBouncer process will exit.

       RELOAD;
           The PgBouncer process will reload its configuration file and update
           changeable settings.

   SIGNALS
       SIGHUP
           Reload config. Same as issuing command RELOAD; on console.

       SIGINT
           Safe shutdown. Same as issuing PAUSE; and SHUTDOWN; on console.

       SIGTERM
           Immediate shutdown. Same as issuing SHUTDOWN; on console.

   LIBEVENT SETTINGS
       From libevent docs:

           It is possible to disable support for epoll, kqueue, devpoll, poll
           or select by setting the environment variable EVENT_NOEPOLL,
           EVENT_NOKQUEUE, EVENT_NODEVPOLL, EVENT_NOPOLL or EVENT_NOSELECT,
           respectively.

           By setting the environment variable EVENT_SHOW_METHOD, libevent
           displays the kernel notification method that it uses.

SEE ALSO
       pgbouncer(5) - manpage of configuration settings descriptions.

       http://wiki.postgresql.org/wiki/PgBouncer



                                  01/19/2012                      PGBOUNCER(1)
