PGBOUNCER(5)                                                      PGBOUNCER(5)



NAME
       pgbouncer - Lightweight connection pooler for PostgreSQL.

SYNOPSIS
       [databases]
       db = ...

       [pgbouncer]
       ...

DESCRIPTION
       Config file is in "ini" format. Section names are between " and ".
       Lines starting with ";" or "" are taken as comments and ignored. The
       characters ";" and "" are not recognized when they appear later in the
       line.

SECTION [PGBOUNCER]
   Generic settings
       logfile
           Specifies log file. Log file is kept open so after rotation kill
           -HUP or on console RELOAD; should be done. Note: On Windows
           machines, the service must be stopped and started.

           Default: not set.

       pidfile
           Specifies the pid file. Without a pidfile, daemonization is not
           allowed.

           Default: not set.

       listen_addr
           Specifies list of addresses, where to listen for TCP connections.
           You may also use * meaning "listen on all addresses". When not set,
           only Unix socket connections are allowed.

           Addresses can be specified numerically (IPv4/IPv6) or by name.

           Default: not set

       listen_port
           Which port to listen on. Applies to both TCP and Unix sockets.

           Default: 6432

       unix_socket_dir
           Specifies location for Unix sockets. Applies to both listening
           socket and server connections. If set to an empty string, Unix
           sockets are disabled. Required for online reboot (-R) to work.
           Note: Not supported on Windows machines.

           Default: /tmp

       unix_socket_mode
           Filesystem mode for unix socket.

           Default: 0777

       unix_socket_group
           Group name to use for unix socket.

           Default: not set

       user
           If set, specifies the Unix user to change to after startup. Works
           only if PgBouncer is started as root or if user is the same as the
           current user. Note: Not supported on Windows machines.

           Default: not set

       auth_file
           The name of the file to load user names and passwords from. The
           file format is the same as the PostgreSQL pg_auth/pg_pwd file, so
           this setting can be pointed directly to one of those backend files.

           Default: not set.

       auth_type
           How to authenticate users.

           md5
               Use MD5-based password check.  auth_file may contain both
               MD5-encrypted or plain-text passwords. This is the default
               authentication method.

           crypt
               Use crypt(3) based password check.  auth_file must contain
               plain-text passwords.

           plain
               Clear-text password is sent over wire.

           trust
               No authentication is done. Username must still exist in
               auth_file.

           any
               Like the trust method, but the username given is ignored.
               Requires that all databases are configured to log in as
               specific user. Additionally, the console database allows any
               user to log in as admin.

       pool_mode
           Specifies when a server connection can be reused by other clients.

           session
               Server is released back to pool after client disconnects.
               Default.

           transaction
               Server is released back to pool after transaction finishes.

           statement
               Server is released back to pool after query finishes. Long
               transactions spanning multiple statements are disallowed in
               this mode.

       max_client_conn
           Maximum number of client connections allowed. When increased then
           the file descriptor limits should also be increased. Note that
           actual number of file descriptors used is more than
           max_client_conn. Theoretical maximum used is:

               max_client_conn + (max_pool_size * total_databases * total_users)

           if each user connects under its own username to server. If a
           database user is specified in connect string (all users connect
           under same username), the theoretical maximum is:

               max_client_conn + (max_pool_size * total_databases)

           The theoretical maximum should be never reached, unless somebody
           deliberately crafts special load for it. Still, it means you should
           set the number of file descriptors to a safely high number.

           Search for ulimit in your favourite shell man page. Note: ulimit
           does not apply in a Windows environment.

           Default: 100

       default_pool_size
           How many server connections to allow per user/database pair. Can be
           overridden in the per-database configuration.

           Default: 20

       min_pool_size
           Add more server connections to pool if below this number. Improves
           behaviour when usual load comes suddenly back after period of total
           inactivity.

           Default: 0 (disabled)

       reserve_pool_size
           How many additional connections to allow to a pool. 0 disables.

           Default: 0 (disabled)

       reserve_pool_timeout
           If a client has not been serviced in this many seconds, pgbouncer
           enables use of additional connections from reserve pool. 0
           disables.

           Default: 5

       server_round_robin
           By default, pgbouncer reuses server connections in LIFO (last-in,
           first-out) manner, so that few connections get the most load. This
           gives best performance if you have a single server serving a
           database. But if there is TCP round-robin behind a database IP,
           then it is better if pgbouncer also uses connections in that
           manner, thus achieving uniform load.

           Default: 0

       ignore_startup_parameters
           By default, PgBouncer allows only parameters it can keep track of
           in startup packets - client_encoding, datestyle, timezone and
           standard_conforming_strings.

           All others parameters will raise an error. To allow others
           parameters, they can be specified here, so that pgbouncer knows
           that they are handled by admin and it can ignore them.

           Default: empty

       disable_pqexec
           Disable Simple Query protocol (PQexec). Unlike Extended Query
           protocol, Simple Query allows multiple queries in one packet, which
           allows some classes of SQL-injection attacks. Disabling it can
           improve security. Obviously this means only clients that
           exclusively use Extended Query protocol will stay working.

           Default: 0

   Log settings
       syslog
           Toggles syslog on/off As for windows environment, eventlog is used
           instead.

           Default: 0

       syslog_ident
           Under what name to send logs to syslog.

           Default: pgbouncer (program name)

       syslog_facility
           Under what facility to send logs to syslog. Possibilities: auth,
           authpriv, daemon, user, local0-7

           Default: daemon

       log_connections
           Log successful logins.

           Default: 1

       log_disconnections
           Log disconnections with reasons.

           Default: 1

       log_pooler_errors
           Log error messages pooler sends to clients.

           Default: 1

       stats_period
           Period for writing aggregated stats into log.

           Default: 60

   Console access control
       admin_users
           Comma-separated list of database users that are allowed to connect
           and run all commands on console. Ignored when auth_mode=any, in
           which case any username is allowed in as admin.

           Default: empty

       stats_users
           Comma-separated list of database users that are allowed to connect
           and run read-only queries on console. Thats means all SHOW commands
           except SHOW FDS.

           Default: empty.

   Connection sanity checks, timeouts
       server_reset_query
           Query sent to server on connection release, before making it
           available to other clients. At that moment no transaction is in
           progress so it should not include ABORT or ROLLBACK.

           A good choice for Postgres 8.2 and below is:

               server_reset_query = RESET ALL; SET SESSION AUTHORIZATION DEFAULT;

           for 8.3 and above its enough to do:

               server_reset_query = DISCARD ALL;

           When transaction pooling is used, the server_reset_query should be
           empty, as clients should not use any session features.

           Default: DISCARD ALL

       server_check_delay
           How long to keep released connections available for immediate
           re-use, without running sanity-check queries on it. If 0 then the
           query is ran always.

           Default: 30

       server_check_query
           Simple do-nothing query to check if the server connection is alive.

           If an empty string, then sanity checking is disabled.

           Default: SELECT 1;

       server_lifetime
           The pooler will try to close server connections that have been
           connected longer than this. Setting it to 0 means the connection is
           to be used only once, then closed. [seconds]

           Default: 3600

       server_idle_timeout
           If a server connection has been idle more than this many seconds,
           and there are too many connections in the pool, this one can be
           dropped. If 0 then timeout is disabled. [seconds]

           Default: 600

       server_connect_timeout
           If connection and login won't finish in this amount of time, the
           connection will be closed. [seconds]

           Default: 15

       server_login_retry
           If login failed, because of failure from connect() or
           authentication that pooler waits this much before retrying to
           connect. [seconds]

           Default: 15

       client_login_timeout
           If a client connects but does not manage to login in this amount of
           time, it will be disconnected. Mainly needed to avoid dead
           connections stalling SUSPEND and thus online restart. [seconds]

           Default: 60

       autodb_idle_timeout
           If the automatically created (via "*") database pools have been
           unused this many seconds, they are freed. The negative aspect of
           that is that their statistics are also forgotten. [seconds]

           Default: 3600

       dns_max_ttl
           How long the DNS lookups can be cached. If a DNS lookup returns
           several answers, pgbouncer will robin-between them in the meantime.
           Actual DNS TTL is ignored. [seconds]

           Default: 15

       dns_zone_check_period
           Period to check if zone serial has changed.

           PgBouncer can collect dns zones from hostnames (everything after
           first dot) and then periodically check if zone serial changes. If
           it notices changes, all hostnames under that zone are looked up
           again. If any host ip changes, it's connections are invalidated.

           Works only with UDNS backend (--with-udns to configure).

           Default: 0 (disabled)

   Dangerous timeouts
       Setting following timeouts cause unexpected errors.

       query_timeout
           Queries running longer than that are canceled. This should be used
           only with slightly smaller server-side statement_timeout, to apply
           only for network problems. [seconds]

           Default: 0 (disabled)

       query_wait_timeout
           Maximum time queries are allowed to spend waiting for execution. If
           the query is not assigned to a server during that time, the client
           is disconnected. This is used to prevent unresponsive servers from
           grabbing up connections. [seconds]

           Default: 0 (disabled)

       client_idle_timeout
           Client connections idling longer than this many seconds are closed.
           This should be larger than the client-side connection lifetime
           settings, and only used for network problems. [seconds]

           Default: 0 (disabled)

       idle_transaction_timeout
           If client has been in "idle in transaction" state longer, it will
           be disconnected. [seconds]

           Default: 0 (disabled)

   Low-level network settings
       pkt_buf
           Internal buffer size for packets. Affects size of TCP packets sent
           and general memory usage. Actual libpq packets can be larger than
           this so, no need to set it large.

           Default: 2048

       listen_backlog
           Backlog argument for listen(2). Determines how many new unanswered
           connection attempts are kept in queue. When queue is full, further
           new connections are dropped.

           Default: 128

       sbuf_loopcnt
           How many times to process data on one connection, before
           proceeding. Without this limit, one connection with a big resultset
           can stall PgBouncer for a long time. One loop processes one pkt_buf
           amount of data. 0 means no limit.

           Default: 5

       tcp_defer_accept
           For details on this and other tcp options, please see man 7 tcp.

           Default: 45 on Linux, otherwise 0

       tcp_socket_buffer
           Default: not set

       tcp_keepalive
           Turns on basic keepalive with OS defaults.

           On Linux, the system defaults are tcp_keepidle=7200,
           tcp_keepintvl=75, tcp_keepcnt=9. They are probably similar on other
           OS-es.

           Default: 1

       tcp_keepcnt
           Default: not set

       tcp_keepidle
           Default: not set

       tcp_keepintvl
           Default: not set

SECTION [DATABASES]
       This contains key=value pairs where key will be taken as a database
       name and value as a libpq connect-string style list of key=value pairs.
       As actual libpq is not used, so not all features from libpq can be used
       (service=, .pgpass).

       Database name can contain characters [0-9A-Za-z_.-] without quoting.
       Names that contain other chars need to be quoted with standard SQL
       ident quoting: double quotes where "" is taken as single quote.

       "\*" acts as fallback database: if the exact name does not exist, its
       value is taken as connect string for requested database. Such
       automatically created database entries are cleaned up if they stay idle
       longer then the time specified in autodb_idle_timeout parameter.

   Location parameters
       dbname
           Destination database name.

           Default: same as client-side database name.

       host
           Hostname or IP address to connect to. Hostnames are resolved on
           connect time, the result is cached per dns_max_ttl parameter. If
           DNS returns several results, they are used in round-robin manner.

           Default: not set, meaning to use a Unix socket.

       port
           Default: 5432

       user, password
           If user= is set, all connections to the destination database will
           be done with the specified user, meaning that there will be only
           one pool for this database.

           Otherwise PgBouncer tries to log into the destination database with
           client username, meaning that there will be one pool per user.

   Pool configuration
       pool_size
           Set maximum size of pools for this database. If not set, the
           default_pool_size is used.

       connect_query
           Query to be executed after a connection is established, but before
           allowing the connection to be used by any clients. If the query
           raises errors, they are logged but ignored otherwise.

   Extra parameters
       They allow setting default parameters on server connection.

       Note that since version 1.1 PgBouncer tracks client changes for their
       values, so their use in pgbouncer.ini is deprecated now.

       client_encoding
           Ask specific client_encoding from server.

       datestyle
           Ask specific datestyle from server.

       timezone
           Ask specific timezone from server.

AUTHENTICATION FILE FORMAT
       PgBouncer needs its own user database. The users are loaded from a text
       file in following format:

           "username1" "password" ...
           "username2" "md5abcdef012342345" ...

       There should be at least 2 fields, surrounded by double quotes. The
       first field is the username and the second is either a plain-text or a
       MD5-hidden password. PgBouncer ignores the rest of the line.

       This file format is equivalent to text files used by PostgreSQL 8.x for
       authentication info, thus allowing PgBouncer to work directly on
       PostgreSQL authentication files in data directory.

       Since PostgreSQL 9.0, the text files are not used anymore. Thus the
       auth file needs to be generated. See ./etc/mkauth.py for sample script
       to generate auth file from pg_shadow table.

       PostgreSQL MD5-hidden password format:

           "md5" + md5(password + username)

       So user admin with password 1234 will have MD5-hidden password
       md545f2603610af569b6155c45067268c6b.

EXAMPLE
   Minimal config
           [databases]
           template1 = host=127.0.0.1 dbname=template1

           [pgbouncer]
           pool_mode = session
           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
           stats_users = stat_collector

   Database defaults
           [databases]

           ; foodb over unix socket
           foodb =

           ; redirect bardb to bazdb on localhost
           bardb = host=127.0.0.1 dbname=bazdb

           ; access to destination database will go with single user
           forcedb = host=127.0.0.1 port=300 user=baz password=foo client_encoding=UNICODE datestyle=ISO

SEE ALSO
       pgbouncer(1) - manpage for general usage, console commands.

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



                                  05/28/2012                      PGBOUNCER(5)
