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Manual Reference Pages  -  PGBOUNCER (5)


pgbouncer.ini - configuration file for pgbouncer \$1 \n[an-margin] level \n[rst2man-indent-level] level margin: \n[rst2man-indent\n[rst2man-indent-level]] - \n[rst2man-indent0] \n[rst2man-indent1] \n[rst2man-indent2]


Generic Settings
Log Settings
Console Access Control
Connection Sanity Checks, Timeouts
Tls Settings
Dangerous Timeouts
Low-level Network Settings
Section [databases]
Section [users]
Include Directive
Authentication File Format
Hba File Format
See Also


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.



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.


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

Default: not set.


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


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

Default: 6432


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


Filesystem mode for unix socket.

Default: 0777


Group name to use for unix socket.

Default: not set


If set, specifies the Unix user to change to after startup. Works only if PgBouncer is started as root or if it\(aqs already running as given user.

Note: Not supported on Windows machines.

Default: not set


The name of the file to load user names and passwords from. The file format is the same as the PostgreSQL 8.x pg_auth/pg_pwd file, so this setting can be pointed directly to one of those backend files. Since version 9.0, PostgreSQL does not use such text file, so it must be generated manually. See section  Authentication file format below about details.

Default: not set.


HBA configuration file to use when  auth_type is hba. Supported from version 1.7 onwards.

Default: not set


How to authenticate users.
hba Actual auth type is loaded from  auth_hba_file. This allows different authentication methods different access paths. Example: connection over unix socket use peer auth method, connection over TCP must use TLS. Supported from version 1.7 onwards.
cert Client must connect over TLS connection with valid client cert. Username is then taken from CommonName field from certificate.
md5 Use MD5-based password check.  auth_file may contain both MD5-encrypted or plain-text passwords. This is the default authentication method.
plain Clear-text password is sent over wire. Deprecated.
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.


Query to load user\(aqs password from database.

Direct access to pg_shadow requires admin rights. It\(aqs preferable to use non-admin user that calls SECURITY DEFINER function instead.

Default: SELECT usename, passwd FROM pg_shadow WHERE usename=$1


Specifies when a server connection can be reused by other clients.
  Server is released back to pool after client disconnects. Default.
  Server is released back to pool after transaction finishes.
  Server is released back to pool after query finishes. Long transactions spanning multiple statements are disallowed in this mode.


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


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

Default: 20


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)


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

Default: 0 (disabled)


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

Default: 5.0


Do not allow more than this many connections per-database (regardless of pool - i.e. user). It should be noted that when you hit the limit, closing a client connection to one pool will not immediately allow a server connection to be established for another pool, because the server connection for the first pool is still open. Once the server connection closes (due to idle timeout), a new server connection will immediately be opened for the waiting pool.

Default: unlimited


Do not allow more than this many connections per-user (regardless of pool - i.e. user). It should be noted that when you hit the limit, closing a client connection to one pool will not immediately allow a server connection to be established for another pool, because the server connection for the first pool is still open. Once the server connection closes (due to idle timeout), a new server connection will immediately be opened for the waiting pool.


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


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 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


Add the client host address and port to the application name setting set on connection start. This helps in identifying the source of bad queries etc. This logic applies only on start of connection, if application_name is later changed with SET, pgbouncer does not change it again.

Default: 0


Show location of current config file. Changing it will make PgBouncer use another config file for next RELOAD / SIGHUP.

Default: file from command line.


Used on win32 service registration.

Default: pgbouncer


Alias for  service_name.



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

Default: 0


Under what name to send logs to syslog.

Default: pgbouncer (program name)


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

Default: daemon


Log successful logins.

Default: 1


Log disconnections with reasons.

Default: 1


Log error messages pooler sends to clients.

Default: 1


Period for writing aggregated stats into log.

Default: 60


Increase verbosity. Mirrors "-v" switch on command line. Using "-v -v" on command line is same as verbose=2 in config.

Default: 0



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

Default: empty


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.



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.

The query is supposed to clean any changes made to database session so that next client gets connection in well-defined state. Default is DISCARD ALL which cleans everything, but that leaves next client no pre-cached state. It can be made lighter, eg DEALLOCATE ALL to just drop prepared statements, if application does not break when some state is kept around.

When transaction pooling is used, the  server_reset_query is not used, as clients must not use any session-based features as each transaction ends up in different connection and thus gets different session state.



Whether  server_reset_query should be run in all pooling modes. When this setting is off (default), the  server_reset_query will be run only in pools that are in sessions-pooling mode. Connections in transaction-pooling mode should not have any need for reset query.

It is workaround for broken setups that run apps that use session features over transaction-pooled pgbouncer. Is changes non-deterministic breakage to deterministic breakage - client always lose their state after each transaction.

Default: 0


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: 30.0


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

If an empty string, then sanity checking is disabled.

Default: SELECT 1;


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: 3600.0


If a server connection has been idle more than this many seconds it will be dropped. If 0 then timeout is disabled. [seconds]

Default: 600.0


If connection and login won\(aqt finish in this amount of time, the connection will be closed. [seconds]

Default: 15.0


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

Default: 15.0


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: 60.0


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: 3600.0


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: 15.0


How long error and NXDOMAIN DNS lookups can be cached. [seconds]

Default: 15.0


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\(aqs connections are invalidated.

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

Default: 0.0 (disabled)



TLS mode to use for connections from clients. TLS connections are disabled by default. When enabled,  client_tls_key_file and  client_tls_cert_file must be also configured to set up key and cert PgBouncer uses to accept client connections.
  Plain TCP. If client requests TLS, it\(aqs ignored. Default.
allow If client requests TLS, it is used. If not, plain TCP is used. If client uses client-certificate, it is not validated.
prefer Same as allow.
  Client must use TLS. If not, client connection is rejected. If client uses client-certificate, it is not validated.
  Client must use TLS with valid client certificate.
  Same as verify-ca.


Private key for PgBouncer to accept client connections.

Default: not set.


Certificate for private key. Clients can validate it.

Default: not set.


Root certificate file to validate client certificates.

Default: unset.


Which TLS protocol versions are allowed. Allowed values: tlsv1.0, tlsv1.1, tlsv1.2. Shortcuts: all (tlsv1.0,tlsv1.1,tlsv1.2), secure (tlsv1.2), legacy (all).

Default: all


Default: fast


Elliptic Curve name to use for ECDH key exchanges.

Allowed values: none (DH is disabled), auto (256-bit ECDH), curve name.

Default: auto


DHE key exchange type.

Allowed values: none (DH is disabled), auto (2048-bit DH), legacy (1024-bit DH).

Default: auto


TLS mode to use for connections to PostgreSQL servers. TLS connections are disabled by default.
  Plain TCP. TCP is not event requested from server. Default.
allow FIXME: if server rejects plain, try TLS?
prefer TLS connection is always requested first from PostgreSQL, when refused connection will be establised over plain TCP. Server certificate is not validated.
  Connection must go over TLS. If server rejects it, plain TCP is not attempted. Server certificate is not validated.
  Connection must go over TLS and server certificate must be valid according to  server_tls_ca_file. Server hostname is not checked against certificate.
  Connection must go over TLS and server certificate must be valid according to  server_tls_ca_file. Server hostname must match certificate info.


Root certificate file to validate PostgreSQL server certificates.

Default: unset.


Private key for PgBouncer to authenticate against PostgreSQL server.

Default: not set.


Certificate for private key. PostgreSQL server can validate it.

Default: not set.


Which TLS protocol versions are allowed. Allowed values: tlsv1.0, tlsv1.1, tlsv1.2. Shortcuts: all (tlsv1.0,tlsv1.1,tlsv1.2), secure (tlsv1.2), legacy (all).

Default: all


Default: fast


Setting following timeouts cause unexpected errors.


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: 0.0 (disabled)


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]

It also helps when server is down or database rejects connections for any reason. If this is disabled, clients will be queued infinitely.

Default: 120


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: 0.0 (disabled)


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

Default: 0.0 (disabled)



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: 4096


Maximum size for Postgres packets that PgBouncer allows through. One packet is either one query or one resultset row. Full resultset can be larger.

Default: 2147483647


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


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


How many seconds to wait for buffer flush during SUSPEND or reboot (-R). Connection is dropped if flush does not succeed.

Default: 10


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

Default: 45 on Linux, otherwise 0


Default: not set


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


Default: not set


Default: not set


Default: not set


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.


Destination database name.

Default: same as client-side database name.


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.


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.


If auth_user is set, any user not specified in auth_file will be queried from pg_shadow in the database using auth_user. Auth_user\(aqs password will be taken from auth_file.

Direct access to pg_shadow requires admin rights. It\(aqs preferable to use non-admin user that calls SECURITY DEFINER function instead.


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


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.


Set the pool mode specific to this database. If not set, the default pool_mode is used.


Configure a database-wide maximum (i.e. all pools within the database will not have more than this many server connections).


Ask specific client_encoding from server.


Ask specific datestyle from server.


Ask specific timezone from server.


This contains key=value pairs where key will be taken as a user 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.


Set the pool mode to be used for all connections from this user. If not set, the database or default pool_mode is used.


The PgBouncer config file can contain include directives, which specify another config file to read and process. This allows for splitting the configuration file into physically separate parts. The include directives look like this:

%include filename

If the file name is not absolute path it is taken as relative to current working directory.


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/ 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.


It follows the format of PostgreSQL pg_hba.conf file -

There are following differences:
o Supported record types: local, host, hostssl, hostnossl.
o Database field: Supports all, sameuser, @file, multiple names. Not supported: replication, samerole, samegroup.
o Username field: Supports all, @file, multiple names. Not supported: +groupname.
o Address field: Supported IPv4, IPv6. Not supported: DNS names, domain prefixes.
o Auth-method field: Supported methods: trust, reject, md5, password, peer, cert. Not supported: gss, sspi, ident, ldap, radius, pam. Also username map (map=) parameter is not supported.


Minimal config:

template1 = host= dbname=template1 auth_user=someuser

[pgbouncer] pool_mode = session listen_port = 6543 listen_addr = auth_type = md5 auth_file = users.txt logfile = pgbouncer.log pidfile = admin_users = someuser stats_users = stat_collector

Database defaults:


; foodb over unix socket foodb =

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

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

Example of secure function for auth_query:

CREATE OR REPLACE FUNCTION pgbouncer.user_lookup(in i_username text, out uname text, out phash text)
RETURNS record AS $$
    SELECT usename, passwd FROM pg_catalog.pg_shadow
    WHERE usename = i_username INTO uname, phash;
REVOKE ALL ON FUNCTION pgbouncer.user_lookup(text) FROM public, pgbouncer;
GRANT EXECUTE ON FUNCTION pgbouncer.user_lookup(text) TO pgbouncer;


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

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1.7 PGBOUNCER.INI (5) 2006-10-23

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