= 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: 5.0

==== 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: 30.0

==== 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: 3600.0

==== server_idle_timeout ====

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

==== server_connect_timeout ====

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

Default: 15.0

==== server_login_retry ====

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

Default: 15.0

==== 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: 60.0

==== 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: 3600.0

==== 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: 15.0

==== 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: 0.0 (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: 0.0 (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: 0.0 (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: 0.0 (disabled)

==== idle_transaction_timeout ====

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

Default: 0.0 (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

==== max_packet_size ====

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

==== 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[]

