pgbouncer
pgbouncer — a Postgres Pro connection pooler
Synopsis
On Linux systems:
pgbouncer
[ -d ] [ -R ] [ -v ] [ -u user
] pgbouncer.ini
pgbouncer
-V | -h
On Windows:
pgbouncer
[ -v ] [ -u user
] pgbouncer.ini
pgbouncer
-V | -h
To use pgbouncer as a Windows service:
pgbouncer.exe
--regservice pgbouncer.ini
pgbouncer.exe
--unregservice pgbouncer.ini
Description
pgbouncer is a Postgres Pro connection pooler. Any target application can be connected to pgbouncer as if it were a Postgres Pro 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 Postgres Pro.
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 a 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 a 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 the 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 is as follows.
Create a
pgbouncer.ini
file. Details in thepgbouncer(5)
man page. Simple example:[databases] template1 = host=localhost dbname=template1 auth_user=someuser [pgbouncer] listen_port = 6432 listen_addr = localhost auth_type = md5 auth_file = userlist.txt logfile = pgbouncer.log pidfile = pgbouncer.pid admin_users = someuser
Create a
userlist.txt
file that contains the users allowed in:"someuser" "same_password_as_in_server"
Launch pgbouncer:
$ pgbouncer -d pgbouncer.ini
Note
The above command does not work on Windows systems. Instead, pgbouncer must be launched as a service that first needs to be registered, as follows:
pgbouncer --regservice
Have your application (or the
psql
client) connect to pgbouncer instead of directly to the Postgres Pro server:$ psql -p 6432 -U someuser template1
Manage pgbouncer by connecting to the special administration database pgbouncer and issuing
SHOW HELP;
to begin:$ psql -p 6432 -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 [...]
If you made changes to the
pgbouncer.ini
file, you can reload it with:pgbouncer=# RELOAD;
Options
-d, --daemon
Run in the background. Without it, the process will run in the foreground. In daemon mode, setting
pidfile
as well aslogfile
orsyslog
is required. No log messages will be written to stderr after going into the background.Note
Does not work on Windows, pgbouncer needs to run as service there.
-R, --reboot
Note
This option is deprecated. Instead of this option use a rolling restart with multiple pgbouncer processes listening on the same port using
so_reuseport
instead.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 configuration. Does not work on Windows. Does not work with TLS connections, they are dropped.-u
user
, --useruser
Switch to the given user on startup.
-v, --verbose
Increase verbosity. Can be used multiple times.
-q, --quiet
Be quiet: do not log to stderr. This does not affect logging verbosity, only that stderr is not to be used. For use in
init.d
scripts.-V, --version
Show version.
-h, --help
Show short help.
--regservice
Win32: Register to run as Windows service. The
service_name
configuration parameter value is used as the 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 6432 pgbouncer
Only users listed in the configuration parameters admin_users
or stats_users
are allowed to log in to the console. (Except when auth_mode=any
, then any user is allowed in as a stats_user
.)
Additionally, the user name pgbouncer
is allowed to log in without password, if the login comes via the Unix socket and the client has same Unix user uid as the running process.
The admin console currently only supports the simple query protocol. Some drivers use the extended query protocol for all commands; these drivers will not work for this.
Show Commands
The SHOW
commands output information. Each command is described below.
SHOW STATS
Shows statistics. In this and related commands, the total figures are since process start, the averages are updated every stats_period
.
database
Statistics are presented per database.
total_xact_count
Total number of SQL transactions pooled by pgbouncer.
total_query_count
Total number of SQL queries 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_xact_time
Total number of microseconds spent by pgbouncer when connected to Postgres Pro in a transaction, either idle in transaction or executing queries.
total_query_time
Total number of microseconds spent by pgbouncer when actively connected to Postgres Pro, executing queries.
total_wait_time
Time spent by clients waiting for a server, in microseconds. Updated when a client connection is assigned a backend connection.
avg_xact_count
Average transactions per second in last stat period.
avg_query_count
Average queries 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_xact_time
Average transaction duration, in microseconds.
avg_query_time
Average query duration, in microseconds.
avg_wait_time
Average time spent by clients waiting for a server that were assigned a backend connection within the current
stats_period
, in microseconds (average per second within that period).
SHOW STATS_TOTALS
Subset of SHOW STATS
showing the total values (total_
).
SHOW STATS_AVERAGES
Subset of SHOW STATS
showing the average values (avg_
).
SHOW TOTALS
Like SHOW STATS
but aggregated across all databases.
SHOW SERVERS
type
S, for server.
user
User name pgbouncer uses to connect to server.
database
Database name.
state
State of the pgbouncer server connection, one of
active
,idle
,used
,tested
,new
,active_cancel
, orbeing_canceled
.addr
IP address of Postgres Pro server.
port
Port of Postgres Pro 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.
wait
Not used for server connections.
wait_us
Not used for server connections.
close_needed
1 if the connection will be closed as soon as possible, because a configuration file reload or DNS update changed the connection information or
RECONNECT
was issued.ptr
Address of internal object for this connection. Used as unique ID.
link
Address of client connection the server is paired with.
remote_pid
PID of backend server process. In case connection is made over Unix socket and OS supports getting process ID info, its OS PID. Otherwise it's extracted from cancel packet the server sent, which should be the PID in case the server is Postgres Pro, but it's a random number in case the server is another pgbouncer.
tls
A string with TLS connection information, or empty if not using TLS.
application_name
A string containing the
application_name
set on the linked client connection, or empty if this is not set, or if there is no linked connection.
SHOW CLIENTS
type
C, for client.
user
Client connected user.
database
Database name.
state
State of the client connection, one of
active
,waiting
,active_cancel_req
, orwaiting_cancel_req
.addr
IP address of the client.
port
Source port of the client.
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.
wait
Current waiting time in seconds.
wait_us
Microsecond part of the current waiting time.
close_needed
Not used for clients.
ptr
Address of internal object for this connection. Used as unique ID.
link
Address of server connection the client is paired with.
remote_pid
Process ID, in case client connects over Unix socket and OS supports getting it.
tls
A string with TLS connection information, or empty if not using TLS.
application_name
A string containing the
application_name
set by the client for this connection, or empty if this is not set.
SHOW POOLS
A new pool entry is made for each couple of (database, user).
database
Database name.
user
User name.
cl_active
Client connections that are either linked to server connections or are idle with no queries waiting to be processed.
cl_waiting
Client connections that have sent queries but have not yet got a server connection.
cl_active_cancel_req
Client connections that have forwarded query cancellations to the server and are waiting for the server response.
cl_waiting_cancel_req
Client connections that have not forwarded query cancellations to the server yet.
sv_active
Server connections that are linked to a client.
sv_active_cancel
Server connections that are currently forwarding a cancel request.
sv_being_canceled
Servers that normally could become idle but are waiting to do so until all in-flight cancel requests have completed that were sent to cancel a query on this server.
sv_idle
Server connections that are unused and immediately usable for client queries.
sv_used
Server connections that have been idle for more than
server_check_delay
, so they needserver_check_query
to run on them before they can be used again.sv_tested
Server connections that are currently running either
server_reset_query
orserver_check_query
.sv_login
Server connections currently in the process of logging in.
maxwait
How long the first (oldest) client in the queue has waited, in seconds. If this starts increasing, then the current pool of servers does not handle requests quickly enough. The reason may be either an overloaded server or just too small of a
pool_size
setting.maxwait_us
Microsecond part of the maximum waiting time.
pool_mode
The pooling mode in use.
SHOW PEER_POOLS
A new peer_pool
entry is made for each configured peer.
database
ID of the configured peer entry.
cl_active_cancel_req
Client connections that have forwarded query cancellations to the server and are waiting for the server response.
cl_waiting_cancel_req
Client connections that have not forwarded query cancellations to the server yet.
sv_active_cancel
Server connections that are currently forwarding a cancel request.
sv_login
Server connections currently in the process of logging in.
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.
dns_names
Count of DNS names in the cache.
dns_zones
Count of DNS zones in the cache.
dns_queries
Count of in-flight DNS queries.
dns_pending
Not used.
SHOW USERS
name
The user name.
pool_mode
The user's override
pool_mode
, orNULL
if the default will be used instead.
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 the user is part of the connection string, the connection between pgbouncer and Postgres Pro is forced to the given user, whatever the client user.
pool_size
Maximum number of server connections.
min_pool_size
Minimum number of server connections.
reserve_pool
Maximum number of additional connections for this database.
pool_mode
The database's override pool_mode, or
NULL
if the default will be used instead.max_connections
Maximum number of allowed connections for this database, as set by
max_db_connections
, either globally or per database.current_connections
Current number of connections for this database.
paused
1 if this database is currently paused, else 0.
disabled
1 if this database is currently disabled, else 0.
SHOW PEERS
peer_id
ID of the configured peer entry.
host
Host pgbouncer connects to.
port
Port pgbouncer connects to.
pool_size
Maximum number of server connections that can be made to this peer.
SHOW FDS
Internal command — shows list of file descriptors (FDs) in use with internal state attached to them.
When the connected user has the user name pgbouncer
, connects through the Unix socket and has the same UID as the 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.
This command also blocks the internal event loop, so it should not be used while pgbouncer is in use.
fd
File descriptor numeric value.
task
One of
pooler
,client
orserver
.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
File descriptor for corresponding server/client.
NULL
if idle.
SHOW SOCKETS, SHOW ACTIVE_SOCKETS
Shows low-level information about sockets or only active sockets. This includes the information shown under SHOW CLIENTS
and SHOW SERVERS
as well as other more low-level information.
SHOW CONFIG
Show the current configuration settings, one per row, with the following columns:
key
Configuration variable name.
value
Configuration value.
default
Configuration default value.
changeable
Either
yes
orno
, shows if the variable can be changed while running. Ifno
, the variable can be changed only at boot-time. UseSET
to change a variable at run time.
SHOW MEM
Shows low-level information about the current sizes of various internal memory allocations. The information presented is subject to change.
SHOW DNS_HOSTS
Show host names in DNS cache.
hostname
Host name.
ttl
How many 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
Host names belonging to this zone.
SHOW VERSION
Show the pgbouncer version string.
SHOW STATE
Show the pgbouncer state settings. Current states are active, paused and suspended.
Process Controlling Commands
PAUSE [db
]
pgbouncer tries to disconnect from all servers. Disconnecting each server connection waits for that server connection to be released according to the server pool's pooling mode (in transaction pooling mode, the transaction must complete, in statement mode, the statement must complete, and in session pooling mode the client must disconnect). The command will not return before all server connections have been disconnected. To be used at the time of database restart.
If database name is given, only that database will be paused.
New client connections to a paused database will wait until RESUME
is called.
DISABLE db
Reject all new client connections on the given database.
ENABLE db
Allow new client connections after a previous DISABLE
command.
RECONNECT db
Close each open server connection for the given database, or all databases, after it is released (according to the pooling mode), even if its lifetime is not up yet. New server connections can be made immediately and will connect as necessary according to the pool size settings.
This command is useful when the server connection setup has changed, for example to perform a gradual switchover to a new server. It is not necessary to run this command when the connection string in pgbouncer.ini
has been changed and reloaded (see RELOAD
) or when DNS resolution has changed, because then the equivalent of this command will be run automatically. This command is only necessary if something downstream of pgbouncer routes the connections.
After this command is run, there could be an extended period where some server connections go to an old destination and some server connections go to a new destination. This is likely only sensible when switching read-only traffic between read-only replicas, or when switching between nodes of a multimaster replication setup. If all connections need to be switched at the same time, PAUSE
is recommended instead. To close server connections without waiting (for example, in emergency failover rather than gradual switchover scenarios), also consider KILL
.
KILL db
Immediately drop all client and server connections on given database.
New client connections to a killed database will wait until RESUME
is called.
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.
New client connections to a suspended database will wait until RESUME
is called.
RESUME [db
]
Resume work from previous KILL
, PAUSE
, or SUSPEND
command.
SHUTDOWN
The pgbouncer process will exit.
RELOAD
The pgbouncer process will reload its configuration files and update changeable settings. This includes the main configuration file as well as the files specified by the settings auth_file
and auth_hba_file
.
pgbouncer notices when a configuration file reload changes the connection parameters of a database definition. An existing server connection to the old destination will be closed when the server connection is next released (according to the pooling mode), and new server connections will immediately use the updated connection parameters.
WAIT_CLOSE [db
]
Wait until all server connections, either of the specified database or of all databases, have cleared the close_needed
state (see the section called “SHOW SERVERS”). This can be called after a RECONNECT
or RELOAD
to wait until the respective configuration change has been fully activated, for example in switchover scripts.
Other Commands
SET key
= arg
Changes a configuration setting (see also the section called “SHOW CONFIG”). For example:
SET log_connections = 1; SET server_check_query = 'select 2';
(Note that this command is run on the pgbouncer admin console and sets pgbouncer settings. A SET
command run on another database will be passed to the Postgres Pro backend like any other SQL command.)
Signals
SIGHUP
Reload config. Same as issuing the command
RELOAD
on the console.SIGINT
Safe shutdown. Same as issuing
PAUSE
andSHUTDOWN
on the console.SIGTERM
Immediate shutdown. Same as issuing
SHUTDOWN
on the console.SIGUSR1
Same as issuing
PAUSE
on the console.SIGUSR2
Same as issuing
RESUME
on the console.
Libevent Settings
From the libevent documentation:
It is possible to disable support for
epoll
,kqueue
,devpoll
,poll
, orselect
by setting the environment variableEVENT_NOEPOLL
,EVENT_NOKQUEUE
,EVENT_NODEVPOLL
,EVENT_NOPOLL
orEVENT_NOSELECT
, respectively.By setting the environment variable
EVENT_SHOW_METHOD
,libevent
displays the kernel notification method that it uses.
pgbouncer.ini
Configuration File
The configuration file is in the .ini
format. Section names are between [
and ]
. Lines starting with ;
or #
are taken as comments and ignored. The characters ;
and #
are not recognized as special when they appear later in the line.
Generic Settings
logfile
Specifies the log file. For daemonization (
-d
), either this orsyslog
has to be set. The log file is kept open, so after rotation,kill -HUP
or on consoleRELOAD;
should be done. On Windows, the service must be stopped and started.Note that setting
logfile
does not by itself turn off logging to stderr. Use the command-line option-q
or-d
for that.Default: not set
pidfile
Specifies the PID file. Without
pidfile
set, daemonization (-d
) is not allowed.Default: not set
listen_addr
Specifies a list (comma-separated) 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 accepted.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 the location for Unix sockets. Applies to both the listening socket and server connections. If set to an empty string, Unix sockets are disabled. A value that starts with
@
specifies that a Unix socket in the abstract namespace should be created (currently supported on Linux and Windows).For online reboot (
-R
) to work, a Unix socket needs to be configured, and it needs to be in the file-system namespace.Default:
/tmp
(empty on Windows)unix_socket_mode
File system mode for Unix socket. Ignored for sockets in the abstract namespace. Not supported on Windows.
Default: 0777
unix_socket_group
Group name to use for Unix socket. Ignored for sockets in the abstract namespace. Not supported on Windows.
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 it's already running as the given user.
Not supported on Windows.
Default: not set
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. Transactions spanning multiple statements are disallowed in this mode.
max_client_conn
Maximum number of client connections allowed.
When this setting is increased, then the file descriptor limits in the operating system might also have to be increased. Note that the number of file descriptors potentially used is more than
max_client_conn
. If each user connects under its own username to the server, the theoretical maximum used is:max_client_conn + (max pool_size * total databases * total users)
If a database user is specified in the connection string (all users connect under the same user name), the theoretical maximum is:
max_client_conn + (max pool_size * total databases)
The theoretical maximum should never be reached, unless somebody deliberately crafts a 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 favorite 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 the behavior when the normal load suddenly comes back after a period of total inactivity. The value is effectively capped at the pool size.
Default: 0 (disabled)
reserve_pool_size
How many additional connections to allow to a pool (see
reserve_pool_timeout
). The 0 value disables this parameter.Default: 0 (disabled)
reserve_pool_timeout
If a client has not been serviced in this time, pgbouncer enables use of additional connections from the reserve pool. The 0 value disables this parameter. [seconds]
Default: 5.0
max_db_connections
Do not allow more than this many server connections per database (regardless of user). This considers the pgbouncer database that the client has connected to, not the Postgres Pro database of the outgoing connection. This can also be set per database in the
[databases]
section.Note 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: 0 (unlimited)
max_user_connections
Do not allow more than this many server connections per user (regardless of database). This considers the pgbouncer user that is associated with a pool, which is either the user specified for the server connection or in absence of that the user the client has connected as. This can also be set per user in the
[users]
section.Note 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: 0 (unlimited)
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 a round-robin system behind a database address (TCP, DNS, or host list), then it is better if pgbouncer also uses connections in that manner, thus achieving uniform load.
Default: 0
track_extra_parameters
By default, pgbouncer tracks
client_encoding
,datestyle
,timezone
,standard_conforming_strings
andapplication_name
parameters per client. To allow other parameters to be tracked, they can be specified here, so that pgbouncer knows that they should be maintained in the client variable cache and restored in the server whenever the client becomes active.If you need to specify multiple values, use a comma-separated list (e.g.
default_transaction_readonly, IntervalStyle
)Note
Most parameters cannot be tracked this way. The only parameters that can be tracked are ones that Postgres Pro reports to the client. Postgres Pro has an official list of parameters that it reports to the client. Postgres Pro extensions can change this list though, they can add parameters themselves that they also report, and they can start reporting already existing paremeters that Postgres Pro does not report. Notably Citus 12.0+ causes PostgreSQL to also report
search_path
.The
postgres
protocol allows specifying parameter settings, both directly as a parameter in the startup packet, or inside theoptions
startup packet. Parameters specified using both of these methods are supported bytrack_extra_parameters
. However, it's not possible to includeoptions
itself intrack_extra_parameters
, only the parameters contained inoptions
.Default:
IntervalStyle
ignore_startup_parameters
By default, pgbouncer allows only parameters it can keep track of in startup packets:
client_encoding
,datestyle
,timezone
andstandard_conforming_strings
.All other parameters will raise an error. To allow other parameters, they can be specified here, so that pgbouncer knows that they are handled by the admin and it can ignore them.
If you need to specify multiple values, use a comma-separated list (e.g.
options,extra_float_digits
).The
postgres
protocol allows specifying parameter settings, both directly as a parameter in the startup packet, or inside theoptions
startup packet. Parameters specified using both of these methods are supported byignore_startup_parameters
. It's even possible to includeoptions
itself inignore_startup_parameters
, which results in any unknown parameters contained insideoptions
to be ignored.Default: empty
peer_id
The peer ID used to identify this pgbouncer process in a group of pgbouncer processes that are peered together. The
peer_id
value should be unique within a group of peered pgbouncer processes. When set to 0, pgbouncer peering is disabled. See also [peers] Section for more information. The maximum value that can be used for thepeer_id
is 16383.Default: 0
disable_pqexec
Disable the Simple Query protocol (PQexec). Unlike the 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 the Extended Query protocol will stay working.
Default: 0
application_name_add_host
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 at the start of a connection. If
application_name
is later changed withSET
, pgbouncer does not change it again.Default: 0
conffile
Show location of current configuration file. Changing it will make pgbouncer use another configuration file for next
RELOAD
/SIGHUP
.Default: file from command line
service_name
Used on win32 service registration.
Default:
pgbouncer
job_name
Alias for
service_name
.stats_period
Sets how often the averages shown in various
SHOW
commands are updated and how often aggregated statistics are written to the log (but seelog_stats
). [seconds]Default: 60
Authentication Settings
pgbouncer handles its own client authentication and has its own database of users. These settings control this.
auth_type
How to authenticate users.
cert
The client must connect over TLS connection with a valid client certificate. The user name is then taken from the
CommonName
field from the certificate.md5
Use MD5-based password check. This is the default authentication method.
auth_file
may contain both MD5-encrypted and plain-text passwords. Ifmd5
is configured and a user has a SCRAM secret, then SCRAM authentication is used automatically instead.scram-sha-256
Use password check with SCRAM-SHA-256.
auth_file
has to contain SCRAM secrets or plain-text passwords. Note that SCRAM secrets can only be used for verifying the password of a client but not for logging into a server. To be able to use SCRAM on server connections, use plain-text passwords.plain
The clear-text password is sent over the wire. Deprecated.
trust
No authentication is done. The user name must still exist in
auth_file
.any
Like the
trust
method, but the user name given is ignored. Requires that all databases are configured to log in as a specific user. Additionally, the console database allows any user to log in as admin.hba
The actual authentication type is loaded from
auth_hba_file
. This allows different authentication methods for different access paths, for example: connections over Unix socket usepeer
authentication method, connections over TCP must use TLS.pam
Pluggable Authentication Modules (PAM) method is used to authenticate users,
auth_file
is ignored. This method is not compatible with databases using theauth_user
option. The service name reported to PAM ispgbouncer
.pam
is not supported in the HBA configuration file.
auth_hba_file
HBA configuration file to use when
auth_type
ishba
.Default: not set
auth_file
The name of the file to load user names and passwords from. See the section called “Authentication File Format” for details.
Most authentication types (see
auth_type
) require that eitherauth_file
orauth_user
be set; otherwise there would be no users defined.Default: not set
auth_user
If
auth_user
is set, then any user not specified inauth_file
will be queried through theauth_query
query frompg_shadow
in the database, usingauth_user
. The password ofauth_user
will be taken fromauth_file
. (Ifauth_user
does not require a password, then it does not need to be defined inauth_file
.)Direct access to
pg_shadow
requires admin rights. It's preferable to use a non-superuser that calls aSECURITY DEFINER
function instead.Default: not set
auth_query
Query to load user's password from database.
Direct access to
pg_shadow
requires admin rights. It's preferable to use a non-superuser that calls aSECURITY DEFINER
function instead.Note that the query is run inside the target database. So if a function is used, it needs to be installed into each database.
Default:
SELECT usename, passwd FROM pg_shadow WHERE usename=$1
auth_dbname
Database name in the [databases] section to be used for authentication purposes. This option can be either global or overriden in the connection string if this parameter is specified.
Log Settings
syslog
Toggles syslog on/off. On Windows, the event log 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 the pooler sends to clients.
Default: 1
log_stats
Write aggregated statistics into the log, every
stats_period
. This can be disabled if external monitoring tools are used to grab the same data fromSHOW
commands.Default: 1
verbose
Increase verbosity. Mirrors the
-v
switch on the command line. For example, using-v -v
on the command line is the same asverbose=2
.Default: 0
Console Access Control
admin_users
Comma-separated list of database users that are allowed to connect and run all commands on the console. Ignored when
auth_type
isany
, in which case any user name 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 the console. That means all
SHOW
commands exceptSHOW 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 the value should not include
ABORT
orROLLBACK
.The query is supposed to clean any changes made to the database session so that the next client gets the connection in a well-defined state. The default is
DISCARD ALL
, which cleans everything, but that leaves the next client no pre-cached state. It can be made lighter, e.g.DEALLOCATE ALL
to just drop prepared statements, if the application does not break when some state is kept around.When transaction pooling is used, the
server_reset_query
is not used, because in that mode, clients must not use any session-based features, since each transaction ends up in a different connection and thus gets a different session state.Default:
DISCARD ALL
server_reset_query_always
Whether
server_reset_query
should be run in all pooling modes. When this setting is off (default), theserver_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 a reset query.This setting is for working around broken setups that run applications that use session features over a transaction-pooled pgbouncer. It changes non-deterministic breakage to deterministic breakage: clients always lose their state after each transaction.
Default: 0
server_check_delay
How long to keep released connections available for immediate re-use, without running
server_check_query
on it. If 0 then the query is always run.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_fast_close
Disconnect a server in session pooling mode immediately or after the end of the current transaction if it is in
close_needed
mode (set byRECONNECT
,RELOAD
that changes connection settings, or DNS change), rather than waiting for the session end. In statement or transaction pooling mode, this has no effect since that is the default behavior there.If because of this setting a server connection is closed before the end of the client session, the client connection is also closed. This ensures that the client notices that the session has been interrupted.
This setting makes connection configuration changes take effect sooner if session pooling and long-running sessions are used. The downside is that client sessions are liable to be interrupted by a configuration change, so client applications will need logic to reconnect and reestablish session state. But note that no transactions will be lost, because running transactions are not interrupted, only idle sessions.
Default: 0
server_lifetime
The pooler will close an unused (not currently linked to any client connection) server connection that has 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 closed. If 0 then timeout is disabled. [seconds]
Default: 600.0
server_connect_timeout
If connection and login don't finish in this amount of time, the connection will be closed. [seconds]
Default: 15.0
server_login_retry
If login to the server failed, because of failure to connect or from authentication, the pooler waits this much before retrying to connect. During the waiting interval, new clients trying to connect to the failing server will get an error immediately without another connection attempt. [seconds]
The purpose of this behavior is that clients don't unnecessarily queue up waiting for a server connection to become available if the server is not working. However, it also means that if a server is momentarily failing, for example during a restart or if the configuration was erroneous, then it will take at least this long until the pooler will consider connecting to it again. Planned events such as restarts should normally be managed using the
PAUSE
command to avoid this.Default: 15.0
client_login_timeout
If a client connects but does not manage to log in 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 DNS lookups can be cached. The actual DNS TTL is ignored. [seconds]
Default: 15.0
dns_nxdomain_ttl
How long DNS errors and
NXDOMAIN
DNS lookups can be cached. [seconds]Default: 15.0
dns_zone_check_period
Period to check if a zone serial has changed.
pgbouncer can collect DNS zones from host names (everything after first dot) and then periodically check if the zone serial changes. If it notices changes, all host names under that zone are looked up again. If any host IP changes, its connections are invalidated.
Default: 0.0 (disabled)
resolv_conf
The location of a custom
resolv.conf
file. This is to allow specifying custom DNS servers and perhaps other name resolution options, independent of the global operating system configuration.The parsing of the file is done by the DNS backend library, not pgbouncer, so see the library's documentation for details on allowed syntax and directives.
Default: empty (use operating system defaults)
TLS Settings
client_tls_sslmode
TLS mode to use for connections from clients. TLS connections are disabled by default. When enabled,
client_tls_key_file
andclient_tls_cert_file
must be also configured to set up the key and certificate pgbouncer uses to accept client connections.disable
Plain TCP. If client requests TLS, it's ignored. Default.
allow
If client requests TLS, it is used. If not, plain TCP is used. If the client presents a client certificate, it is not validated.
prefer
Same as
allow
.require
The client must use TLS. If not, the client connection is rejected. If the client presents a client certificate, it is not validated.
verify-ca
Client must use TLS with valid client certificate.
verify-full
Same as
verify-ca
.
client_tls_key_file
Private key for pgbouncer to accept client connections.
Default: not set
client_tls_cert_file
Certificate for private key. Clients can validate it.
Default: not set
client_tls_ca_file
Root certificate file to validate client certificates.
Default: not set
client_tls_protocols
Which TLS protocol versions are allowed. Allowed values:
tlsv1.0
,tlsv1.1
,tlsv1.2
,tlsv1.3
. Shortcuts:all
(tlsv1.0,tlsv1.1,tlsv1.2,tlsv1.3),secure
(tlsv1.2,tlsv1.3),legacy
(all).Default:
secure
client_tls_ciphers
Allowed TLS ciphers, in OpenSSL syntax. Shortcuts:
default
/secure
,compat
/legacy
,insecure
/all
,normal
,fast
.Only connections using TLS version 1.2 and lower are affected. There is currently no setting that controls the cipher choices used by TLS version 1.3 connections.
Default:
fast
client_tls_ecdhcurve
Elliptic Curve name to use for ECDH key exchanges.
Allowed values:
none
(DH is disabled),auto
(256-bit ECDH), curve name.Default:
auto
client_tls_dheparams
DHE key exchange type.
Allowed values:
none
(DH is disabled),auto
(2048-bit DH),legacy
(1024-bit DH).Default:
auto
server_tls_sslmode
TLS mode to use for connections to Postgres Pro servers. The default mode is
prefer
.disable
Plain TCP. TLS is not even requested from the server.
prefer
TLS connection is always requested first from Postgres Pro. If refused, the connection will be established over plain TCP. Server certificate is not validated. Default.
require
Connection must go over TLS. If server rejects it, plain TCP is not attempted. Server certificate is not validated.
verify-ca
Connection must go over TLS and server certificate must be valid according to
server_tls_ca_file
. Server host name is not checked against certificate.verify-full
Connection must go over TLS and server certificate must be valid according to
server_tls_ca_file
. Server host name must match certificate information.
server_tls_ca_file
Root certificate file to validate Postgres Pro server certificates.
Default: not set
server_tls_key_file
Private key for pgbouncer to authenticate against Postgres Pro server.
Default: not set
server_tls_cert_file
Certificate for private key. Postgres Pro server can validate it.
Default: not set
server_tls_protocols
Which TLS protocol versions are allowed. Allowed values:
tlsv1.0
,tlsv1.1
,tlsv1.2
,tlsv1.3
. Shortcuts:all
(tlsv1.0,tlsv1.1,tlsv1.2,tlsv1.3),secure
(tlsv1.2,tlsv1.3),legacy
(all).Default:
secure
server_tls_ciphers
Allowed TLS ciphers, in OpenSSL syntax. Shortcuts:
default
/secure
,compat
/legacy
,insecure
/all
,normal
,fast
.Only connections using TLS version 1.2 and lower are affected. There is currently no setting that controls the cipher choices used by TLS version 1.3 connections.
Default:
fast
Dangerous Timeouts
Setting the following timeouts can cause unexpected errors.
query_timeout
Queries running longer than that are canceled. This should be used only with a 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. The 0 value disables this parameter. If this is disabled, clients will be queued indefinitely. [seconds]
This setting is used to prevent unresponsive servers from grabbing up connections. It also helps when the server is down or rejects connections for any reason.
Default: 120.0
cancel_wait_timeout
Maximum time cancellation requests are allowed to spend waiting for execution. If the cancel request is not assigned to a server during that time, the client is disconnected. 0 disables. If this is disabled, cancel requests will be queued indefinitely. [seconds]
This setting is used to prevent a client locking up when a cancel cannot be forwarded due to the server being down.
Default: 10.0
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 a client has been in the “idle in transaction” state longer, it will be disconnected. [seconds]
Default: 0.0 (disabled)
suspend_timeout
How long to wait for buffer flush during
SUSPEND
or reboot (-R
). A connection is dropped if the flush does not succeed. [seconds]Default: 10
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: 4096
max_packet_size
Maximum size for Postgres Pro packets that pgbouncer allows through. One packet is either one query or one result set row. The full result set can be larger.
Default: 2147483647
listen_backlog
The value of the
backlog
argument forlisten()
. Determines how many new unanswered connection attempts are kept in the queue. When the 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 result set can stall pgbouncer for a long time. One loop processes one
pkt_buf
amount of data. 0 means no limit.Default: 5
so_reuseport
Specifies whether to set the socket option
SO_REUSEPORT
on TCP listening sockets. On some operating systems, this allows running multiple pgbouncer instances on the same host listening on the same port and having the kernel distribute the connections automatically. This option is a way to get pgbouncer to use more CPU cores. (pgbouncer is single-threaded and uses one CPU core per instance.)This setting has the desired effect on Linux. On systems that don't support the socket option at all, turning this setting on will result in an error.
Each pgbouncer instance on the same host needs different settings for at least
unix_socket_dir
andpidfile
, as well aslogfile
if that is used. Also note that if you make use of this option, you can no longer connect to a specific pgbouncer instance via TCP/IP, which might have implications for monitoring and metrics collection.To make sure query cancellations keep working, you should set up pgbouncer peering between the different pgbouncer processes. For details see the
peer_id
configuration option and the[peers]
configuration section. There's also an example that uses peering andso_reuseport
in the Examples section.Default: 0
tcp_defer_accept
Sets the
TCP_DEFER_ACCEPT
socket option; seeman 7 tcp
for details. (This is a Boolean option: 1 means enabled. The actual value set if enabled is currently hardcoded to 45 seconds.)This is currently only supported on Linux.
Default: 1 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 operating systems.
Default: 1
tcp_keepcnt
Default: not set
tcp_keepidle
Default: not set
tcp_keepintvl
Default: not set
tcp_user_timeout
Sets the
TCP_USER_TIMEOUT
socket option. This specifies the maximum amount of time in milliseconds that transmitted data may remain unacknowledged before the TCP connection is forcibly closed. If set to 0, then operating system's default is used.This is currently only supported on Linux.
Default: 0
Section [databases]
The section [databases]
defines the names of the databases that clients of pgbouncer can connect to and specifies where those connections will be routed. The section contains key=value lines like
dbname = connection string
where the key will be taken as a database name and the value as a connection string, consisting of key=value pairs of connection parameters, described below (similar to libpq, but the actual libpq is not used and the set of available features is different).
Example:
foodb = host=host1.example.com port=5432 bardb = host=localhost dbname=bazdb
The 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.
The database name pgbouncer
is reserved for the admin console and cannot be used as a key here.
*
acts as fallback database: if the exact name does not exist, its value is taken as connection string for the requested database. For example, if there is the following entry (and no other overriding entries):
* = host=foo
In this case, a connection to pgbouncer specifying a database bar
will effectively behave as if the following entry exists (taking advantage of the default for dbname
being the client-side database name):
bar = host=foo dbname=bar
Such automatically created database entries are cleaned up if they stay idle longer than the time specified by the autodb_idle_timeout
parameter.
dbname
Destination database name.
Default: same as client-side database name
host
Host name or IP address to connect to. Host names are resolved at connection time, the result is cached per
dns_max_ttl
parameter. When a host name's resolution changes, existing server connections are automatically closed when they are released (according to the pooling mode), and new server connections immediately use the new resolution. If DNS returns several results, they are used in a round-robin manner.If the value begins with
/
, then a Unix socket in the file-system namespace is used. If the value begins with@
, then a Unix socket in the abstract namespace is used.A comma-separated list of host names or addresses can be specified. In that case, connections are made in a round-robin manner. (If a host list contains host names that in turn resolve via DNS to multiple addresses, the round-robin systems operate independently. This is an implementation dependency that is subject to change.) Note that in a list, all hosts must be available at all times: there are no mechanisms to skip unreachable hosts or to select only available hosts from a list or similar. (This is different from what a host list in libpq means.) Also note that this only affects how the destinations of new connections are chosen. See also the setting
server_round_robin
for how clients are assigned to already established server connections.Examples:
host=localhost host=127.0.0.1 host=2001:0db8:85a3:0000:0000:8a2e:0370:7334 host=/var/run/postgresql host=192.168.0.1,192.168.0.2,192.168.0.3
Default: not set, meaning to use a Unix socket
port
Default: 5432
user
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 logs into the destination database with the client user name, meaning that there will be one pool per user.
password
If no password is specified here, the password from the
auth_file
orauth_query
will be used.auth_user
Override of the global
auth_user
setting, if specified.pool_size
Set the maximum size of pools for this database. If not set, the
default_pool_size
is used.min_pool_size
Set the minimum pool size for this database. If not set, the global
min_pool_size
is used.reserve_pool
Set additional connections for this database. If not set,
reserve_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.
pool_mode
Set the pool mode specific to this database. If not set, the default
pool_mode
is used.max_db_connections
Configure a database-wide maximum (i.e. all pools within the database will not have more than this many server connections).
client_encoding
Ask specific
client_encoding
from server.datestyle
Ask specific
datestyle
from server.timezone
Ask specific
timezone
from server.
Section [users]
This section contains key=value lines like
user1 = settings
where the key will be taken as a user name and the value as a list of configuration settings specific for this user.
Example:
user1 = pool_mode=session
Only a few settings are available here.
pool_mode
Set the pool mode to be used for all connections from this user. If not set, the database or default
pool_mode
is used.max_user_connections
Configure a maximum for the user (i.e. all pools with the user will not have more than this many server connections).
Section [peers]
This section defines the peers that pgbouncer can forward cancellation requests to and where those cancellation requests will be routed.
pgbouncer processes can be peered together in a group by defining a peer_id
value and a [peers]
section in the configs of all the pgbouncer processes. These pgbouncer processes can then forward cancellation requests to the process that it originated from. This is needed to make cancellations work when multiple pgbouncer processes (possibly on different servers) are behind the same TCP load balancer. Cancellation requests are sent over different TCP connections than the query they are cancelling, so a TCP load balancer might send the cancellation request connection to a different process than the one that it was meant for. By peering them these cancellation requests eventually end up at the right process.
The section contains key=value lines like
peer_id = connection string
where the key will be taken as a peer_id
and the value as a connection string, consisting of key=value pairs of connection parameters, described below (similar to libpq, but the actual libpq is not used and the set of available features is different).
Example:
1 = host=host1.example.com 2 = host=/tmp/pgbouncer-2 port=5555
Note
For peering to work, the peer_id
of each pgbouncer process in the group must be unique within the peered group. And the [peers]
section should contain entries for each of those peer IDs. An example can be found in the Examples section. It is allowed, but not necessary, for the [peers]
section to contain the peer_id
of the pgbouncer that the config is for. Such an entry will be ignored, but it is allowed to make config management easier. Because it allows using the exact same [peers]
section for multiple configs.
host
Host name or IP address to connect to. Host names are resolved at connection time, the result is cached per
dns_max_ttl
parameter. If DNS returns several results, they are used in a round-robin manner. But in general it's not recommended to use a hostname that resolves to multiple IPs, because then the cancel request might still be forwarded to the wrong node and it would need to be forwarded again (which is only allowed up to three times).If the value begins with
/
, then a Unix socket in the file-system namespace is used. If the value begins with@
, then a Unix socket in the abstract namespace is used.Examples:
host=localhost host=127.0.0.1 host=2001:0db8:85a3:0000:0000:8a2e:0370:7334 host=/var/run/pgbouncer-1
port
Default: 6432
pool_size
If not set, the
default_pool_size
is used.
Include Directive
The pgbouncer configuration file can contain include directives, which specify another configuration file to read and process. This allows splitting the configuration file into physically separate parts. The include directives look like this:
%include filename
If the filename is not an absolute path, it is taken as relative to the current working directory.
Authentication File Format
This section describes the format of the file specified by the auth_file
setting. It is a text file in the following format:
"username1" "password" ... "username2" "md5abcdef012342345" ... "username2" "SCRAM-SHA-256$iterations
:salt
$storedkey
:serverkey
"
There should be at least two fields, surrounded by double quotes. The first field is the user name and the second is either a plain-text, a MD5-hashed password, or a SCRAM secret. pgbouncer ignores the rest of the line. Double quotes in a field value can be escaped by writing two double quotes.
Postgres Pro MD5-hashed password format:
"md5" + md5(password + username)
So user admin
with password 1234
will have MD5-hashed password md545f2603610af569b6155c45067268c6b
.
Postgres Pro SCRAM secret format:
SCRAM-SHA-256$iterations
:salt
$storedkey
:serverkey
The passwords or secrets stored in the authentication file serve two purposes. First, they are used to verify the passwords of incoming client connections, if a password-based authentication method is configured. Second, they are used as the passwords for outgoing connections to the backend server, if the backend server requires password-based authentication (unless the password is specified directly in the database's connection string). The latter works if the password is stored in plain text or MD5-hashed. SCRAM secrets can only be used for logging into a server if the client authentication also uses SCRAM, the pgbouncer database definition does not specify a user name, and the SCRAM secrets are identical in pgbouncer and the Postgres Pro server (same salt and iterations, not merely the same password). This is due to an inherent security property of SCRAM: the stored SCRAM secret cannot by itself be used for deriving login credentials.
The authentication file can be written by hand, but it's also useful to generate it from some other list of users and passwords. See ./etc/mkauth.py
for a sample script to generate the authentication file from the pg_shadow
system table.
Alternatively, use auth_query
instead of auth_file
to avoid having to maintain a separate authentication file.
HBA File Format
The location of the HBA file is specified by the setting auth_hba_file
. It is only used if auth_type
is set to hba
.
The file follows the format of the Postgres Pro pg_hba.conf
file described in Section 20.1.
Supported record types:
local
,host
,hostssl
,hostnossl
.Database field: Supports
all
,sameuser
, @file
, multiple names. Not supported:replication
,samerole
,samegroup
.User name field: Supports
all
, @file
, multiple names. Not supported:+groupname
.Address field: Supports
IPv4
,IPv6
. Not supported: DNS names, domain prefixes.Auth-method field: Only methods supported by pgbouncer's
auth_type
are supported, pluspeer
andreject
, but exceptany
andpam
, which only work globally. User name map (map=
) parameter is not supported.
Examples
Small example configuration:
[databases] template1 = host=localhost dbname=template1 auth_user=someuser [pgbouncer] pool_mode = session listen_port = 6432 listen_addr = localhost auth_type = md5 auth_file = users.txt logfile = pgbouncer.log pidfile = pgbouncer.pid admin_users = someuser stats_users = stat_collector
Database examples:
[databases] ; foodb over Unix socket foodb = ; redirect bardb to bazdb on localhost bardb = host=localhost dbname=bazdb ; access to destination database will go with single user forcedb = host=localhost port=300 user=baz password=foo client_encoding=UNICODE datestyle=ISO
Example of a 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 $$ BEGIN SELECT usename, passwd FROM pg_catalog.pg_shadow WHERE usename = i_username INTO uname, phash; RETURN; END;$$ LANGUAGE plpgsql SECURITY DEFINER; REVOKE ALL ON FUNCTION pgbouncer.user_lookup(text) FROM public, pgbouncer; GRANT EXECUTE ON FUNCTION pgbouncer.user_lookup(text) TO pgbouncer;
Example configs for 2 peered pgbouncer processes to create a multi-core pgbouncer setup using so_reuseport
.
The config for the first process:
[databases] postgres = host=localhost dbname=postgres [peers] 1 = host=/tmp/pgbouncer1 2 = host=/tmp/pgbouncer2 [pgbouncer] listen_addr=127.0.0.1 auth_file=auth_file.conf so_reuseport=1 unix_socket_dir=/tmp/pgbouncer1 peer_id=1
The config for the second process:
[databases] postgres = host=localhost dbname=postgres [peers] 1 = host=/tmp/pgbouncer1 2 = host=/tmp/pgbouncer2 [pgbouncer] listen_addr=127.0.0.1 auth_file=auth_file.conf so_reuseport=1 ; only unix_socket_dir and peer_id are different unix_socket_dir=/tmp/pgbouncer2 peer_id=2