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.inifile. 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.txtfile 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
psqlclient) 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.inifile, you can reload it with:pgbouncer=# RELOAD;
Options
-d, --daemonRun in the background. Without it, the process will run in the foreground. In daemon mode, setting
pidfileas well aslogfileorsyslogis 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, --rebootNote
This option is deprecated. Instead of this option use a rolling restart with multiple pgbouncer processes listening on the same port using
so_reuseportinstead.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_diris not disabled in configuration. Does not work on Windows. Does not work with TLS connections, they are dropped.-uuser, --useruserSwitch to the given user on startup.
-v, --verboseIncrease verbosity. Can be used multiple times.
-q, --quietBe quiet: do not log to stderr. This does not affect logging verbosity, only that stderr is not to be used. For use in
init.dscripts.-V, --versionShow version.
-h, --helpShow short help.
--regserviceWin32: Register to run as Windows service. The
service_nameconfiguration parameter value is used as the name to register under.--unregserviceWin32: 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.
databaseStatistics are presented per database.
total_xact_countTotal number of SQL transactions pooled by pgbouncer.
total_query_countTotal number of SQL queries pooled by pgbouncer.
total_receivedTotal volume in bytes of network traffic received by pgbouncer.
total_sentTotal volume in bytes of network traffic sent by pgbouncer.
total_xact_timeTotal number of microseconds spent by pgbouncer when connected to Postgres Pro in a transaction, either idle in transaction or executing queries.
total_query_timeTotal number of microseconds spent by pgbouncer when actively connected to Postgres Pro, executing queries.
total_wait_timeTime spent by clients waiting for a server, in microseconds. Updated when a client connection is assigned a backend connection.
avg_xact_countAverage transactions per second in last stat period.
avg_query_countAverage queries per second in last stat period.
avg_recvAverage received (from clients) bytes per second.
avg_sentAverage sent (to clients) bytes per second.
avg_xact_timeAverage transaction duration, in microseconds.
avg_query_timeAverage query duration, in microseconds.
avg_wait_timeAverage 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
typeS, for server.
userUser name pgbouncer uses to connect to server.
databaseDatabase name.
stateState of the pgbouncer server connection, one of
active,idle,used,tested,new,active_cancel, orbeing_canceled.addrIP address of Postgres Pro server.
portPort of Postgres Pro server.
local_addrConnection start address on local machine.
local_portConnection start port on local machine.
connect_timeWhen the connection was made.
request_timeWhen last request was issued.
waitNot used for server connections.
wait_usNot used for server connections.
close_needed1 if the connection will be closed as soon as possible, because a configuration file reload or DNS update changed the connection information or
RECONNECTwas issued.ptrAddress of internal object for this connection. Used as unique ID.
linkAddress of client connection the server is paired with.
remote_pidPID 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.
tlsA string with TLS connection information, or empty if not using TLS.
application_nameA string containing the
application_nameset on the linked client connection, or empty if this is not set, or if there is no linked connection.
SHOW CLIENTS
typeC, for client.
userClient connected user.
databaseDatabase name.
stateState of the client connection, one of
active,waiting,active_cancel_req, orwaiting_cancel_req.addrIP address of the client.
portSource port of the client.
local_addrConnection end address on local machine.
local_portConnection end port on local machine.
connect_timeTimestamp of connect time.
request_timeTimestamp of latest client request.
waitCurrent waiting time in seconds.
wait_usMicrosecond part of the current waiting time.
close_neededNot used for clients.
ptrAddress of internal object for this connection. Used as unique ID.
linkAddress of server connection the client is paired with.
remote_pidProcess ID, in case client connects over Unix socket and OS supports getting it.
tlsA string with TLS connection information, or empty if not using TLS.
application_nameA string containing the
application_nameset 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).
databaseDatabase name.
userUser name.
cl_activeClient connections that are either linked to server connections or are idle with no queries waiting to be processed.
cl_waitingClient connections that have sent queries but have not yet got a server connection.
cl_active_cancel_reqClient connections that have forwarded query cancellations to the server and are waiting for the server response.
cl_waiting_cancel_reqClient connections that have not forwarded query cancellations to the server yet.
sv_activeServer connections that are linked to a client.
sv_active_cancelServer connections that are currently forwarding a cancel request.
sv_being_canceledServers 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_idleServer connections that are unused and immediately usable for client queries.
sv_usedServer connections that have been idle for more than
server_check_delay, so they needserver_check_queryto run on them before they can be used again.sv_testedServer connections that are currently running either
server_reset_queryorserver_check_query.sv_loginServer connections currently in the process of logging in.
maxwaitHow 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_sizesetting.maxwait_usMicrosecond part of the maximum waiting time.
pool_modeThe pooling mode in use.
SHOW PEER_POOLS
A new peer_pool entry is made for each configured peer.
databaseID of the configured peer entry.
cl_active_cancel_reqClient connections that have forwarded query cancellations to the server and are waiting for the server response.
cl_waiting_cancel_reqClient connections that have not forwarded query cancellations to the server yet.
sv_active_cancelServer connections that are currently forwarding a cancel request.
sv_loginServer connections currently in the process of logging in.
SHOW LISTS
Show following internal information, in columns (not rows):
databasesCount of databases.
usersCount of users.
poolsCount of pools.
free_clientsCount of free clients.
used_clientsCount of used clients.
login_clientsCount of clients in
loginstate.free_serversCount of free servers.
used_serversCount of used servers.
dns_namesCount of DNS names in the cache.
dns_zonesCount of DNS zones in the cache.
dns_queriesCount of in-flight DNS queries.
dns_pendingNot used.
SHOW USERS
nameThe user name.
pool_modeThe user's override
pool_mode, orNULLif the default will be used instead.
SHOW DATABASES
nameName of configured database entry.
hostHost pgbouncer connects to.
portPort pgbouncer connects to.
databaseActual database name pgbouncer connects to.
force_userWhen 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_sizeMaximum number of server connections.
min_pool_sizeMinimum number of server connections.
reserve_poolMaximum number of additional connections for this database.
pool_modeThe database's override pool_mode, or
NULLif the default will be used instead.max_connectionsMaximum number of allowed connections for this database, as set by
max_db_connections, either globally or per database.current_connectionsCurrent number of connections for this database.
paused1 if this database is currently paused, else 0.
disabled1 if this database is currently disabled, else 0.
SHOW PEERS
peer_idID of the configured peer entry.
hostHost pgbouncer connects to.
portPort pgbouncer connects to.
pool_sizeMaximum 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.
fdFile descriptor numeric value.
taskOne of
pooler,clientorserver.userUser of the connection using the FD.
databaseDatabase of the connection using the FD.
addrIP address of the connection using the FD,
unixif a Unix socket is used.portPort used by the connection using the FD.
cancelCancel key for this connection.
linkFile descriptor for corresponding server/client.
NULLif 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:
keyConfiguration variable name.
valueConfiguration value.
defaultConfiguration default value.
changeableEither
yesorno, shows if the variable can be changed while running. Ifno, the variable can be changed only at boot-time. UseSETto 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.
hostnameHost name.
ttlHow many seconds until next lookup.
addrsComma separated list of addresses.
SHOW DNS_ZONES
Show DNS zones in cache.
zonenameZone name.
serialCurrent serial.
countHost 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
SIGHUPReload config. Same as issuing the command
RELOADon the console.SIGINTSafe shutdown. Same as issuing
PAUSEandSHUTDOWNon the console.SIGTERMImmediate shutdown. Same as issuing
SHUTDOWNon the console.SIGUSR1Same as issuing
PAUSEon the console.SIGUSR2Same as issuing
RESUMEon the console.
Libevent Settings
From the libevent documentation:
It is possible to disable support for
epoll,kqueue,devpoll,poll, orselectby setting the environment variableEVENT_NOEPOLL,EVENT_NOKQUEUE,EVENT_NODEVPOLL,EVENT_NOPOLLorEVENT_NOSELECT, respectively.By setting the environment variable
EVENT_SHOW_METHOD,libeventdisplays 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
logfileSpecifies the log file. For daemonization (
-d), either this orsysloghas to be set. The log file is kept open, so after rotation,kill -HUPor on consoleRELOAD;should be done. On Windows, the service must be stopped and started.Note that setting
logfiledoes not by itself turn off logging to stderr. Use the command-line option-qor-dfor that.Default: not set
pidfileSpecifies the PID file. Without
pidfileset, daemonization (-d) is not allowed.Default: not set
listen_addrSpecifies 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_portWhich port to listen on. Applies to both TCP and Unix sockets.
Default: 6432
unix_socket_dirSpecifies 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_modeFile system mode for Unix socket. Ignored for sockets in the abstract namespace. Not supported on Windows.
Default: 0777
unix_socket_groupGroup name to use for Unix socket. Ignored for sockets in the abstract namespace. Not supported on Windows.
Default: not set
userIf 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_modeSpecifies when a server connection can be reused by other clients.
sessionServer is released back to pool after client disconnects. Default.
transactionServer is released back to pool after transaction finishes.
statementServer is released back to pool after query finishes. Transactions spanning multiple statements are disallowed in this mode.
max_client_connMaximum 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
ulimitin your favorite shell man page. Note:ulimitdoes not apply in a Windows environment.Default: 100
default_pool_sizeHow many server connections to allow per user/database pair. Can be overridden in the per-database configuration.
Default: 20
min_pool_sizeAdd 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_sizeHow many additional connections to allow to a pool (see
reserve_pool_timeout). The 0 value disables this parameter.Default: 0 (disabled)
reserve_pool_timeoutIf 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_connectionsDo 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_connectionsDo 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_robinBy 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_parametersBy default, pgbouncer tracks
client_encoding,datestyle,timezone,standard_conforming_stringsandapplication_nameparameters 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
postgresprotocol allows specifying parameter settings, both directly as a parameter in the startup packet, or inside theoptionsstartup packet. Parameters specified using both of these methods are supported bytrack_extra_parameters. However, it's not possible to includeoptionsitself intrack_extra_parameters, only the parameters contained inoptions.Default:
IntervalStyleignore_startup_parametersBy default, pgbouncer allows only parameters it can keep track of in startup packets:
client_encoding,datestyle,timezoneandstandard_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
postgresprotocol allows specifying parameter settings, both directly as a parameter in the startup packet, or inside theoptionsstartup packet. Parameters specified using both of these methods are supported byignore_startup_parameters. It's even possible to includeoptionsitself inignore_startup_parameters, which results in any unknown parameters contained insideoptionsto be ignored.Default: empty
peer_idThe peer ID used to identify this pgbouncer process in a group of pgbouncer processes that are peered together. The
peer_idvalue 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_idis 16383.Default: 0
disable_pqexecDisable 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_hostAdd 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_nameis later changed withSET, pgbouncer does not change it again.Default: 0
conffileShow location of current configuration file. Changing it will make pgbouncer use another configuration file for next
RELOAD/SIGHUP.Default: file from command line
service_nameUsed on win32 service registration.
Default:
pgbouncerjob_nameAlias for
service_name.stats_periodSets how often the averages shown in various
SHOWcommands 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_typeHow to authenticate users.
certThe client must connect over TLS connection with a valid client certificate. The user name is then taken from the
CommonNamefield from the certificate.md5Use MD5-based password check. This is the default authentication method.
auth_filemay contain both MD5-encrypted and plain-text passwords. Ifmd5is configured and a user has a SCRAM secret, then SCRAM authentication is used automatically instead.scram-sha-256Use password check with SCRAM-SHA-256.
auth_filehas 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.plainThe clear-text password is sent over the wire. Deprecated.
trustNo authentication is done. The user name must still exist in
auth_file.anyLike the
trustmethod, 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.hbaThe actual authentication type is loaded from
auth_hba_file. This allows different authentication methods for different access paths, for example: connections over Unix socket usepeerauthentication method, connections over TCP must use TLS.pamPluggable Authentication Modules (PAM) method is used to authenticate users,
auth_fileis ignored. This method is not compatible with databases using theauth_useroption. The service name reported to PAM ispgbouncer.pamis not supported in the HBA configuration file.
auth_hba_fileHBA configuration file to use when
auth_typeishba.Default: not set
auth_fileThe 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_fileorauth_userbe set; otherwise there would be no users defined.Default: not set
auth_userIf
auth_useris set, then any user not specified inauth_filewill be queried through theauth_queryquery frompg_shadowin the database, usingauth_user. The password ofauth_userwill be taken fromauth_file. (Ifauth_userdoes not require a password, then it does not need to be defined inauth_file.)Direct access to
pg_shadowrequires admin rights. It's preferable to use a non-superuser that calls aSECURITY DEFINERfunction instead.Default: not set
auth_queryQuery to load user's password from database.
Direct access to
pg_shadowrequires admin rights. It's preferable to use a non-superuser that calls aSECURITY DEFINERfunction 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=$1auth_dbnameDatabase 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
syslogToggles syslog on/off. On Windows, the event log is used instead.
Default: 0
syslog_identUnder what name to send logs to syslog.
Default:
pgbouncer(program name)syslog_facilityUnder what facility to send logs to syslog. Possibilities:
auth,authpriv,daemon,user,local0-7.Default:
daemonlog_connectionsLog successful logins.
Default: 1
log_disconnectionsLog disconnections with reasons.
Default: 1
log_pooler_errorsLog error messages the pooler sends to clients.
Default: 1
log_statsWrite aggregated statistics into the log, every
stats_period. This can be disabled if external monitoring tools are used to grab the same data fromSHOWcommands.Default: 1
verboseIncrease verbosity. Mirrors the
-vswitch on the command line. For example, using-v -von the command line is the same asverbose=2.Default: 0
Console Access Control
admin_usersComma-separated list of database users that are allowed to connect and run all commands on the console. Ignored when
auth_typeisany, in which case any user name is allowed in as admin.Default: empty
stats_usersComma-separated list of database users that are allowed to connect and run read-only queries on the console. That means all
SHOWcommands exceptSHOW FDS.Default: empty
Connection Sanity Checks, Timeouts
server_reset_queryQuery 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
ABORTorROLLBACK.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 ALLto just drop prepared statements, if the application does not break when some state is kept around.When transaction pooling is used, the
server_reset_queryis 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 ALLserver_reset_query_alwaysWhether
server_reset_queryshould be run in all pooling modes. When this setting is off (default), theserver_reset_querywill 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_delayHow long to keep released connections available for immediate re-use, without running
server_check_queryon it. If 0 then the query is always run.Default: 30.0
server_check_querySimple do-nothing query to check if the server connection is alive.
If an empty string, then sanity checking is disabled.
Default:
select 1server_fast_closeDisconnect a server in session pooling mode immediately or after the end of the current transaction if it is in
close_neededmode (set byRECONNECT,RELOADthat 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_lifetimeThe 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_timeoutIf 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_timeoutIf connection and login don't finish in this amount of time, the connection will be closed. [seconds]
Default: 15.0
server_login_retryIf 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
PAUSEcommand to avoid this.Default: 15.0
client_login_timeoutIf 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
SUSPENDand thus online restart. [seconds]Default: 60.0
autodb_idle_timeoutIf 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_ttlHow long DNS lookups can be cached. The actual DNS TTL is ignored. [seconds]
Default: 15.0
dns_nxdomain_ttlHow long DNS errors and
NXDOMAINDNS lookups can be cached. [seconds]Default: 15.0
dns_zone_check_periodPeriod 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_confThe location of a custom
resolv.conffile. 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_sslmodeTLS mode to use for connections from clients. TLS connections are disabled by default. When enabled,
client_tls_key_fileandclient_tls_cert_filemust be also configured to set up the key and certificate pgbouncer uses to accept client connections.disablePlain TCP. If client requests TLS, it's ignored. Default.
allowIf client requests TLS, it is used. If not, plain TCP is used. If the client presents a client certificate, it is not validated.
preferSame as
allow.requireThe client must use TLS. If not, the client connection is rejected. If the client presents a client certificate, it is not validated.
verify-caClient must use TLS with valid client certificate.
verify-fullSame as
verify-ca.
client_tls_key_filePrivate key for pgbouncer to accept client connections.
Default: not set
client_tls_cert_fileCertificate for private key. Clients can validate it.
Default: not set
client_tls_ca_fileRoot certificate file to validate client certificates.
Default: not set
client_tls_protocolsWhich 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:
secureclient_tls_ciphersAllowed 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:
fastclient_tls_ecdhcurveElliptic Curve name to use for ECDH key exchanges.
Allowed values:
none(DH is disabled),auto(256-bit ECDH), curve name.Default:
autoclient_tls_dheparamsDHE key exchange type.
Allowed values:
none(DH is disabled),auto(2048-bit DH),legacy(1024-bit DH).Default:
autoserver_tls_sslmodeTLS mode to use for connections to Postgres Pro servers. The default mode is
prefer.disablePlain TCP. TLS is not even requested from the server.
preferTLS connection is always requested first from Postgres Pro. If refused, the connection will be established over plain TCP. Server certificate is not validated. Default.
requireConnection must go over TLS. If server rejects it, plain TCP is not attempted. Server certificate is not validated.
verify-caConnection 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-fullConnection 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_fileRoot certificate file to validate Postgres Pro server certificates.
Default: not set
server_tls_key_filePrivate key for pgbouncer to authenticate against Postgres Pro server.
Default: not set
server_tls_cert_fileCertificate for private key. Postgres Pro server can validate it.
Default: not set
server_tls_protocolsWhich 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:
secureserver_tls_ciphersAllowed 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_timeoutQueries 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_timeoutMaximum 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_timeoutMaximum 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_timeoutClient 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_timeoutIf a client has been in the “idle in transaction” state longer, it will be disconnected. [seconds]
Default: 0.0 (disabled)
suspend_timeoutHow long to wait for buffer flush during
SUSPENDor reboot (-R). A connection is dropped if the flush does not succeed. [seconds]Default: 10
Low-Level Network Settings
pkt_bufInternal 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_sizeMaximum 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_backlogThe value of the
backlogargument 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_loopcntHow 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_bufamount of data. 0 means no limit.Default: 5
so_reuseportSpecifies whether to set the socket option
SO_REUSEPORTon 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_dirandpidfile, as well aslogfileif 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_idconfiguration option and the[peers]configuration section. There's also an example that uses peering andso_reuseportin the Examples section.Default: 0
tcp_defer_acceptSets the
TCP_DEFER_ACCEPTsocket option; seeman 7 tcpfor 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_bufferDefault: not set
tcp_keepaliveTurns 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_keepcntDefault: not set
tcp_keepidleDefault: not set
tcp_keepintvlDefault: not set
tcp_user_timeoutSets the
TCP_USER_TIMEOUTsocket 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.
dbnameDestination database name.
Default: same as client-side database name
hostHost name or IP address to connect to. Host names are resolved at connection time, the result is cached per
dns_max_ttlparameter. 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_robinfor 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
portDefault: 5432
userIf
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.
passwordIf no password is specified here, the password from the
auth_fileorauth_querywill be used.auth_userOverride of the global
auth_usersetting, if specified.pool_sizeSet the maximum size of pools for this database. If not set, the
default_pool_sizeis used.min_pool_sizeSet the minimum pool size for this database. If not set, the global
min_pool_sizeis used.reserve_poolSet additional connections for this database. If not set,
reserve_pool_sizeis used.connect_queryQuery 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_modeSet the pool mode specific to this database. If not set, the default
pool_modeis used.max_db_connectionsConfigure a database-wide maximum (i.e. all pools within the database will not have more than this many server connections).
client_encodingAsk specific
client_encodingfrom server.datestyleAsk specific
datestylefrom server.timezoneAsk specific
timezonefrom 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_modeSet the pool mode to be used for all connections from this user. If not set, the database or default
pool_modeis used.max_user_connectionsConfigure 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.
hostHost name or IP address to connect to. Host names are resolved at connection time, the result is cached per
dns_max_ttlparameter. 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
portDefault: 6432
pool_sizeIf not set, the
default_pool_sizeis 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 19.1.
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_typeare supported, pluspeerandreject, but exceptanyandpam, 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 $$
BEGIN
SELECT usename, passwd FROM pg_catalog.pg_shadow
WHERE usename = i_username INTO uname, phash;
REURN;
END;$$ LANUAGE plpgsql SECURITY DEFINER;
REVOKEALL ON FUNCTION pgbouncer.user_lookup(text) FROM public, pgbouncer;
GRANT XECUTE 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