.\" Automatically generated by Pandoc 2.9.2.1
.\"
.TH "PGBOUNCER" "1" "" "1.21.0" "Databases"
.hy
.SH NAME
.PP
pgbouncer - lightweight connection pooler for PostgreSQL
.SH SYNOPSIS
.IP
.nf
\f[C]
pgbouncer [-d][-R][-v][-u user] <pgbouncer.ini>
pgbouncer -V|-h
\f[R]
.fi
.PP
On Windows, the options are:
.IP
.nf
\f[C]
pgbouncer.exe [-v][-u user] <pgbouncer.ini>
pgbouncer.exe -V|-h
\f[R]
.fi
.PP
Additional options for setting up a Windows service:
.IP
.nf
\f[C]
pgbouncer.exe --regservice   <pgbouncer.ini>
pgbouncer.exe --unregservice <pgbouncer.ini>
\f[R]
.fi
.SH DESCRIPTION
.PP
\f[B]pgbouncer\f[R] is a PostgreSQL connection pooler.
Any target application can be connected to \f[B]pgbouncer\f[R] as if it
were a PostgreSQL server, and \f[B]pgbouncer\f[R] will create a
connection to the actual server, or it will reuse one of its existing
connections.
.PP
The aim of \f[B]pgbouncer\f[R] is to lower the performance impact of
opening new connections to PostgreSQL.
.PP
In order not to compromise transaction semantics for connection pooling,
\f[B]pgbouncer\f[R] supports several types of pooling when rotating
connections:
.TP
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.
.TP
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.
.TP
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.
.PP
The administration interface of \f[B]pgbouncer\f[R] consists of some new
\f[C]SHOW\f[R] commands available when connected to a special
\[lq]virtual\[rq] database \f[B]pgbouncer\f[R].
.SH QUICK-START
.PP
Basic setup and usage is as follows.
.IP "1." 3
Create a pgbouncer.ini file.
Details in \f[B]pgbouncer(5)\f[R].
Simple example:
.RS 4
.IP
.nf
\f[C]
 [databases]
 template1 = host=localhost port=5432 dbname=template1

 [pgbouncer]
 listen_port = 6432
 listen_addr = localhost
 auth_type = md5
 auth_file = userlist.txt
 logfile = pgbouncer.log
 pidfile = pgbouncer.pid
 admin_users = someuser
\f[R]
.fi
.RE
.IP "2." 3
Create a \f[C]userlist.txt\f[R] file that contains the users allowed in:
.RS 4
.IP
.nf
\f[C]
 \[dq]someuser\[dq] \[dq]same_password_as_in_server\[dq]
\f[R]
.fi
.RE
.IP "3." 3
Launch \f[B]pgbouncer\f[R]:
.RS 4
.IP
.nf
\f[C]
 $ pgbouncer -d pgbouncer.ini
\f[R]
.fi
.RE
.IP "4." 3
Have your application (or the \f[B]psql\f[R] client) connect to
\f[B]pgbouncer\f[R] instead of directly to the PostgreSQL server:
.RS 4
.IP
.nf
\f[C]
 $ psql -p 6432 -U someuser template1
\f[R]
.fi
.RE
.IP "5." 3
Manage \f[B]pgbouncer\f[R] by connecting to the special administration
database \f[B]pgbouncer\f[R] and issuing \f[C]SHOW HELP;\f[R] to begin:
.RS 4
.IP
.nf
\f[C]
 $ 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
   [...]
\f[R]
.fi
.RE
.IP "6." 3
If you made changes to the pgbouncer.ini file, you can reload it with:
.RS 4
.IP
.nf
\f[C]
 pgbouncer=# RELOAD;
\f[R]
.fi
.RE
.SH COMMAND LINE SWITCHES
.TP
\f[B]\f[CB]-d\f[B]\f[R], \f[B]\f[CB]--daemon\f[B]\f[R]
Run in the background.
Without it, the process will run in the foreground.
.RS
.PP
In daemon mode, setting \f[C]pidfile\f[R] as well as \f[C]logfile\f[R]
or \f[C]syslog\f[R] is required.
No log messages will be written to stderr after going into the
background.
.PP
Note: Does not work on Windows; \f[B]pgbouncer\f[R] need to run as
service there.
.RE
.TP
\f[B]\f[CB]-R\f[B]\f[R], \f[B]\f[CB]--reboot\f[B]\f[R]
\f[B]DEPRECATED: Instead of this option use a rolling restart with
multiple pgbouncer processes listening on the same port using
so_reuseport instead\f[R] 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
\f[C]unix_socket_dir\f[R] is not disabled in configuration.
Does not work on Windows.
Does not work with TLS connections, they are dropped.
.TP
\f[B]\f[CB]-u\f[B]\f[R] \f[I]USERNAME\f[R], \f[B]\f[CB]--user=\f[B]\f[R]\f[I]USERNAME\f[R]
Switch to the given user on startup.
.TP
\f[B]\f[CB]-v\f[B]\f[R], \f[B]\f[CB]--verbose\f[B]\f[R]
Increase verbosity.
Can be used multiple times.
.TP
\f[B]\f[CB]-q\f[B]\f[R], \f[B]\f[CB]--quiet\f[B]\f[R]
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.
.TP
\f[B]\f[CB]-V\f[B]\f[R], \f[B]\f[CB]--version\f[B]\f[R]
Show version.
.TP
\f[B]\f[CB]-h\f[B]\f[R], \f[B]\f[CB]--help\f[B]\f[R]
Show short help.
.TP
\f[B]\f[CB]--regservice\f[B]\f[R]
Win32: Register pgbouncer to run as Windows service.
The \f[B]service_name\f[R] configuration parameter value is used as the
name to register under.
.TP
\f[B]\f[CB]--unregservice\f[B]\f[R]
Win32: Unregister Windows service.
.SH ADMIN CONSOLE
.PP
The console is available by connecting as normal to the database
\f[B]pgbouncer\f[R]:
.IP
.nf
\f[C]
$ psql -p 6432 pgbouncer
\f[R]
.fi
.PP
Only users listed in the configuration parameters \f[B]admin_users\f[R]
or \f[B]stats_users\f[R] are allowed to log in to the console.
(Except when \f[C]auth_type=any\f[R], then any user is allowed in as a
stats_user.)
.PP
Additionally, the user name \f[B]pgbouncer\f[R] 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.
.PP
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.
.SS Show commands
.PP
The \f[B]SHOW\f[R] commands output information.
Each command is described below.
.SS SHOW STATS
.PP
Shows statistics.
In this and related commands, the total figures are since process start,
the averages are updated every \f[C]stats_period\f[R].
.TP
database
Statistics are presented per database.
.TP
total_xact_count
Total number of SQL transactions pooled by \f[B]pgbouncer\f[R].
.TP
total_query_count
Total number of SQL queries pooled by \f[B]pgbouncer\f[R].
.TP
total_received
Total volume in bytes of network traffic received by
\f[B]pgbouncer\f[R].
.TP
total_sent
Total volume in bytes of network traffic sent by \f[B]pgbouncer\f[R].
.TP
total_xact_time
Total number of microseconds spent by \f[B]pgbouncer\f[R] when connected
to PostgreSQL in a transaction, either idle in transaction or executing
queries.
.TP
total_query_time
Total number of microseconds spent by \f[B]pgbouncer\f[R] when actively
connected to PostgreSQL, executing queries.
.TP
total_wait_time
Time spent by clients waiting for a server, in microseconds.
Updated when a client connection is assigned a backend connection.
.TP
avg_xact_count
Average transactions per second in last stat period.
.TP
avg_query_count
Average queries per second in last stat period.
.TP
avg_recv
Average received (from clients) bytes per second.
.TP
avg_sent
Average sent (to clients) bytes per second.
.TP
avg_xact_time
Average transaction duration, in microseconds.
.TP
avg_query_time
Average query duration, in microseconds.
.TP
avg_wait_time
Average time spent by clients waiting for a server that were assigned a
backend connection within the current \f[C]stats_period\f[R], in
microseconds (averaged per second within that period).
.SS SHOW STATS_TOTALS
.PP
Subset of \f[B]SHOW STATS\f[R] showing the total values
(\f[B]total_\f[R]).
.SS SHOW STATS_AVERAGES
.PP
Subset of \f[B]SHOW STATS\f[R] showing the average values
(\f[B]avg_\f[R]).
.SS SHOW TOTALS
.PP
Like \f[B]SHOW STATS\f[R] but aggregated across all databases.
.SS SHOW SERVERS
.TP
type
S, for server.
.TP
user
User name \f[B]pgbouncer\f[R] uses to connect to server.
.TP
database
Database name.
.TP
state
State of the pgbouncer server connection, one of \f[B]active\f[R],
\f[B]idle\f[R], \f[B]used\f[R], \f[B]tested\f[R], \f[B]new\f[R],
\f[B]active_cancel\f[R], \f[B]being_canceled\f[R].
.TP
addr
IP address of PostgreSQL server.
.TP
port
Port of PostgreSQL server.
.TP
local_addr
Connection start address on local machine.
.TP
local_port
Connection start port on local machine.
.TP
connect_time
When the connection was made.
.TP
request_time
When last request was issued.
.TP
wait
Not used for server connections.
.TP
wait_us
Not used for server connections.
.TP
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 \f[B]RECONNECT\f[R] was issued.
.TP
ptr
Address of internal object for this connection.
Used as unique ID.
.TP
link
Address of client connection the server is paired with.
.TP
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\[cq]s extracted from cancel packet the server sent, which
should be the PID in case the server is PostgreSQL, but it\[cq]s a
random number in case the server it is another PgBouncer.
.TP
tls
A string with TLS connection information, or empty if not using TLS.
.TP
application_name
A string containing the \f[C]application_name\f[R] set on the linked
client connection, or empty if this is not set, or if there is no linked
connection.
.TP
prepared_statements
The amount of prepared statements that are prepared on the server.
This number is limited by the \f[C]max_prepared_statements\f[R] setting.
.SS SHOW CLIENTS
.TP
type
C, for client.
.TP
user
Client connected user.
.TP
database
Database name.
.TP
state
State of the client connection, one of \f[B]active\f[R],
\f[B]waiting\f[R], \f[B]active_cancel_req\f[R], or
\f[B]waiting_cancel_req\f[R].
.TP
addr
IP address of client.
.TP
port
Source port of client.
.TP
local_addr
Connection end address on local machine.
.TP
local_port
Connection end port on local machine.
.TP
connect_time
Timestamp of connect time.
.TP
request_time
Timestamp of latest client request.
.TP
wait
Current waiting time in seconds.
.TP
wait_us
Microsecond part of the current waiting time.
.TP
close_needed
not used for clients
.TP
ptr
Address of internal object for this connection.
Used as unique ID.
.TP
link
Address of server connection the client is paired with.
.TP
remote_pid
Process ID, in case client connects over Unix socket and OS supports
getting it.
.TP
tls
A string with TLS connection information, or empty if not using TLS.
.TP
application_name
A string containing the \f[C]application_name\f[R] set by the client for
this connection, or empty if this was not set.
.TP
prepared_statements
The amount of prepared statements that the client has prepared
.SS SHOW POOLS
.PP
A new pool entry is made for each couple of (database, user).
.TP
database
Database name.
.TP
user
User name.
.TP
cl_active
Client connections that are either linked to server connections or are
idle with no queries waiting to be processed.
.TP
cl_waiting
Client connections that have sent queries but have not yet got a server
connection.
.TP
cl_active_cancel_req
Client connections that have forwarded query cancellations to the server
and are waiting for the server response.
.TP
cl_waiting_cancel_req
Client connections that have not forwarded query cancellations to the
server yet.
.TP
sv_active
Server connections that are linked to a client.
.TP
sv_active_cancel
Server connections that are currently forwarding a cancel request.
.TP
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.
.TP
sv_idle
Server connections that are unused and immediately usable for client
queries.
.TP
sv_used
Server connections that have been idle for more than
\f[C]server_check_delay\f[R], so they need \f[C]server_check_query\f[R]
to run on them before they can be used again.
.TP
sv_tested
Server connections that are currently running either
\f[C]server_reset_query\f[R] or \f[C]server_check_query\f[R].
.TP
sv_login
Server connections currently in the process of logging in.
.TP
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
\f[B]pool_size\f[R] setting.
.TP
maxwait_us
Microsecond part of the maximum waiting time.
.TP
pool_mode
The pooling mode in use.
.SS SHOW PEER_POOLS
.PP
A new peer_pool entry is made for each configured peer.
.TP
database
ID of the configured peer entry.
.TP
cl_active_cancel_req
Client connections that have forwarded query cancellations to the server
and are waiting for the server response.
.TP
cl_waiting_cancel_req
Client connections that have not forwarded query cancellations to the
server yet.
.TP
sv_active_cancel
Server connections that are currently forwarding a cancel request.
.TP
sv_login
Server connections currently in the process of logging in.
.SS SHOW LISTS
.PP
Show following internal information, in columns (not rows):
.TP
databases
Count of databases.
.TP
users
Count of users.
.TP
pools
Count of pools.
.TP
free_clients
Count of free clients.
.TP
used_clients
Count of used clients.
.TP
login_clients
Count of clients in \f[B]login\f[R] state.
.TP
free_servers
Count of free servers.
.TP
used_servers
Count of used servers.
.TP
dns_names
Count of DNS names in the cache.
.TP
dns_zones
Count of DNS zones in the cache.
.TP
dns_queries
Count of in-flight DNS queries.
.TP
dns_pending
not used
.SS SHOW USERS
.TP
name
The user name
.TP
pool_mode
The user\[cq]s override pool_mode, or NULL if the default will be used
instead.
.SS SHOW DATABASES
.TP
name
Name of configured database entry.
.TP
host
Host pgbouncer connects to.
.TP
port
Port pgbouncer connects to.
.TP
database
Actual database name pgbouncer connects to.
.TP
force_user
When the user is part of the connection string, the connection between
pgbouncer and PostgreSQL is forced to the given user, whatever the
client user.
.TP
pool_size
Maximum number of server connections.
.TP
min_pool_size
Minimum number of server connections.
.TP
reserve_pool
Maximum number of additional connections for this database.
.TP
pool_mode
The database\[cq]s override pool_mode, or NULL if the default will be
used instead.
.TP
max_connections
Maximum number of allowed connections for this database, as set by
\f[B]max_db_connections\f[R], either globally or per database.
.TP
current_connections
Current number of connections for this database.
.TP
paused
1 if this database is currently paused, else 0.
.TP
disabled
1 if this database is currently disabled, else 0.
.SS SHOW PEERS
.TP
peer_id
ID of the configured peer entry.
.TP
host
Host pgbouncer connects to.
.TP
port
Port pgbouncer connects to.
.TP
pool_size
Maximum number of server connections that can be made to this peer
.SS SHOW FDS
.PP
Internal command - shows list of file descriptors in use with internal
state attached to them.
.PP
When the connected user has the user name \[lq]pgbouncer\[rq], connects
through the Unix socket and has same the 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.
.PP
This command also blocks the internal event loop, so it should not be
used while PgBouncer is in use.
.TP
fd
File descriptor numeric value.
.TP
task
One of \f[B]pooler\f[R], \f[B]client\f[R] or \f[B]server\f[R].
.TP
user
User of the connection using the FD.
.TP
database
Database of the connection using the FD.
.TP
addr
IP address of the connection using the FD, \f[B]unix\f[R] if a Unix
socket is used.
.TP
port
Port used by the connection using the FD.
.TP
cancel
Cancel key for this connection.
.TP
link
fd for corresponding server/client.
NULL if idle.
.SS SHOW SOCKETS, SHOW ACTIVE_SOCKETS
.PP
Shows low-level information about sockets or only active sockets.
This includes the information shown under \f[B]SHOW CLIENTS\f[R] and
\f[B]SHOW SERVERS\f[R] as well as other more low-level information.
.SS SHOW CONFIG
.PP
Show the current configuration settings, one per row, with the following
columns:
.TP
key
Configuration variable name
.TP
value
Configuration value
.TP
default
Configuration default value
.TP
changeable
Either \f[B]yes\f[R] or \f[B]no\f[R], shows if the variable can be
changed while running.
If \f[B]no\f[R], the variable can be changed only at boot time.
Use \f[B]SET\f[R] to change a variable at run time.
.SS SHOW MEM
.PP
Shows low-level information about the current sizes of various internal
memory allocations.
The information presented is subject to change.
.SS SHOW DNS_HOSTS
.PP
Show host names in DNS cache.
.TP
hostname
Host name.
.TP
ttl
How many seconds until next lookup.
.TP
addrs
Comma separated list of addresses.
.SS SHOW DNS_ZONES
.PP
Show DNS zones in cache.
.TP
zonename
Zone name.
.TP
serial
Current serial.
.TP
count
Host names belonging to this zone.
.SS SHOW VERSION
.PP
Show the PgBouncer version string.
.SS SHOW STATE
.PP
Show the PgBouncer state settings.
Current states are active, paused and suspended.
.SS Process controlling commands
.SS PAUSE [db]
.PP
PgBouncer tries to disconnect from all servers.
Disconnecting each server connection waits for that server connection to
be released according to the server pool\[cq]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.
.PP
If database name is given, only that database will be paused.
.PP
New client connections to a paused database will wait until
\f[B]RESUME\f[R] is called.
.SS DISABLE db
.PP
Reject all new client connections on the given database.
.SS ENABLE db
.PP
Allow new client connections after a previous \f[B]DISABLE\f[R] command.
.SS RECONNECT [db]
.PP
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.
.PP
This command is useful when the server connection setup has changed, for
example to perform a gradual switchover to a new server.
It is \f[I]not\f[R] necessary to run this command when the connection
string in pgbouncer.ini has been changed and reloaded (see
\f[B]RELOAD\f[R]) 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.
.PP
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, \f[B]PAUSE\f[R]
is recommended instead.
To close server connections without waiting (for example, in emergency
failover rather than gradual switchover scenarios), also consider
\f[B]KILL\f[R].
.SS KILL db
.PP
Immediately drop all client and server connections on given database.
.PP
New client connections to a killed database will wait until
\f[B]RESUME\f[R] is called.
.SS SUSPEND
.PP
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.
.PP
New client connections to a suspended database will wait until
\f[B]RESUME\f[R] is called.
.SS RESUME [db]
.PP
Resume work from previous \f[B]KILL\f[R], \f[B]PAUSE\f[R], or
\f[B]SUSPEND\f[R] command.
.SS SHUTDOWN
.PP
The PgBouncer process will exit.
.SS RELOAD
.PP
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 \f[C]auth_file\f[R] and \f[C]auth_hba_file\f[R].
.PP
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.
.SS WAIT_CLOSE [db]
.PP
Wait until all server connections, either of the specified database or
of all databases, have cleared the \[lq]close_needed\[rq] state (see
\f[B]SHOW SERVERS\f[R]).
This can be called after a \f[B]RECONNECT\f[R] or \f[B]RELOAD\f[R] to
wait until the respective configuration change has been fully activated,
for example in switchover scripts.
.SS Other commands
.SS SET key = arg
.PP
Changes a configuration setting (see also \f[B]SHOW CONFIG\f[R]).
For example:
.IP
.nf
\f[C]
SET log_connections = 1;
SET server_check_query = \[aq]select 2\[aq];
\f[R]
.fi
.PP
(Note that this command is run on the PgBouncer admin console and sets
PgBouncer settings.
A \f[B]SET\f[R] command run on another database will be passed to the
PostgreSQL backend like any other SQL command.)
.SS Signals
.TP
SIGHUP
Reload config.
Same as issuing the command \f[B]RELOAD\f[R] on the console.
.TP
SIGINT
Safe shutdown.
Same as issuing \f[B]PAUSE\f[R] and \f[B]SHUTDOWN\f[R] on the console.
.TP
SIGTERM
Immediate shutdown.
Same as issuing \f[B]SHUTDOWN\f[R] on the console.
.TP
SIGUSR1
Same as issuing \f[B]PAUSE\f[R] on the console.
.TP
SIGUSR2
Same as issuing \f[B]RESUME\f[R] on the console.
.SS Libevent settings
.PP
From the Libevent documentation:
.RS
.PP
It is possible to disable support for epoll, kqueue, devpoll, poll or
select by setting the environment variable EVENT_NOEPOLL,
EVENT_NOKQUEUE, EVENT_NODEVPOLL, EVENT_NOPOLL or EVENT_NOSELECT,
respectively.
.PP
By setting the environment variable EVENT_SHOW_METHOD, libevent displays
the kernel notification method that it uses.
.RE
.SH SEE ALSO
.PP
pgbouncer(5) - man page of configuration settings descriptions
.PP
<https://www.pgbouncer.org/>