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PGBOUNCER(1) | PGBOUNCER(1) |
NAME¶
pgbouncer - Lightweight connection pooler for PostgreSQL.SYNOPSIS¶
pgbouncer [-d][-R][-v][-u user] <pgbouncer.ini> pgbouncer -V|-hOn Windows computers, the options are:
pgbouncer.exe [-v][-u user] <pgbouncer.ini> pgbouncer.exe -V|-hAdditional options for setting up a Windows service:
pgbouncer.exe -regservice <pgbouncer.ini> pgbouncer.exe -unregservice <pgbouncer.ini>
DESCRIPTION¶
pgbouncer is a PostgreSQL connection pooler. Any target application can be connected to pgbouncer as if it were a PostgreSQL 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 PostgreSQL. In order not to compromise transaction semantics for connection pooling, pgbouncer supports several types of pooling when rotating connections: Session poolingMost polite method. When 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 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 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 as following. 1.Create a pgbouncer.ini file. Details in pgbouncer(5).
Simple example:
[databases] template1 = host=127.0.0.1 port=5432 dbname=template1
[pgbouncer] listen_port = 6543 listen_addr = 127.0.0.1 auth_type = md5 auth_file = users.txt logfile = pgbouncer.log pidfile = pgbouncer.pid admin_users = someuser
2.Create a users.txt file:
"someuser" "same_password_as_in_server"
3.Launch pgbouncer:
$ pgbouncer -d pgbouncer.ini
4.Have your application (or the psql client) connect to
pgbouncer instead of directly to PostgreSQL server.
$ psql -p 6543 -U someuser template1
5.Manage pgbouncer by connecting to the special
administration database pgbouncer and issuing show help; to begin:
$ psql -p 6543 -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
6.If you made changes to the pgbouncer.ini file, you can
reload it with:
pgbouncer=# RELOAD;
COMMAND LINE SWITCHES¶
-dRun in background. Without it the process will run in
foreground. Note: Does not work on Windows, pgbouncer need to run as service
there.
-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 unix_socket_dir is not disabled in config. Does not work
on Windows machines.
-u user
Switch to the given user on startup.
-v
Increase verbosity. Can be used multiple times.
-q
Be quiet - do not log to stdout. Note this does not
affect logging verbosity, only that stdout is not to be used. For use in
init.d scripts.
-V
Show version.
-h
Show short help.
-regservice
Win32: Register pgbouncer to run as Windows service. The
service_name config parameter value is used as 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 6543 pgbouncer
SHOW COMMANDS¶
The SHOW commands output information. Each command is described below.
Shows statistics.
database
Statistics are presented per database.
total_requests
Total number of SQL requests 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_query_time
Total number of microseconds spent by pgbouncer when
actively connected to PostgreSQL.
avg_req
Average requests 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_query
Average query duration in microseconds.
type
S, for server.
user
Username pgbouncer uses to connect to server.
database
Database name.
state
State of the pgbouncer server connection, one of active,
used or idle.
addr
IP address of PostgreSQL server.
port
Port of PostgreSQL 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.
ptr
Address of internal object for this connection. Used as
unique ID.
link
Address of client connection the server is paired
with.
type
C, for client.
user
Client connected user.
database
Database name.
state
State of the client connection, one of active, used,
waiting or idle.
addr
IP address of client.
port
Port client is connected to.
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.
ptr
Address of internal object for this connection. Used as
unique ID.
link
Address of server connection the client is paired
with.
A new pool entry is made for each couple of (database, user).
database
Database name.
user
User name.
cl_active
Client connections that are linked to server connection
and can process queries.
cl_waiting
Client connections have sent queries but have not yet got
a server connection.
sv_active
Server connections that linked to client.
sv_idle
Server connections that unused and immediately usable for
client queries.
sv_used
Server connections that have been idle more than
server_check_delay, so they needs server_check_query to run on it before it
can be used.
sv_tested
Server connections that are currently running either
server_reset_query or server_check_query.
sv_login
Server connections currently in logging in process.
maxwait
How long the first (oldest) client in queue has waited,
in seconds. If this starts increasing, then the current pool of servers does
not handle requests quick enough. Reason may be either overloaded server or
just too small of a pool_size setting.
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.
Shows one line per user, under the name column name.
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 user is part of the connection string, the
connection between pgbouncer and PostgreSQL is forced to the given user,
whatever the client user.
pool_size
Maximum number of server connections.
Shows list of fds in use. When the connected user has username
"pgbouncer", connects through Unix socket and has same UID as
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 machines.
fd
File descriptor numeric value.
task
One of pooler, client or server.
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
fd for corresponding server/client. NULL if idle.
Show the current configuration settings, one per row, with following columns:
key
Configuration variable name
value
Configuration value
changeable
Either yes or no, shows if the variable can be changed
while running. If no, the variable can be changed only boot-time.
Show hostnames in DNS cache.
hostname
Host name.
ttl
How meny seconds until next lookup.
addrs
Comma separated list of addresses.
Show DNS zones in cache.
zonename
Zone name.
serial
Current serial.
count
Hostnames belonging to this zone.
PROCESS CONTROLLING COMMANDS¶
PAUSE [db];
PgBouncer tries to disconnect from all servers, first waiting for all queries to
complete. The command will not return before all queries are finished. To be
used at the time of database restart.
If database name is given, only that database will be paused.
Immediately drop all client and server connections on given database.
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.
Resume work from previous PAUSE or SUSPEND command.
The PgBouncer process will exit.
The PgBouncer process will reload its configuration file and update changeable
settings.
SIGNALS¶
SIGHUPReload config. Same as issuing command RELOAD; on
console.
SIGINT
Safe shutdown. Same as issuing PAUSE; and SHUTDOWN; on
console.
SIGTERM
Immediate shutdown. Same as issuing SHUTDOWN; on
console.
LIBEVENT SETTINGS¶
From libevent docs: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.
By setting the environment variable EVENT_SHOW_METHOD, libevent displays the kernel notification method that it uses.
SEE ALSO¶
pgbouncer(5) - manpage of configuration settings descriptions. http://wiki.postgresql.org/wiki/PgBouncer05/23/2015 |