pgbouncer配置

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 pooling: Most 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.

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

Create a users.txt file:
```
"someuser" "same_password_as_in_server"
```
Launch pgbouncer:
```
$ pgbouncer -d pgbouncer.ini
```
Have your application (or the psql client) connect to pgbouncer instead of directly to PostgreSQL server.
```
$ psql -p 6543 -U someuser template1
```

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

If you made changes to the pgbouncer.ini file, you can reload it with:

pgbouncer=# RELOAD;

参考：http://pgbouncer.projects.pgfoundry.org/doc/usage.html