使用pgpool-II进行postgresql的replication

最近一直研究postgresql,也想做一个像mysql一样的replication。 毕竟单台postgresql无论性能如何,总有撑不下去的时候。

网上查了下关于postgresql的一些资料,发现pg本身不带replication这个功能,master-slave也没有,但是一些第三方的软件可以支持这些,一开始发现slony似乎看着不错,但是配了一天发现这个东西配置实在是太复杂了,需要手动增加相关的库,以后增加新的也比较麻烦,而功能也比较单一。

后来问了下公司里来自yahoo的同事,发现yahoo是使用pgpool-II来实现的。找了下资料发现这个配置比较简单,基本是单个配置文件就可以搞定,而且有不同的conf.sample提供出来,有master-slave的config sample和replication的config sample.这样就节省了大量的时间了。

说下安装过程,还是比较简单。 安装时候需要指定一下postgresql的安装路径就可以了,其它没有特别的。


--with-pgsql=

--with-pgsql-includedir=

--with-pgsql-ibdir=

安装完成后在安装目录的etc下有几个实例文件。里面说明的也比较清楚。下面修改的一个是监听端口,由于我不想改程序,所以就让pgpoo-II直接监听5432端口,这个也是postgresql的默认端口。另外一个是relication_mode=yes,这个一定要这样选。load_balance_mode = true 这个就随意了,这个就是把select查询分配到2个不同的机器上。


#
# pgpool-II configuration file sample
# $Header: /cvsroot/pgpool/pgpool-II/pgpool.conf.sample,v 1.26 2009/02/15 05:26:28 t-ishii Exp $

# Host name or IP address to listen on: '*' for all, '' for no TCP/IP
# connections
listen_addresses = '192.168.100.1'

# Port number for pgpool
port = 5432

# Port number for pgpool communication manager
pcp_port = 9898

# Unix domain socket path.  (The Debian package defaults to
# /var/run/postgresql.)
socket_dir = '/tmp'

# Unix domain socket path for pgpool communication manager.
# (Debian package defaults to /var/run/postgresql)
pcp_socket_dir = '/tmp'

# Unix domain socket path for the backend. Debian package defaults to /var/run/postgresql!
backend_socket_dir = '/tmp'

# pgpool communication manager timeout. 0 means no timeout, but strongly not recommended!
pcp_timeout = 5

# number of pre-forked child process
num_init_children = 32

# Number of connection pools allowed for a child process
max_pool = 10

# If idle for this many seconds, child exits.  0 means no timeout.
child_life_time = 300

# If idle for this many seconds, connection to PostgreSQL closes.
# 0 means no timeout.
connection_life_time = 0

# If child_max_connections connections were received, child exits.
# 0 means no exit.
child_max_connections = 0

# If client_idle_limit is n (n > 0), the client is forced to be
# disconnected whenever after n seconds idle (even inside an explicit
# transactions!)
# 0 means no disconnect.
client_idle_limit = 0

# Maximum time in seconds to complete client authentication.
# 0 means no timeout.
authentication_timeout = 10

# Logging directory
logdir = '/tmp'

# pid file name
pid_file_name = '/tmp/pgpool.pid'

# Replication mode
replication_mode = true

# Load balancing mode, i.e., all SELECTs are load balanced.
# This is ignored if replication_mode is false.
load_balance_mode = true

# if there's a data mismatch between master and secondary
# start degeneration to stop replication mode
replication_stop_on_mismatch = false

# If true, replicate SELECT statement when load balancing is disabled.
# If false, it is only sent to the master node.
replicate_select = false

# Semicolon separated list of queries to be issued at the end of a session
reset_query_list = 'ABORT; RESET ALL; SET SESSION AUTHORIZATION DEFAULT'
# for 8.3 or newer PostgreSQL versions DISCARD ALL can be used as
# follows. However beware that DISCARD ALL holds exclusive lock on
# pg_listener so it will be a serious performance problem if there are
# lots of concurrent sessions.
# reset_query_list = 'ABORT; DISCARD ALL'

# If true print timestamp on each log line.
print_timestamp = true

# If true, operate in master/slave mode.
master_slave_mode = false

# If true, cache connection pool.
connection_cache = true

# Health check timeout.  0 means no timeout.
health_check_timeout = 20

# Health check period.  0 means no health check.
health_check_period = 0

# Health check user
health_check_user = 'nobody'

# Execute command by failover.
# special values:  %d = node id
#                  %h = host name
#                  %p = port number
#                  %D = database cluster path
#                  %m = new master node id
#                  %M = old master node id
#                  %% = '%' character
#
failover_command = ''

# Execute command by failback.
# special values:  %d = node id
#                  %h = host name
#                  %p = port number
#                  %D = database cluster path
#                  %m = new master node id
#                  %M = old master node id
#                  %% = '%' character
#
failback_command = ''

# If true, automatically locks a table with INSERT statements to keep
# SERIAL data consistency.  If the data does not have SERIAL data
# type, no lock will be issued. An /*INSERT LOCK*/ comment has the
# same effect.  A /NO INSERT LOCK*/ comment disables the effect.
insert_lock = true

# If true, ignore leading white spaces of each query while pgpool judges
# whether the query is a SELECT so that it can be load balanced.  This
# is useful for certain APIs such as DBI/DBD which is known to adding an
# extra leading white space.
ignore_leading_white_space = true

# If true, print all statements to the log.  Like the log_statement option
# to PostgreSQL, this allows for observing queries without engaging in full
# debugging.
log_statement = true

# If true, incoming connections will be printed to the log.
log_connections = true

# If true, hostname will be shown in ps status. Also shown in
# connection log if log_connections = true.
# Be warned that this feature will add overhead to look up hostname.
log_hostname = true

# if non 0, run in parallel query mode
parallel_mode = false

# if non 0, use query cache
enable_query_cache = false

#set pgpool2 hostname
pgpool2_hostname = ''

# system DB info
system_db_hostname = '192.168.100.1'
system_db_port = 5433
system_db_dbname = 'pgpool'
system_db_schema = 'pgpool_catalog'
system_db_user = 'pgpool'
system_db_password = ''

# backend_hostname, backend_port, backend_weight
# here are examples
backend_hostname0 = '192.168.100.1'
backend_port0 = 5433
backend_weight0 = 1
#backend_data_directory0 = '/data'
backend_hostname1 = '192.168.100.2'
backend_port1 = 5432
backend_weight1 = 1
#backend_data_directory1 = '/data1'

# - HBA -

# If true, use pool_hba.conf for client authentication. In pgpool-II
# 1.1, the default value is false. The default value will be true in
# 1.2.
enable_pool_hba = false

# - online recovery -
# online recovery user
recovery_user = 'nobody'

# online recovery password
recovery_password = ''

# execute a command in first stage.
recovery_1st_stage_command = ''

# execute a command in second stage.
recovery_2nd_stage_command = ''

# maximum time in seconds to wait for the recovering node's postmaster
# start-up. 0 means no wait.
# this is also used as a timer waiting for clients disconnected before
# starting 2nd stage
recovery_timeout = 90

# If client_idle_limit_in_recovery is n (n > 0), the client is forced
# to be disconnected whenever after n seconds idle (even inside an
# explicit transactions!)  0 means no disconnect. This parameter only
# takes effect in recovery 2nd stage.
client_idle_limit_in_recovery = 0

启动也简单


pgpool -n -d > /tmp/pgpool.log 2>&1

关闭也很容易


pgpool stop

关于 Timo
XNIX SA & MYSQL DBA

One Response to 使用pgpool-II进行postgresql的replication

  1. 王子说道:

    你是怎么配置他的并行查询的呢?

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