PostgreSQL的HA解决方案-2负载均衡(load balance)

 一.部署说明

1.1 实施环境

本文档实验环境如下:

PGSQL主机: 192.168.1.45

PGSQL备机: 192.168.1.50

 

软件和系统版本

Pgsql 版本: pgsql 9.2.4

Linux 版本: Redhat 5.8

pgpool版本:pgpool-II version 3.3.4 (tokakiboshi)

 

1.2 文档说明  

  在postgresql 的stream replication配置一文我们实现了postgresql的stream replication,实现了postgresql的热备。而实际生产中集群的目的之一就是负载均衡。那我们系统为例,刚开始java程序需要修改数据源,将查询的压力分担给从机,对数据的修改设置为主机。但是这种方式不灵活,负载不能均衡,并且比较麻烦。所以如果此时有一个路由控制器多好,可以根据请求将请求分发给不同的数据库。刚好,pgpoool就是这么一个中间件,负责与数据库集群交互,对外提供统一的访问接口,使得程序对数据库的访问变得简单,提高整个系统的性能。本文主要配置pgpool的负载均衡,是在上篇博文:PostgreSQL的HA解决方案-1主从和备份(master/slave and backup) 的基础之上配置的。

  为了试验减少不必要的麻烦,本系列试验中,各个主机之间的通信,都是设置为无密码访问,且关闭主从的防火墙,但对于实际生产,需要根据实际需要,配置密码,增强集群的安全性。

二.配置步骤

  1.1 源码安装pgpool。参考中文手册:http://pgpool.projects.pgfoundry.org/pgpool-II/doc/pgpool-zh_cn.html#install

  1.2 安装pgpool中提供的工具。安装 pgpool_regclass。注意 pgpool_regclass是在你解压pgpool后的目录中的sql目录下,而不是你的安装目录。

    pgpool_regclass主要作用是,方便在数据库查询中,查询关于pgpool的的配置参数,监控信息等,请仔细阅读中文手册。应在在每台通过 pgpool-II 访问的数据库中执行 pgpool-regclass.sql。你不需要在你执行“psql -f pgpool-regclass.sql template1”后建立的数据库中这么做,因为这个模板数据库将被克隆成新建的数据库。

cd pgpool-II-x.x.x/sql/pgpool-regclass
make
make install
psql -f pgpool-regclass.sql template1

    安装之后,再在/usr/local/pgsql/share/extension/目录下多出如下文件:

-rw-r--r-- 1 root root 152 Sep 10 09:29 pgpool_regclass.control
-rw-r--r-- 1 root root 283 Sep 10 09:29 pgpool_regclass--1.0.sql
-rw-r--r-- 1 root root 142 Sep 10 09:29 pgpool-regclass.sql

  1.3 配置pgpool的配置文件。

   主要配置:

listen_addresses="*"
port=5433
backend_hostname0="localhost"
backend_port0="5432"
backend_weight0=1
backend_hostname1="192.168.57.175"
backend_port1="5432"
backend_weight1=1
replication_mode=off
load_balance_mode=on
master_slave_mode=on
master_save_sub_mode="stream"
parallel_mode=off

详细配置:

# ----------------------------
# pgPool-II configuration file
# ----------------------------
#
# This file consists of lines of the form:
#
#   name = value
#
# Whitespace may be used.  Comments are introduced with "#" anywhere on a line.
# The complete list of parameter names and allowed values can be found in the
# pgPool-II documentation.
#
# This file is read on server startup and when the server receives a SIGHUP
# signal.  If you edit the file on a running system, you have to SIGHUP the
# server for the changes to take effect, or use "pgpool reload".  Some
# parameters, which are marked below, require a server shutdown and restart to
# take effect.
#


#------------------------------------------------------------------------------
# CONNECTIONS
#------------------------------------------------------------------------------

# - pgpool Connection Settings -

#listen_addresses = 'localhost'
listen_addresses = '*'
                                   # Host name or IP address to listen on:
                                   # '*' for all, '' for no TCP/IP connections
                                   # (change requires restart)
port = 9999
                                   # Port number
                                   # (change requires restart)
socket_dir = '/tmp'
                                   # Unix domain socket path
                                   # The Debian package defaults to
                                   # /var/run/postgresql
                                   # (change requires restart)


# - pgpool Communication Manager Connection Settings -

pcp_port = 9898
                                   # Port number for pcp
                                   # (change requires restart)
pcp_socket_dir = '/tmp'
                                   # Unix domain socket path for pcp
                                   # The Debian package defaults to
                                   # /var/run/postgresql
                                   # (change requires restart)

# - Backend Connection Settings -

#backend_hostname0 = 'host1'
backend_hostname0 = '192.168.1.45'
                                   # Host name or IP address to connect to for backend 0
backend_port0 = 5432
                                   # Port number for backend 0
backend_weight0 = 1
                                   # Weight for backend 0 (only in load balancing mode)
#backend_data_directory0 = '/data'
                                   # Data directory for backend 0
backend_flag0 = 'ALLOW_TO_FAILOVER'
                                   # Controls various backend behavior
                                   # ALLOW_TO_FAILOVER or DISALLOW_TO_FAILOVER
backend_hostname1 = '192.168.1.50'
backend_port1 = 5432
backend_weight1 = 1
#backend_data_directory1 = '/data1'
backend_flag1 = 'ALLOW_TO_FAILOVER'

# - Authentication -

enable_pool_hba = on
                                   # Use pool_hba.conf for client authentication
pool_passwd = 'pool_passwd'
                                   # File name of pool_passwd for md5 authentication.
                                   # "" disables pool_passwd.
                                   # (change requires restart)
authentication_timeout = 60
                                   # Delay in seconds to complete client authentication
                                   # 0 means no timeout.

# - SSL Connections -

ssl = off
                                   # Enable SSL support
                                   # (change requires restart)
#ssl_key = './server.key'
                                   # Path to the SSL private key file
                                   # (change requires restart)
#ssl_cert = './server.cert'
                                   # Path to the SSL public certificate file
                                   # (change requires restart)
#ssl_ca_cert = ''
                                   # Path to a single PEM format file
                                   # containing CA root certificate(s)
                                   # (change requires restart)
#ssl_ca_cert_dir = ''
                                   # Directory containing CA root certificate(s)
                                   # (change requires restart)


#------------------------------------------------------------------------------
# POOLS
#------------------------------------------------------------------------------

# - Pool size -

num_init_children = 10
                                   # Number of pools
                                   # (change requires restart)
max_pool = 2
                                   # Number of connections per pool
                                   # (change requires restart)

# - Life time -

child_life_time = 300
                                   # Pool exits after being idle for this many seconds
child_max_connections = 0
                                   # Pool exits after receiving that many connections
                                   # 0 means no exit
connection_life_time = 0
                                   # Connection to backend closes after being idle for this many seconds
                                   # 0 means no close
client_idle_limit = 0
                                   # Client is disconnected after being idle for that many seconds
                                   # (even inside an explicit transactions!)
                                   # 0 means no disconnection


#------------------------------------------------------------------------------
# LOGS
#------------------------------------------------------------------------------

# - Where to log -

log_destination = 'stderr'
                                   # Where to log
                                   # Valid values are combinations of stderr,
                                   # and syslog. Default to stderr.

# - What to log -

print_timestamp = on
                                   # Print timestamp on each line
                                   # (change requires restart)

log_connections = on
                                   # Log connections
log_hostname = on
                                   # Hostname will be shown in ps status
                                   # and in logs if connections are logged
log_statement = on
                                   # Log all statements
log_per_node_statement = off
                                   # Log all statements
                                   # with node and backend informations
log_standby_delay = 'none'
                                   # Log standby delay
                                   # Valid values are combinations of always,
                                   # if_over_threshold, none

# - Syslog specific -

syslog_facility = 'LOCAL0'
                                   # Syslog local facility. Default to LOCAL0
syslog_ident = 'pgpool'
                                   # Syslog program identification string
                                   # Default to 'pgpool'

# - Debug -

debug_level = 0
                                   # Debug message verbosity level
                                   # 0 means no message, 1 or more mean verbose


#------------------------------------------------------------------------------
# FILE LOCATIONS
#------------------------------------------------------------------------------

pid_file_name = '/var/run/pgpool/pgpool.pid'
                                   # PID file name
                                   # (change requires restart)
logdir = '/tmp'
                                   # Directory of pgPool status file
                                   # (change requires restart)


#------------------------------------------------------------------------------
# CONNECTION POOLING
#------------------------------------------------------------------------------

connection_cache = on
                                   # Activate connection pools
                                   # (change requires restart)

                                   # Semicolon separated list of queries
                                   # to be issued at the end of a session
                                   # The default is for 8.3 and later
reset_query_list = 'ABORT; DISCARD ALL'
                                   # The following one is for 8.2 and before
#reset_query_list = 'ABORT; RESET ALL; SET SESSION AUTHORIZATION DEFAULT'


#------------------------------------------------------------------------------
# REPLICATION MODE
#------------------------------------------------------------------------------

replication_mode = off
                                   # Activate replication mode
                                   # (change requires restart)
replicate_select = off
                                   # Replicate SELECT statements
                                   # when in replication or parallel mode
                                   # replicate_select is higher priority than
                                   # load_balance_mode.

insert_lock = on
                                   # Automatically locks a dummy row or a table
                                   # with INSERT statements to keep SERIAL data
                                   # consistency
                                   # Without SERIAL, no lock will be issued
lobj_lock_table = ''
                                   # When rewriting lo_creat command in
                                   # replication mode, specify table name to
                                   # lock

# - Degenerate handling -

replication_stop_on_mismatch = off
                                   # On disagreement with the packet kind
                                   # sent from backend, degenerate the node
                                   # which is most likely "minority"
                                   # If off, just force to exit this session

failover_if_affected_tuples_mismatch = off
                                   # On disagreement with the number of affected
                                   # tuples in UPDATE/DELETE queries, then
                                   # degenerate the node which is most likely
                                   # "minority".
                                   # If off, just abort the transaction to
                                   # keep the consistency


#------------------------------------------------------------------------------
# LOAD BALANCING MODE
#------------------------------------------------------------------------------

load_balance_mode = on
                                   # Activate load balancing mode
                                   # (change requires restart)
ignore_leading_white_space = on
                                   # Ignore leading white spaces of each query
white_function_list = ''
                                   # Comma separated list of function names
                                   # that don't write to database
                                   # Regexp are accepted
black_function_list = 'nextval,setval'
                                   # Comma separated list of function names
                                   # that write to database
                                   # Regexp are accepted


#------------------------------------------------------------------------------
# MASTER/SLAVE MODE
#------------------------------------------------------------------------------

master_slave_mode = on
                                   # Activate master/slave mode
                                   # (change requires restart)
master_slave_sub_mode = 'stream'
                                   # Master/slave sub mode
                                   # Valid values are combinations slony or
                                   # stream. Default is slony.
                                   # (change requires restart)

# - Streaming -

#sr_check_period = 0
sr_check_period = 10
                                   # Streaming replication check period
                                   # Disabled (0) by default
sr_check_user = 'postgres'
                                   # Streaming replication check user
                                   # This is necessary even if you disable
                                   # streaming replication delay check with
                                   # sr_check_period = 0
sr_check_password = 'postgres123'
                                   # Password for streaming replication check user
delay_threshold = 0
                                   # Threshold before not dispatching query to standby node
                                   # Unit is in bytes
                                   # Disabled (0) by default

# - Special commands -

follow_master_command = ''
                                   # Executes this command after master failover
                                   # Special values:
                                   #   %d = node id
                                   #   %h = host name
                                   #   %p = port number
                                   #   %D = database cluster path
                                   #   %m = new master node id
                                   #   %H = hostname of the new master node
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %% = '%' character


#------------------------------------------------------------------------------
# PARALLEL MODE
#------------------------------------------------------------------------------

parallel_mode = off
                                   # Activates parallel query mode
                                   # (change requires restart)
pgpool2_hostname = ''
                                   # Set pgpool2 hostname
                                   # (change requires restart)

# - System DB info -

system_db_hostname  = 'localhost'
                                   # (change requires restart)
system_db_port = 5432
                                   # (change requires restart)
system_db_dbname = 'pgpool'
                                   # (change requires restart)
system_db_schema = 'pgpool_catalog'
                                   # (change requires restart)
system_db_user = 'pgpool'
                                   # (change requires restart)
system_db_password = ''
                                   # (change requires restart)


#------------------------------------------------------------------------------
# HEALTH CHECK
#------------------------------------------------------------------------------

#health_check_period = 0
health_check_period = 30
                                   # Health check period
                                   # Disabled (0) by default
health_check_timeout = 20
                                   # Health check timeout
                                   # 0 means no timeout
health_check_user = 'postgres'
                                   # Health check user
health_check_password = 'postgres123'
                                   # Password for health check user
health_check_max_retries = 0
                                   # Maximum number of times to retry a failed health check before giving up.
health_check_retry_delay = 1
                                   # Amount of time to wait (in seconds) between retries.


#------------------------------------------------------------------------------
# FAILOVER AND FAILBACK
#------------------------------------------------------------------------------

failover_command = '/home/postgres/scripts/failover_stream.sh %d %H /usr/local/pgsql/data/postgresql.trigger.5432'
                                   # Executes this command at failover
                                   # Special values:
                                   #   %d = node id
                                   #   %h = host name
                                   #   %p = port number
                                   #   %D = database cluster path
                                   #   %m = new master node id
                                   #   %H = hostname of the new master node
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %% = '%' character
failback_command = ''
                                   # Executes this command at failback.
                                   # Special values:
                                   #   %d = node id
                                   #   %h = host name
                                   #   %p = port number
                                   #   %D = database cluster path
                                   #   %m = new master node id
                                   #   %H = hostname of the new master node
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %% = '%' character

fail_over_on_backend_error = on
                                   # Initiates failover when reading/writing to the
                                   # backend communication socket fails
                                   # If set to off, pgpool will report an
                                   # error and disconnect the session.

search_primary_node_timeout = 10
                                   # Timeout in seconds to search for the
                                   # primary node when a failover occurs.
                                   # 0 means no timeout, keep searching
                                   # for a primary node forever.

#------------------------------------------------------------------------------
# ONLINE RECOVERY
#------------------------------------------------------------------------------

recovery_user = 'postgres'
                                   # Online recovery user
recovery_password = 'postgres123'
                                   # Online recovery password
recovery_1st_stage_command = ''
                                   # Executes a command in first stage
recovery_2nd_stage_command = ''
                                   # Executes a command in second stage
recovery_timeout = 90
                                   # Timeout in seconds to wait for the
                                   # recovering node's postmaster to start up
                                   # 0 means no wait
client_idle_limit_in_recovery = 0
                                   # Client is disconnected after being idle
                                   # for that many seconds in the second stage
                                   # of online recovery
                                   # 0 means no disconnection
                                   # -1 means immediate disconnection


#------------------------------------------------------------------------------
# WATCHDOG
#------------------------------------------------------------------------------

# - Enabling -

use_watchdog = off
                                    # Activates watchdog
                                    # (change requires restart)

# -Connection to up stream servers -

trusted_servers = ''
                                    # trusted server list which are used
                                    # to confirm network connection
                                    # (hostA,hostB,hostC,...)
                                    # (change requires restart)
ping_path = '/bin'
                                    # ping command path
                                    # (change requires restart)

# - Watchdog communication Settings -

wd_hostname = ''
                                    # Host name or IP address of this watchdog
                                    # (change requires restart)
wd_port = 9000
                                    # port number for watchdog service
                                    # (change requires restart)
wd_authkey = ''
                                    # Authentication key for watchdog communication
                                    # (change requires restart)

# - Virtual IP control Setting -

delegate_IP = ''
                                    # delegate IP address
                                    # If this is empty, virtual IP never bring up. 
                                    # (change requires restart)
ifconfig_path = '/sbin'
                                    # ifconfig command path
                                    # (change requires restart)
if_up_cmd = 'ifconfig eth0:0 inet $_IP_$ netmask 255.255.255.0'
                                    # startup delegate IP command
                                    # (change requires restart)
if_down_cmd = 'ifconfig eth0:0 down'
                                    # shutdown delegate IP command
                                    # (change requires restart)

arping_path = '/usr/sbin'           # arping command path
                                    # (change requires restart)

arping_cmd = 'arping -U $_IP_$ -w 1'
                                    # arping command
                                    # (change requires restart)

# - Behaivor on escalation Setting -

clear_memqcache_on_escalation = on
                                    # Clear all the query cache on shared memory
                                    # when standby pgpool escalate to active pgpool
                                    # (= virtual IP holder).
                                    # This should be off if client connects to pgpool
                                    # not using virtual IP.
                                    # (change requires restart)
wd_escalation_command = ''
                                    # Executes this command at escalation on new active pgpool.
                                    # (change requires restart)

# - Lifecheck Setting - 

# -- common --

wd_lifecheck_method = 'heartbeat'
                                    # Method of watchdog lifecheck ('heartbeat' or 'query')
                                    # (change requires restart)
wd_interval = 10
                                    # lifecheck interval (sec) > 0
                                    # (change requires restart)

# -- heartbeat mode --

wd_heartbeat_port = 9694
                                    # Port number for receiving heartbeat signal
                                    # (change requires restart)
wd_heartbeat_keepalive = 2
                                    # Interval time of sending heartbeat signal (sec)
                                    # (change requires restart)
wd_heartbeat_deadtime = 30
                                    # Deadtime interval for heartbeat signal (sec)
                                    # (change requires restart)
heartbeat_destination0 = 'db2'
                                    # Host name or IP address of destination 0
                                    # for sending heartbeat signal.
                                    # (change requires restart)
heartbeat_destination_port0 = 9694 
                                    # Port number of destination 0 for sending
                                    # heartbeat signal. Usually this is the
                                    # same as wd_heartbeat_port.
                                    # (change requires restart)
heartbeat_device0 = ''
                                    # Name of NIC device (such like 'eth0')
                                    # used for sending/receiving heartbeat
                                    # signal to/from destination 0.
                                    # This works only when this is not empty
                                    # and pgpool has root privilege.
                                    # (change requires restart)

#heartbeat_destination1 = 'host0_ip2'
#heartbeat_destination_port1 = 9694
#heartbeat_device1 = ''

# -- query mode --

wd_life_point = 3
                                    # lifecheck retry times
                                    # (change requires restart)
wd_lifecheck_query = 'SELECT 1'
                                    # lifecheck query to pgpool from watchdog
                                    # (change requires restart)
wd_lifecheck_dbname = 'template1'
                                    # Database name connected for lifecheck
                                    # (change requires restart)
wd_lifecheck_user = 'nobody'
                                    # watchdog user monitoring pgpools in lifecheck
                                    # (change requires restart)
wd_lifecheck_password = ''
                                    # Password for watchdog user in lifecheck
                                    # (change requires restart)

# - Other pgpool Connection Settings -

#other_pgpool_hostname0 = 'host0'
                                    # Host name or IP address to connect to for other pgpool 0
                                    # (change requires restart)
#other_pgpool_port0 = 5432
                                    # Port number for othet pgpool 0
                                    # (change requires restart)
#other_wd_port0 = 9000
                                    # Port number for othet watchdog 0
                                    # (change requires restart)
#other_pgpool_hostname1 = 'host1'
#other_pgpool_port1 = 5432
#other_wd_port1 = 9000


#------------------------------------------------------------------------------
# OTHERS
#------------------------------------------------------------------------------
relcache_expire = 0
                                   # Life time of relation cache in seconds.
                                   # 0 means no cache expiration(the default).
                                   # The relation cache is used for cache the
                                   # query result against PostgreSQL system
                                   # catalog to obtain various information
                                   # including table structures or if it's a
                                   # temporary table or not. The cache is
                                   # maintained in a pgpool child local memory
                                   # and being kept as long as it survives.
                                   # If someone modify the table by using
                                   # ALTER TABLE or some such, the relcache is
                                   # not consistent anymore.
                                   # For this purpose, cache_expiration
                                   # controls the life time of the cache.

relcache_size = 256
                                   # Number of relation cache
                                   # entry. If you see frequently:
                                   # "pool_search_relcache: cache replacement happend"
                                   # in the pgpool log, you might want to increate this number.

check_temp_table = on
                                   # If on, enable temporary table check in SELECT statements.
                                   # This initiates queries against system catalog of primary/master
                                   # thus increases load of master.
                                   # If you are absolutely sure that your system never uses temporary tables
                                   # and you want to save access to primary/master, you could turn this off.
                                   # Default is on.


#------------------------------------------------------------------------------
# ON MEMORY QUERY MEMORY CACHE
#------------------------------------------------------------------------------
memory_cache_enabled = off
                                   # If on, use the memory cache functionality, off by default
memqcache_method = 'shmem'
                                   # Cache storage method. either 'shmem'(shared memory) or
                                   # 'memcached'. 'shmem' by default
                                   # (change requires restart)
memqcache_memcached_host = 'localhost'
                                   # Memcached host name or IP address. Mandatory if
                                   # memqcache_method = 'memcached'.
                                   # Defaults to localhost.
                                   # (change requires restart)
memqcache_memcached_port = 11211
                                   # Memcached port number. Mondatory if memqcache_method = 'memcached'.
                                   # Defaults to 11211.
                                   # (change requires restart)
memqcache_total_size = 67108864
                                   # Total memory size in bytes for storing memory cache.
                                   # Mandatory if memqcache_method = 'shmem'.
                                   # Defaults to 64MB.
                                   # (change requires restart)
memqcache_max_num_cache = 1000000
                                   # Total number of cache entries. Mandatory
                                   # if memqcache_method = 'shmem'.
                                   # Each cache entry consumes 48 bytes on shared memory.
                                   # Defaults to 1,000,000(45.8MB).
                                   # (change requires restart)
memqcache_expire = 0
                                   # Memory cache entry life time specified in seconds.
                                   # 0 means infinite life time. 0 by default.
                                   # (change requires restart)
memqcache_auto_cache_invalidation = on
                                   # If on, invalidation of query cache is triggered by corresponding
                                   # DDL/DML/DCL(and memqcache_expire).  If off, it is only triggered
                                   # by memqcache_expire.  on by default.
                                   # (change requires restart)
memqcache_maxcache = 409600
                                   # Maximum SELECT result size in bytes.
                                   # Must be smaller than memqcache_cache_block_size. Defaults to 400KB.
                                   # (change requires restart)
memqcache_cache_block_size = 1048576
                                   # Cache block size in bytes. Mandatory if memqcache_method = 'shmem'.
                                   # Defaults to 1MB.
                                   # (change requires restart)
memqcache_oiddir = '/var/log/pgpool/oiddir'
                                      # Temporary work directory to record table oids
                                   # (change requires restart)
white_memqcache_table_list = ''
                                   # Comma separated list of table names to memcache
                                   # that don't write to database
                                   # Regexp are accepted
black_memqcache_table_list = ''
                                   # Comma separated list of table names not to memcache
                                   # that don't write to database
                                   # Regexp are accepted
View Code

   1.4 启动pgpool:pgpool -dn 以非守护进程,调试模式运行pgpool,因为如果默认是守护进程,待会想停止就麻烦了。其他参数--help.

注意观察调试信息。如果有错误,请重新查看配置文件。如果没有法相错误,使用命令:psql -p 9999 ,通过pgpool进入数据库。如果可以进入就说明pgpool监听的9999正常,且成功连接数据库。

   此时使用如下命令查看监听的数据库信息:当发现status为3时,使用ping、telnet、psql -h进行测试网络连通性。关闭防火墙。

postgres=# show pool_nodes;
 node_id |   hostname   | port | status | lb_weight |  role   
---------+--------------+------+--------+-----------+---------
 0       | 192.168.1.45 | 5432 | 2      | 0.500000  | primary
 1       | 192.168.1.50 | 5432 | 2      | 0.500000  | standby

  当然,可以启动主从数据库的日志级别为 all。那么对数据的一切操作,都可以查看到。此时可以使用脚本测试一下。就可以查看主从的日志。看看是否都有日志记录。

for i in {1..100}; do echo $i; psql -p 9999 -U postgres -h 192.168.1.45 -d postgres -c "select * from test"; done

  1.5 查看pgpool的状态。参考手册:http://pgpool.projects.pgfoundry.org/pgpool-II/doc/pgpool-zh_cn.html#show-commands

  之前安装的regclass就是通过psql查看pgpool状态的工具。可以运行下列命令查看:

pgpool-II 通过 SHOW 命令提供一些信息。SHOW 是一个真实的 SQL 语句, 但是如果该命令查询 pgpool-II 信息的话,pgpool-II 解释了该命令。可选项如下:

pool_status, 获取配置
pool_nodes, 获取节点信息
pool_processes, 获取pgPool-II 进程信息
pool_pools, 获取pgPool-II 所有的连接池信息
pool_version, 获取pgPool_II 版本信息

  比如:pool_processes。查看进程池的情况。可以根据需要修改pgpool中的设置。

postgres=# show pool_processes;
 pool_pid |     start_time      | database | username |     create_time     | pool_counter 
----------+---------------------+----------+----------+---------------------+--------------
 30093    | 2015-09-18 17:28:49 | postgres | postgres | 2015-09-18 17:35:24 | 1
 30947    | 2015-09-18 17:35:31 |          |          |                     | 
 31078    | 2015-09-18 17:36:55 |          |          |                     | 
 30087    | 2015-09-18 17:28:48 |          |          |                     | 
 30088    | 2015-09-18 17:28:48 |          |          |                     | 
 30090    | 2015-09-18 17:28:49 |          |          |                     | 
 30089    | 2015-09-18 17:28:48 |          |          |                     | 
 30091    | 2015-09-18 17:28:49 |          |          |                     | 
 30092    | 2015-09-18 17:28:49 |          |          |                     | 
 30086    | 2015-09-18 17:28:48 |          |          |                     | 

 

posted @ 2015-09-18 20:01  陈贞  阅读(2894)  评论(0编辑  收藏  举报