postgresql+pgpool双机热备-高可用

一、 主机

主机	IP	服务
master	192.168.0.56	postgresql、postgis、pgpool
slave	192.168.0.58	postgresql、postgis、pgpool

二、安装postgresql

过程忽略

三、配置白名单与流复制

1. master配置

PostgreSQL流复制默认是异步的。在主服务器上提交事务和从服务器上变化可见之间有一个小的延迟，这个延迟远小于基于文件日志传送，通常1秒能完成。如果主服务器突然崩溃，可能会有少量数据丢失。
同步复制必须等主服务器和从服务器都写完WAL后才能提交事务。这样在一定程度上会增加事务的响应时间。
配置同步复制仅需要一个额外的配置步骤： synchronous_standby_names 必须设置为一个非空值。synchronous_commit 也必须设置为 on。
这里部署的是异步的流复制

1.1 配置白名单

vim /pgdata/pg_hba.conf

# 在配置文件末尾添加
pg_hba.conf
host    all             all             0.0.0.0/0               md5
host    replication     replica         192.168.0.58/32         md5

1.2 修改配置文件

vim /pgdata/postgresql.conf

# postgresql.conf
data_directory = '/pgdata'                # 自定义data目录
archive_mode = on                         # 允许归档
archive_command = 'cp %p /pg_archive/%f'
wal_level = hot_standby                   # 选择热备
max_wal_senders = 16                      # 最多多少各流复制链接
wal_keep_segments = 256                   # 流复制保留最多的xlog数
wal_sender_timeout = 60s                  # 流复制主机发送数据超时时间
max_connections = 1000                    # 从库的max_connections必须大于主库的

full_page_writes = on                     # 使用pg_rewind命令同步数据库要用
wal_log_hints = on                        # 使用pg_rewind命令同步数据库要用
hot_standby = on                          # 使用pg_rewind命令同步数据库要用

listen_addresses = '*'                    # 修改监听

1.3 创建data目录，赋权并修改启动文件

mkdir -p /pgdata && chown postgres:postgres /pgdata && chmod 700 /pgdata
mkdir -p /pg_archive && chown postgres:postgres /pg_archive && chmod 700 pg_archive
初始化数据库：su - postgres -c "/usr/pgsql-10/bin/initdb -D /pgdata

1.4 修改启动文件

vim /usr/lib/systemd/system/postgresql-10.service

1.5 启动postgresql并创建replica用户，密码replica

systemctl start postgresql-10.service
su postgres
psql
CREATE ROLE replica login replication encrypted password 'replica';

1.6 在slave节点测试链接主节点

slave节点执行：psql -h 192.168.0.56 -U postgres (首先设置好postgres用户密码后测试)

2 slave配置

2.1 配置白名单

vim /pgdata/pg_hba.conf

# 在配置文件末尾添加
pg_hba.conf
host    all             all             0.0.0.0/0               md5
host    replication     replica         192.168.0.56/32         md5

2.2 创建data目录

mkdir -p /pgdata && chown postgres:postgres /pgdata && chmod 700 /pgdata
mkdir -p /pg_archive && chown postgres:postgres /pg_archive && chmod 700 pg_archive

2.3 备份数据

# 切换用户
su postgres
# 备份主库的数据库到从库/pgdata
pg_basebackup -h 192.168.0.56 -U replica -D /pgdata -X stream –P

2.4 修改启动文件

vim /usr/lib/systemd/system/postgresql-10.service

2.5 配置recovery.conf

su postgres
cp /usr/pgsql-10/share/recovery.conf.sample /pgdata/recovery.conf
vim /pgdata/recovery.conf

# recovery.conf
standby_mode = on        # 该节点为从
primary_conninfo = 'host=192.168.123.180 port=5432 user=replica password=replica'    #主服务器的ip、user
recovery_target_timeline = 'latest'
trigger_file = '/tmp/trigger_file0'

2.6 配置postgresql.conf

vim /pgdata/postgresql.conf

# postgresql.conf
data_directory = '/pgdata'                # 自定义data目录
max_connections = 10000                    # 从库的max_connections必须大于主库的
max_standby_streaming_delay = 30s
wal_receiver_status_interval = 10s
hot_standby_feedback = on

full_page_writes = on                     # 使用pg_rewind命令同步数据库要用
wal_log_hints = on                        # 使用pg_rewind命令同步数据库要用
hot_standby = on                          # 使用pg_rewind命令同步数据库要用

listen_addresses = '*'

2.7 启动postgresql

systemctl start postgresql-10.services

3 验证流复制

3.1 在master上登陆psql

查看状态:

select client_addr,sync_state from pg_stat_replication;

3.2 创建test库

Create database test;

3.3 slave上登陆psql

查看库

发现已同步。

4 主从切换及恢复

4.1 模拟主故障

关闭postgresql

4.2 升级从库为主库

[root@test3 log]# su postgres
bash-4.2$ /usr/pgsql-10/bin/pg_ctl promote -D /pgdata
waiting for server to promote.... 完成
server promoted
bash-4.2$

升级主库后，recovery.conf 会变成recovery.done， 配置文件失效

4.3 通过pg_rewind命令同步数据，主库变成从库

[root@test2 log]# su postgres
# 同步主库（原备库）数据   ！！！ 同步前，本地postgresl要处于关闭状态
bash-4.2$ /usr/pgsql-10/bin/pg_rewind --target-pgdata=/pgdata --source-server='host=192.168.0.58  port=5432 user=postgres password=zhjx123 dbname=postgres' -P               
 
.....
received chunk for file "pg_wal/00000003000000000000000E", offset 10000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 11000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 12000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 13000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 14000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 15000000, size 1000000
received chunk for file "pg_wal/00000003000000000000000E", offset 16000000, size 777216
received chunk for file "pg_xact/0000", offset 0, size 8192
received chunk for file "postgresql.auto.conf", offset 0, size 88
received chunk for file "postgresql.conf", offset 0, size 23826
received chunk for file "recovery.done", offset 0, size 5986
已复制100084/100084 kB (100%)
正在创建备份标签并且更新控制文件
正在同步目标数据目录
同步数据到磁盘...成功
完成！
bash-4.2$ su root
[root@test2 pgdata]# ls
backup_label.old  log           pg_ident.conf  pg_replslot   pg_stat_tmp  PG_VERSION            postgresql.conf
base              pg_commit_ts  pg_logical     pg_serial     pg_subtrans  pg_wal                postmaster.opts
current_logfiles  pg_dynshmem   pg_multixact   pg_snapshots  pg_tblspc    pg_xact               postmaster.pid
global            pg_hba.conf   pg_notify      pg_stat       pg_twophase  postgresql.auto.conf  recovery.done

修改修改recovery.done

[root@test2 pgdata]# mv recovery.done recovery.conf

修改主库连接地址

启动本地数据库

[root@test2 pgdata]# systemctl start postgresql-10.serivce

4.4 检测集群状态

在主库（原从库）执行查询命令

查看状态:
select client_addr,sync_state from pg_stat_replication;

postgres=# select client_addr,sync_state from pg_stat_replication;
client_addr | sync_state
--------------+------------
192.168.0.56| async
(1 row)

postgres=#

四、配置pgpool (经测试不稳定)

参考：https://www.jianshu.com/p/ef183d0a9213
pgpool-II是PostgreSQL服务器之间一种有效的中间件和PostgreSQL数据库客户端。它提供了以下功能。
连接池
pgpool-II保存到PostgreSQL服务器的连接，当一个相同新连接(如用户名、数据库、协议版本)进来时，重用他们。它减少了连接开销，提高了系统的整体吞吐量。
复制
pgpool-II可以管理多个PostgreSQL服务器。使用复制功能可以使2个或更多的物理磁盘上创建一个实时备份，这样服务不会因服务器的磁盘故障而中断。
负载平衡
如果数据库是复制的，在任何服务器上执行一个SELECT查询会返回相同的结果。pgpool-II复制特性的优势在于减少每个PostgreSQL服务器上的负载，因为它可以使用分布在多个服务器之间进行SELECT查询，从而提高系统的整体吞吐量。最好是查询和PostgreSQL服务器数量成一定比例，多用户同时执行多查询达到负载均衡最好的效果。
限制连接数
PostgreSQL的最大并发连接数有一定限制的，当超过限制的连接数后，连接会被拒绝。然而，设置增加最大连接数又会增加资源消耗，影响系统性能。pgpool-II也有最大连接数限制，但超过的连接进来时是进行立即排队，而不是返回一个错误。
pgpool-II交互PostgreSQL的后端和前端协议时，起着继电器的作用。因此，数据库应用程序(前端)认为pgpool-II是真实的PostgreSQL服务器，服务器(后端)认为pgpool-II是它的客户端之一。因为pgpool-II在服务器和客户端是透明的，所以pgpool-II可以使用现有的数据库应用程序而做到几乎不修改它们。

1 各节点免密登录

关闭系统selinux防火墙，否则失败，同事修改SSH免密登录，使配置支持。
安装之前先配置密钥使master和slave这两台虚拟机的postgres用户能免密连接,

先修改postgres的密码，在root用户下

passwd postgres
# 新密码 123456

# Master到slave1的免密码登陆：
# 在master上切换至postgres用户，生成密钥
su postgres ssh-keygen -t rsa
然后全输入回车
 
# 切换到postgres用户：
su postgres ssh-copy-id -i /var/lib/pgsql/.ssh/id_rsa 192.168.0.58
然后ssh 192.168.0.58 成功，实现master到slave的免密码登陆
-----------------------------------------------------------------------------
# Slave1到master的免密码登陆：
流程同上

2 安装pgpool（主从节点都安装）

yum install pgpool-II-10.x86_64

3 配置（主从节点均配置）

3.1 配置pool_hba.conf

pool_hba.conf是对登录用户进行验证的，要和pg的pg_hba.conf保持一致，要么都是trust，要么都是md5验证方式，这里采用了md5验证方式如下设置：

[postgres@master ~]$ cd /opt/pgpool/etc
[postgres@etc~]$ cp pool_hba.conf.sample pool_hba.conf
[postgres@etc~]$ vim pool_hba.conf
#编辑内容如下
# "local" is for Unix domain socket connections only
local   all         all                           md5
# IPv4 local connections:
host    all         all         0.0.0.0/0            md5
host    all         all         0/0                md5

3.2 配置pcp.conf

pcp.conf配置用于pgpool自己登陆管理使用的，一些操作pgpool的工具会要求提供密码等，配置如下：

[postgres@master ~]$ cd /etc/pgpool-II-10
[postgres@etc~]$ cp pcp.conf.sample pcp.conf
# 使用pg_md5生成配置的用户名密码，nariadmin 是pgpool的用户密码，随意自定义
[postgres@etc~]$ pg_md5 nariadmin   
6b07583ba8af8e03043a1163147faf6a
# pcp.conf是pgpool管理器自己的用户名和密码，用于管理集群。
[postgres@etc~]$ vim pcp.conf
# 编辑内容如下。postgres也是定义的用户，自定义
postgres:6b07583ba8af8e03043a1163147faf6a
# 保存退出！
# 在pgpool中添加pg数据库的用户名和密码
[postgres@etc~]$ pg_md5 -p -m -u postgres pool_passwd
# 数据库登录用户是postgres,这里输入登录密码，不能出错
# 输入密码后，在/etc/pgpool-II-10 目录下会生成一个pool_passwd文件

3.3 配置系统命令权限

配置ifconfig, arping 执行权限 ，执行failover_stream.sh需要用到，可以让其他普通用户执行。

[root@master ~]# chmod u+s /sbin/ifconfig 
[root@master ~]# chmod u+s /usr/sbin

3.4 配置master上的pgpool.conf

[postgres@master ~]$ cd /opt/pgpool/etc
[postgres@etc~]$ cp pgpool.conf.sample pgpool.conf
[postgres@etc~]$ vim pgpool.conf

编辑内容如下

# ----------------------------
# 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 -
# 修改监听
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)
listen_backlog_multiplier = 2
                                   # Set the backlog parameter of listen(2) to
                                   # num_init_children * listen_backlog_multiplier.
                                   # (change requires restart)
serialize_accept = off
                                   # whether to serialize accept() call to avoid thundering herd problem
                                   # (change requires restart)
reserved_connections = 0
                                   # Number of reserved connections.
                                   # Pgpool-II does not accept connections if over
                                   # num_init_chidlren - reserved_connections.

# - pgpool Communication Manager Connection Settings -
# 修改监听
pcp_listen_addresses = '*'
                                   # Host name or IP address for pcp process to listen on:
                                   # '*' for all, '' for no TCP/IP connections
                                   # (change requires restart)
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 -
# pgpool集群后端主机信息
# 修改为本端主机名，要在hosts中加入解析
backend_hostname0 = 'test2'
                                   # 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)
# 修改postgresql的数据目录
backend_data_directory0 = '/pgdata'
                                   # Data directory for backend 0
backend_flag0 = 'ALLOW_TO_FAILOVER'
                                   # Controls various backend behavior
                                   # ALLOW_TO_FAILOVER, DISALLOW_TO_FAILOVER
                                   # or ALWAYS_MASTER
# 添加内容，
backend_hostname1 = 'test3'
backend_port1 = 5432
backend_weight1 = 1
backend_data_directory1 = '/pgdata'
backend_flag1 = 'ALLOW_TO_FAILOVER'
# 添加结束

backend_application_name0 = 'server0'
                                   # walsender's application_name, used for "show pool_nodes" command
#backend_hostname1 = 'host2'
#backend_port1 = 5433
#backend_weight1 = 1
#backend_data_directory1 = '/data1'
#backend_flag1 = 'ALLOW_TO_FAILOVER'
#backend_application_name1 = 'server1'

# - Authentication -
# 激活pgpool认证方式
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.

allow_clear_text_frontend_auth = off
                                   # Allow Pgpool-II to use clear text password authentication
                                   # with clients, when pool_passwd does not
                                   # contain the user password


# - 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)

ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL'
                                   # Allowed SSL ciphers
                                   # (change requires restart)
ssl_prefer_server_ciphers = off
                                   # Use server's SSL cipher preferences,
                                   # rather than the client's
                                   # (change requires restart)
ssl_ecdh_curve = 'prime256v1'
                                   # Name of the curve to use in ECDH key exchange
ssl_dh_params_file = ''
                                   # Name of the file containing Diffie-Hellman parameters used
                                   # for so-called ephemeral DH family of SSL cipher.

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

# - Concurrent session and pool size -

num_init_children = 32
                                   # Number of concurrent sessions allowed
                                   # (change requires restart)
max_pool = 4
                                   # Number of connection pool caches per connection
                                   # (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 -

log_line_prefix = '%t: pid %p: '   # printf-style string to output at beginning of each log line.

log_connections = off
                                   # Log connections
log_hostname = off
                                   # Hostname will be shown in ps status
                                   # and in logs if connections are logged
log_statement = off
                                   # Log all statements
log_per_node_statement = off
                                   # Log all statements
                                   # with node and backend informations
log_client_messages = off
                                   # Log any client messages
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 -

#log_error_verbosity = default          # terse, default, or verbose messages

#client_min_messages = notice           # values in order of decreasing detail:
                                        #   debug5
                                        #   debug4
                                        #   debug3
                                        #   debug2
                                        #   debug1
                                        #   log
                                        #   notice
                                        #   warning
                                        #   error

#log_min_messages = warning             # values in order of decreasing detail:
                                        #   debug5
                                        #   debug4
                                        #   debug3
                                        #   debug2
                                        #   debug1
                                        #   info
                                        #   notice
                                        #   warning
                                        #   error
                                        #   log
                                        #   fatal
                                        #   panic

#------------------------------------------------------------------------------
# FILE LOCATIONS
#------------------------------------------------------------------------------
# pid文件路径  这里不做修改
pid_file_name = '/var/run/pgpool-II-10/pgpool.pid'
                                   # PID file name
                                   # Can be specified as relative to the"
                                   # location of pgpool.conf file or
                                   # as an absolute path
                                   # (change requires restart)
# pgpool集群状态信息文件，这里保持默认
logdir = '/var/log/pgpool-II-10'
                                   # 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
#------------------------------------------------------------------------------
# 复制模式保持关闭
replication_mode = off
                                   # Activate replication mode
                                   # (change requires restart)
replicate_select = off
                                   # Replicate SELECT statements
                                   # when in replication 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
#------------------------------------------------------------------------------
# 激活负载均衡模式
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 = 'currval,lastval,nextval,setval'
                                   # Comma separated list of function names
                                   # that write to database
                                   # Regexp are accepted

black_query_pattern_list = ''
                                   # Semicolon separated list of query patterns
                                   # that should be sent to primary node
                                   # Regexp are accepted
                                   # valid for streaming replicaton mode only.

database_redirect_preference_list = ''
                                   # comma separated list of pairs of database and node id.
                                   # example: postgres:primary,mydb[0-4]:1,mydb[5-9]:2'
                                   # valid for streaming replicaton mode only.
app_name_redirect_preference_list = ''
                                   # comma separated list of pairs of app name and node id.
                                   # example: 'psql:primary,myapp[0-4]:1,myapp[5-9]:standby'
                                   # valid for streaming replicaton mode only.
allow_sql_comments = off
                                   # if on, ignore SQL comments when judging if load balance or
                                   # query cache is possible.
                                   # If off, SQL comments effectively prevent the judgment
                                   # (pre 3.4 behavior).

disable_load_balance_on_write = 'transaction'
                                   # Load balance behavior when write query is issued
                                   # in an explicit transaction.
                                   # Note that any query not in an explicit transaction
                                   # is not affected by the parameter.
                                   # 'transaction' (the default): if a write query is issued,
                                   # subsequent read queries will not be load balanced
                                   # until the transaction ends.
                                   # 'trans_transaction': if a write query is issued,
                                   # subsequent read queries in an explicit transaction
                                   # will not be load balanced until the session ends.
                                   # 'always': if a write query is issued, read queries will
                                   # not be load balanced until the session ends.

statement_level_load_balance = off
                                   # Enables statement level load balancing

#------------------------------------------------------------------------------
# MASTER/SLAVE MODE
#------------------------------------------------------------------------------
# 激活主从模式
master_slave_mode = on
                                   # Activate master/slave mode
                                   # (change requires restart)
master_slave_sub_mode = 'stream'
                                   # Master/slave sub mode
                                   # Valid values are combinations stream, slony
                                   # or logical. Default is stream.
                                   # (change requires restart)

# - Streaming -
# 流复制检查周期
sr_check_period = 5
                                   # Streaming replication check period
                                   # Disabled (0) by default
# 流复制检查用户，replica是数据库的用户
sr_check_user = 'replica'
                                   # Streaming replication check user
                                   # This is necessary even if you disable
                                   # streaming replication delay check with
                                   # sr_check_period = 0
# 流复制检查用户密码
sr_check_password = 'replica'
                                   # Password for streaming replication check user.
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty password
# 流复制检查数据库
sr_check_database = 'postgres'
                                   # Database name for streaming replication check
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 = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character

#------------------------------------------------------------------------------
# HEALTH CHECK GLOBAL PARAMETERS
#------------------------------------------------------------------------------
# 激活健康检查，周期10s
health_check_period = 10
                                   # Health check period
                                   # Disabled (0) by default
health_check_timeout = 20
                                   # Health check timeout
                                   # 0 means no timeout
# 健康检查用户，数据库管理员用户
health_check_user = 'postgres'
                                   # Health check user
# 健康检查用户密码
health_check_password = 'zhjx123'
                                   # Password for health check user
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty password
# 健康检查数据库
# 必须设置，否则primary数据库down了，pgpool不知道，不能及时切换。从库流复制还在连接数据，报连接失败。
# 只有下次使用pgpool登录时，发现连接不上，然后报错，这时候，才知道挂了，pgpool进行切换。
health_check_database = 'postgres'
                                   # Database name for health check. If '', tries 'postgres' frist, then 'template1'

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.
connect_timeout = 10000
                                   # Timeout value in milliseconds before giving up to connect to backend.
                                   # Default is 10000 ms (10 second). Flaky network user may want to increase
                                   # the value. 0 means no timeout.
                                   # Note that this value is not only used for health check,
                                   # but also for ordinary conection to backend.

#------------------------------------------------------------------------------
# HEALTH CHECK PER NODE PARAMETERS (OPTIONAL)
#------------------------------------------------------------------------------
#health_check_period0 = 0
#health_check_timeout0 = 20
#health_check_user0 = 'nobody'
#health_check_password0 = ''
#health_check_database0 = ''
#health_check_max_retries0 = 0
#health_check_retry_delay0 = 1
#connect_timeout0 = 10000

#主备切换的命令行配置
#------------------------------------------------------------------------------
# FAILOVER AND FAILBACK
#------------------------------------------------------------------------------
# 启动故障转移

failover_command = '/etc/pgpool-II-10/failover_stream.sh %H'
                                   # Executes this command at failover
                                   # Special values:
                                   #   %d = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character
failback_command = ''
                                   # Executes this command at failback.
                                   # Special values:
                                   #   %d = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character

failover_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.

detach_false_primary = off
                                   # Detach false primary if on. Only
                                   # valid in streaming replicaton
                                   # mode and with PostgreSQL 9.6 or
                                   # after.

search_primary_node_timeout = 300
                                   # Timeout in seconds to search for the
                                   # primary node when a failover occurs.
                                   # 0 means no timeout, keep searching
                                   # for a primary node forever.

auto_failback = off
                                   # Dettached backend node reattach automatically
                                   # if replication_state is 'streaming'.
auto_failback_interval = 60
                                   # Min interval of executing auto_failback in
                                   # seconds.

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

recovery_user = 'nobody'
                                   # Online recovery user
recovery_password = ''
                                   # Online recovery password
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty 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 -
# 激活看门狗
use_watchdog = on
                                    # 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 -
# 本端地址
wd_hostname = 'test2'
                                    # Host name or IP address of this watchdog
                                    # (change requires restart)
wd_port = 9000
                                    # port number for watchdog service
                                    # (change requires restart)
wd_priority = 1
                                    # priority of this watchdog in leader election
                                    # (change requires restart)

wd_authkey = ''
                                    # Authentication key for watchdog communication
                                    # (change requires restart)

wd_ipc_socket_dir = '/tmp'
                                    # Unix domain socket path for watchdog IPC socket
                                    # The Debian package defaults to
                                    # /var/run/postgresql
                                    # (change requires restart)


# - Virtual IP control Setting -
# 激活虚拟VIP，vip在hosts里面设置解析，否则直接填写ip
delegate_IP = 'vip'
                                    # delegate IP address
                                    # If this is empty, virtual IP never bring up.
                                    # (change requires restart)
if_cmd_path = '/sbin'
                                    # path to the directory where if_up/down_cmd exists
                                    # If if_up/down_cmd starts with "/", if_cmd_path will be ignored.
                                    # (change requires restart)
#if_up_cmd = '/usr/bin/sudo /sbin/ip addr add $_IP_$/24 dev eth0 label eth0:0'
# 执行添加vip地址命令
if_up_cmd = '/sbin/ifconfig ens192:0 inet $_IP_$ netmask 255.255.254.0'
                                    # startup delegate IP command
                                    # (change requires restart)
#if_down_cmd = '/usr/bin/sudo /sbin/ip addr del $_IP_$/24 dev eth0'
# 执行删除vip地址命令
if_down_cmd = '/sbin/ifconfig ens192:0 down'
                                    # shutdown delegate IP command
                                    # (change requires restart)
arping_path = '/usr/sbin'
                                    # arping command path
                                    # If arping_cmd starts with "/", if_cmd_path will be ignored.
                                    # (change requires restart)
arping_cmd = '/usr/bin/sudo /usr/sbin/arping -U $_IP_$ -w 1 -I ens192'
                                    # 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)
wd_de_escalation_command = ''
                                    # Executes this command when master pgpool resigns from being master.
                                    # (change requires restart)

# - Watchdog consensus settings for failover -

failover_when_quorum_exists = on
                                    # Only perform backend node failover
                                    # when the watchdog cluster holds the quorum
                                    # (change requires restart)

failover_require_consensus = on
                                    # Perform failover when majority of Pgpool-II nodes
                                    # aggrees on the backend node status change
                                    # (change requires restart)

allow_multiple_failover_requests_from_node = off
                                    # A Pgpool-II node can cast multiple votes
                                    # for building the consensus on failover
                                    # (change requires restart)

enable_consensus_with_half_votes = off
                                    # apply majority rule for consensus and quorum computation
                                    # at 50% of votes in a cluster with even number of nodes.
                                    # when enabled the existence of quorum and consensus
                                    # on failover is resolved after receiving half of the
                                    # total votes in the cluster, otherwise both these
                                    # decisions require at least one more vote than
                                    # half of the total votes.
                                    # (change requires restart)

# - Lifecheck Setting -

# -- common --

wd_monitoring_interfaces_list = ''  # Comma separated list of interfaces names to monitor.
                                    # if any interface from the list is active the watchdog will
                                    # consider the network is fine
                                    # 'any' to enable monitoring on all interfaces except loopback
                                    # '' to disable monitoring
                                    # (change requires restart)


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

# -- heartbeat mode --
# 激活心跳侦测
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)
# 对端地址
heartbeat_destination0 = 'test3'
                                    # 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)
# 执行侦测的网卡
heartbeat_device0 = 'ens192'
                                    # 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
                                    # Leaving it empty will make Pgpool-II to first look for the
                                    # Password in pool_passwd file before using the empty password
                                    # (change requires restart)

# - Other pgpool Connection Settings -
# 激活其他pgpool服务器节点连接信息

#other_pgpool_hostname0 = 'host0'
other_pgpool_hostname0 = 'test3'
                                    # Host name or IP address to connect to for other pgpool 0
                                    # (change requires restart)
# pgpool连接端口改为9999
other_pgpool_port0 = 9999
                                    # Port number for other pgpool 0
                                    # (change requires restart)
other_wd_port0 = 9000
                                    # Port number for other 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 = catalog
                                   # Temporary table check method. catalog, trace or none.
                                   # Default is catalog.

check_unlogged_table = on
                                   # If on, enable unlogged 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 unlogged tables
                                   # and you want to save access to primary/master, you could turn this off.
                                   # Default is on.
enable_shared_relcache = on
                                   # If on, relation cache stored in memory cache,
                                   # the cache is shared among child process.
                                   # Default is on.
                                   # (change requires restart)

relcache_query_target = master     # Target node to send relcache queries. Default is master (primary) node.
                                   # If load_balance_node is specified, queries will be sent to load balance node.
#------------------------------------------------------------------------------
# IN MEMORY QUERY MEMORY CACHE
#------------------------------------------------------------------------------
memory_cache_enabled = off
                                   # If on, use the memory cache functionality, off by default
                                   # (change requires restart)
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

3.5 配置slave上的pgpool.conf

# ----------------------------
# 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 -
# 修改监听
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)
listen_backlog_multiplier = 2
                                   # Set the backlog parameter of listen(2) to
                                   # num_init_children * listen_backlog_multiplier.
                                   # (change requires restart)
serialize_accept = off
                                   # whether to serialize accept() call to avoid thundering herd problem
                                   # (change requires restart)
reserved_connections = 0
                                   # Number of reserved connections.
                                   # Pgpool-II does not accept connections if over
                                   # num_init_chidlren - reserved_connections.

# - pgpool Communication Manager Connection Settings -
# 修改监听
pcp_listen_addresses = '*'
                                   # Host name or IP address for pcp process to listen on:
                                   # '*' for all, '' for no TCP/IP connections
                                   # (change requires restart)
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 -
# pgpool集群后端主机信息
# 修改为本端主机名，要在hosts中加入解析
backend_hostname0 = 'test2'
                                   # 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)
# 修改postgresql的数据目录
backend_data_directory0 = '/pgdata'
                                   # Data directory for backend 0
backend_flag0 = 'ALLOW_TO_FAILOVER'
                                   # Controls various backend behavior
                                   # ALLOW_TO_FAILOVER, DISALLOW_TO_FAILOVER
                                   # or ALWAYS_MASTER
# 添加内容，
backend_hostname1 = 'test3'
backend_port1 = 5432
backend_weight1 = 1
backend_data_directory1 = '/pgdata'
backend_flag1 = 'ALLOW_TO_FAILOVER'
# 添加结束

backend_application_name0 = 'server0'
                                   # walsender's application_name, used for "show pool_nodes" command
#backend_hostname1 = 'host2'
#backend_port1 = 5433
#backend_weight1 = 1
#backend_data_directory1 = '/data1'
#backend_flag1 = 'ALLOW_TO_FAILOVER'
#backend_application_name1 = 'server1'

# - Authentication -
# 激活pgpool认证方式
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.

allow_clear_text_frontend_auth = off
                                   # Allow Pgpool-II to use clear text password authentication
                                   # with clients, when pool_passwd does not
                                   # contain the user password


# - 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)

ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL'
                                   # Allowed SSL ciphers
                                   # (change requires restart)
ssl_prefer_server_ciphers = off
                                   # Use server's SSL cipher preferences,
                                   # rather than the client's
                                   # (change requires restart)
ssl_ecdh_curve = 'prime256v1'
                                   # Name of the curve to use in ECDH key exchange
ssl_dh_params_file = ''
                                   # Name of the file containing Diffie-Hellman parameters used
                                   # for so-called ephemeral DH family of SSL cipher.

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

# - Concurrent session and pool size -

num_init_children = 32
                                   # Number of concurrent sessions allowed
                                   # (change requires restart)
max_pool = 4
                                   # Number of connection pool caches per connection
                                   # (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 -

log_line_prefix = '%t: pid %p: '   # printf-style string to output at beginning of each log line.

log_connections = off
                                   # Log connections
log_hostname = off
                                   # Hostname will be shown in ps status
                                   # and in logs if connections are logged
log_statement = off
                                   # Log all statements
log_per_node_statement = off
                                   # Log all statements
                                   # with node and backend informations
log_client_messages = off
                                   # Log any client messages
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 -

#log_error_verbosity = default          # terse, default, or verbose messages

#client_min_messages = notice           # values in order of decreasing detail:
                                        #   debug5
                                        #   debug4
                                        #   debug3
                                        #   debug2
                                        #   debug1
                                        #   log
                                        #   notice
                                        #   warning
                                        #   error

#log_min_messages = warning             # values in order of decreasing detail:
                                        #   debug5
                                        #   debug4
                                        #   debug3
                                        #   debug2
                                        #   debug1
                                        #   info
                                        #   notice
                                        #   warning
                                        #   error
                                        #   log
                                        #   fatal
                                        #   panic

#------------------------------------------------------------------------------
# FILE LOCATIONS
#------------------------------------------------------------------------------
# pid文件路径  这里不做修改
pid_file_name = '/var/run/pgpool-II-10/pgpool.pid'
                                   # PID file name
                                   # Can be specified as relative to the"
                                   # location of pgpool.conf file or
                                   # as an absolute path
                                   # (change requires restart)
# pgpool集群状态信息文件，这里保持默认
logdir = '/var/log/pgpool-II-10'
                                   # 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
#------------------------------------------------------------------------------
# 复制模式保持关闭
replication_mode = off
                                   # Activate replication mode
                                   # (change requires restart)
replicate_select = off
                                   # Replicate SELECT statements
                                   # when in replication 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
#------------------------------------------------------------------------------
# 激活负载均衡模式
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 = 'currval,lastval,nextval,setval'
                                   # Comma separated list of function names
                                   # that write to database
                                   # Regexp are accepted

black_query_pattern_list = ''
                                   # Semicolon separated list of query patterns
                                   # that should be sent to primary node
                                   # Regexp are accepted
                                   # valid for streaming replicaton mode only.

database_redirect_preference_list = ''
                                   # comma separated list of pairs of database and node id.
                                   # example: postgres:primary,mydb[0-4]:1,mydb[5-9]:2'
                                   # valid for streaming replicaton mode only.
app_name_redirect_preference_list = ''
                                   # comma separated list of pairs of app name and node id.
                                   # example: 'psql:primary,myapp[0-4]:1,myapp[5-9]:standby'
                                   # valid for streaming replicaton mode only.
allow_sql_comments = off
                                   # if on, ignore SQL comments when judging if load balance or
                                   # query cache is possible.
                                   # If off, SQL comments effectively prevent the judgment
                                   # (pre 3.4 behavior).

disable_load_balance_on_write = 'transaction'
                                   # Load balance behavior when write query is issued
                                   # in an explicit transaction.
                                   # Note that any query not in an explicit transaction
                                   # is not affected by the parameter.
                                   # 'transaction' (the default): if a write query is issued,
                                   # subsequent read queries will not be load balanced
                                   # until the transaction ends.
                                   # 'trans_transaction': if a write query is issued,
                                   # subsequent read queries in an explicit transaction
                                   # will not be load balanced until the session ends.
                                   # 'always': if a write query is issued, read queries will
                                   # not be load balanced until the session ends.

statement_level_load_balance = off
                                   # Enables statement level load balancing

#------------------------------------------------------------------------------
# MASTER/SLAVE MODE
#------------------------------------------------------------------------------
# 激活主从模式
master_slave_mode = on
                                   # Activate master/slave mode
                                   # (change requires restart)
master_slave_sub_mode = 'stream'
                                   # Master/slave sub mode
                                   # Valid values are combinations stream, slony
                                   # or logical. Default is stream.
                                   # (change requires restart)

# - Streaming -
# 流复制检查周期
sr_check_period = 5
                                   # Streaming replication check period
                                   # Disabled (0) by default
# 流复制检查用户，replica是数据库的用户
sr_check_user = 'replica'
                                   # Streaming replication check user
                                   # This is necessary even if you disable
                                   # streaming replication delay check with
                                   # sr_check_period = 0
# 流复制检查用户密码
sr_check_password = 'replica'
                                   # Password for streaming replication check user.
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty password
# 流复制检查数据库
sr_check_database = 'postgres'
                                   # Database name for streaming replication check
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 = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character

#------------------------------------------------------------------------------
# HEALTH CHECK GLOBAL PARAMETERS
#------------------------------------------------------------------------------
# 激活健康检查，周期10s
health_check_period = 10
                                   # Health check period
                                   # Disabled (0) by default
health_check_timeout = 20
                                   # Health check timeout
                                   # 0 means no timeout
# 健康检查用户，数据库管理员用户
health_check_user = 'postgres'
                                   # Health check user
# 健康检查用户密码
health_check_password = 'zhjx123'
                                   # Password for health check user
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty password
# 健康检查数据库
# 必须设置，否则primary数据库down了，pgpool不知道，不能及时切换。从库流复制还在连接数据，报连接失败。
# 只有下次使用pgpool登录时，发现连接不上，然后报错，这时候，才知道挂了，pgpool进行切换。
health_check_database = 'postgres'
                                   # Database name for health check. If '', tries 'postgres' frist, then 'template1'

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.
connect_timeout = 10000
                                   # Timeout value in milliseconds before giving up to connect to backend.
                                   # Default is 10000 ms (10 second). Flaky network user may want to increase
                                   # the value. 0 means no timeout.
                                   # Note that this value is not only used for health check,
                                   # but also for ordinary conection to backend.

#------------------------------------------------------------------------------
# HEALTH CHECK PER NODE PARAMETERS (OPTIONAL)
#------------------------------------------------------------------------------
#health_check_period0 = 0
#health_check_timeout0 = 20
#health_check_user0 = 'nobody'
#health_check_password0 = ''
#health_check_database0 = ''
#health_check_max_retries0 = 0
#health_check_retry_delay0 = 1
#connect_timeout0 = 10000

#主备切换的命令行配置
#------------------------------------------------------------------------------
# FAILOVER AND FAILBACK
#------------------------------------------------------------------------------
# 启动故障转移

failover_command = '/etc/pgpool-II-10/failover_stream.sh %H'
                                   # Executes this command at failover
                                   # Special values:
                                   #   %d = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character
failback_command = ''
                                   # Executes this command at failback.
                                   # Special values:
                                   #   %d = failed node id
                                   #   %h = failed node host name
                                   #   %p = failed node port number
                                   #   %D = failed node database cluster path
                                   #   %m = new master node id
                                   #   %H = new master node hostname
                                   #   %M = old master node id
                                   #   %P = old primary node id
                                   #   %r = new master port number
                                   #   %R = new master database cluster path
                                   #   %N = old primary node hostname
                                   #   %S = old primary node port number
                                   #   %% = '%' character

failover_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.

detach_false_primary = off
                                   # Detach false primary if on. Only
                                   # valid in streaming replicaton
                                   # mode and with PostgreSQL 9.6 or
                                   # after.

search_primary_node_timeout = 300
                                   # Timeout in seconds to search for the
                                   # primary node when a failover occurs.
                                   # 0 means no timeout, keep searching
                                   # for a primary node forever.

auto_failback = off
                                   # Dettached backend node reattach automatically
                                   # if replication_state is 'streaming'.
auto_failback_interval = 60
                                   # Min interval of executing auto_failback in
                                   # seconds.

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

recovery_user = 'nobody'
                                   # Online recovery user
recovery_password = ''
                                   # Online recovery password
                                   # Leaving it empty will make Pgpool-II to first look for the
                                   # Password in pool_passwd file before using the empty 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 -
# 激活看门狗
use_watchdog = on
                                    # 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 -
# 本端地址，与master节点相反
wd_hostname = 'test3'
                                    # Host name or IP address of this watchdog
                                    # (change requires restart)
wd_port = 9000
                                    # port number for watchdog service
                                    # (change requires restart)
wd_priority = 1
                                    # priority of this watchdog in leader election
                                    # (change requires restart)

wd_authkey = ''
                                    # Authentication key for watchdog communication
                                    # (change requires restart)

wd_ipc_socket_dir = '/tmp'
                                    # Unix domain socket path for watchdog IPC socket
                                    # The Debian package defaults to
                                    # /var/run/postgresql
                                    # (change requires restart)


# - Virtual IP control Setting -
# 激活虚拟VIP，vip在hosts里面设置解析，否则直接填写ip
delegate_IP = 'vip'
                                    # delegate IP address
                                    # If this is empty, virtual IP never bring up.
                                    # (change requires restart)
if_cmd_path = '/sbin'
                                    # path to the directory where if_up/down_cmd exists
                                    # If if_up/down_cmd starts with "/", if_cmd_path will be ignored.
                                    # (change requires restart)
#if_up_cmd = '/usr/bin/sudo /sbin/ip addr add $_IP_$/24 dev eth0 label eth0:0'
# 执行添加vip地址命令
if_up_cmd = '/sbin/ifconfig ens192:0 inet $_IP_$ netmask 255.255.254.0'
                                    # startup delegate IP command
                                    # (change requires restart)
#if_down_cmd = '/usr/bin/sudo /sbin/ip addr del $_IP_$/24 dev eth0'
# 执行删除vip地址命令
if_down_cmd = '/sbin/ifconfig ens192:0 down'
                                    # shutdown delegate IP command
                                    # (change requires restart)
arping_path = '/usr/sbin'
                                    # arping command path
                                    # If arping_cmd starts with "/", if_cmd_path will be ignored.
                                    # (change requires restart)
arping_cmd = '/usr/bin/sudo /usr/sbin/arping -U $_IP_$ -w 1 -I ens192'
                                    # 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)
wd_de_escalation_command = ''
                                    # Executes this command when master pgpool resigns from being master.
                                    # (change requires restart)

# - Watchdog consensus settings for failover -

failover_when_quorum_exists = on
                                    # Only perform backend node failover
                                    # when the watchdog cluster holds the quorum
                                    # (change requires restart)

failover_require_consensus = on
                                    # Perform failover when majority of Pgpool-II nodes
                                    # aggrees on the backend node status change
                                    # (change requires restart)

allow_multiple_failover_requests_from_node = off
                                    # A Pgpool-II node can cast multiple votes
                                    # for building the consensus on failover
                                    # (change requires restart)

enable_consensus_with_half_votes = off
                                    # apply majority rule for consensus and quorum computation
                                    # at 50% of votes in a cluster with even number of nodes.
                                    # when enabled the existence of quorum and consensus
                                    # on failover is resolved after receiving half of the
                                    # total votes in the cluster, otherwise both these
                                    # decisions require at least one more vote than
                                    # half of the total votes.
                                    # (change requires restart)

# - Lifecheck Setting -

# -- common --

wd_monitoring_interfaces_list = ''  # Comma separated list of interfaces names to monitor.
                                    # if any interface from the list is active the watchdog will
                                    # consider the network is fine
                                    # 'any' to enable monitoring on all interfaces except loopback
                                    # '' to disable monitoring
                                    # (change requires restart)


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

# -- heartbeat mode --
# 激活心跳侦测
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)
# 对端地址，与master节点相反
heartbeat_destination0 = 'test2'
                                    # 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)
# 执行侦测的网卡
heartbeat_device0 = 'ens192'
                                    # 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
                                    # Leaving it empty will make Pgpool-II to first look for the
                                    # Password in pool_passwd file before using the empty password
                                    # (change requires restart)

# - Other pgpool Connection Settings -
# 激活其他pgpool服务器节点连接信息

#other_pgpool_hostname0 = 'host0'
other_pgpool_hostname0 = 'test2'
                                    # Host name or IP address to connect to for other pgpool 0
                                    # (change requires restart)
# pgpool连接端口改为9999
other_pgpool_port0 = 9999
                                    # Port number for other pgpool 0
                                    # (change requires restart)
other_wd_port0 = 9000
                                    # Port number for other 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 = catalog
                                   # Temporary table check method. catalog, trace or none.
                                   # Default is catalog.

check_unlogged_table = on
                                   # If on, enable unlogged 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 unlogged tables
                                   # and you want to save access to primary/master, you could turn this off.
                                   # Default is on.
enable_shared_relcache = on
                                   # If on, relation cache stored in memory cache,
                                   # the cache is shared among child process.
                                   # Default is on.
                                   # (change requires restart)

relcache_query_target = master     # Target node to send relcache queries. Default is master (primary) node.
                                   # If load_balance_node is specified, queries will be sent to load balance node.
#------------------------------------------------------------------------------
# IN MEMORY QUERY MEMORY CACHE
#------------------------------------------------------------------------------
memory_cache_enabled = off
                                   # If on, use the memory cache functionality, off by default
                                   # (change requires restart)
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

配置文件里，故障处理配置的是failover_command = ‘/etc/pgpool-II-10/failover_stream.sh %H ‘，因此，需要在/opt/pgpool目录中写个failover_stream.sh脚本：

[postgres@master ~]$ cd /etc/pgpool-II-10
[postgres@pgpool~]$ touch failover_stream.sh
[postgres@pgpool~]$ vim failover_stream.sh

#! /bin/sh 
# Failover command for streaming replication. 
# Arguments: $1: new master hostname. 

new_master=$1
trigger_command="/usr/pgsql-10/bin/pg_ctl promote -D /pgdata"

# Prompte standby database. 
# 升级从数据库为主节点
/usr/bin/ssh -T $new_master $trigger_command

exit 0;

如果是其他用户创建的，需要赋予postgres可执行权限，例如

[root@opt ~]$ chown -R postgres.postgres /opt/pgpool
[root@opt ~]]$ chmod 777  /opt/pgpool/failover_stream.sh

3.6 启动集群

分别启动postgrsql

systemctl start postgresql-10.service

分别启动pgpool

systemctl start pgpool-II-10.service

启动pgpool后，查看集群节点状态:

[postgres@master ~]$ psql -h vip -p 9999
psql (9.6.1)
#提示输入密码：
Type "help" for help.

postgres=# show pool_nodes;
 node_id | hostname | port | status | lb_weight |  role   | select_cnt | load_balance_node | replication_delay 
---------+----------+------+--------+-----------+---------+------------+-------------------+-------------------
 0       | master   | 5432 | up     | 0.500000  | primary | 0             | false  | 0
 1       | slave     | 5432 | up     | 0.500000  | standby | 0             |  true  | 0
(2 rows)

#在slave上节点也是psql -h vip -p 9999，双pgpool使用虚拟ip，做到高可用。

发现当前主备节点都是正常的up状态。