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1, postgresql移步同步 and 主备切换
2, postgresql 同步 and 主备切换
3, archive 数据同步
参考: <<从小工到专家>>
postgres hot_standby 主从配置部署: (hot_standy)
版本: postgresql 9.6.2
Centos 6.8 x86 64bit
目录: /usr/local/pgsql* --安装目录
/data/postgres/posdb --数据目录
配置文件: pg_hba.conf 网管控制(配置参数)
postgres.conf 数据库参数配置文件
recovery.conf 备库需手动创建的 配置同步参数文件
主库: 10.0.1.82 端口: 5438
备库: 192.168.41.212 端口: 5438
流复制: (原理详解)
9.0开始提供的一种新的传递WAL 日志的方式, 只要primary 数据库 一产生日志, 就会传递到standby 数据库. (1,异步,2,同步) 两种方式.
(9.2 增加了级联复制功能
),
9.0之前, 主从需第三方同步拷贝
数据同步方式时
: 在primary 提交事务时, 一定会等到WAL 日志传递到standby 后才返回, 这样可以得到standby 数据完全和 primary 数据库同步. 没有一点落后.(自动切换,可以达到零丢失)
数据异步同步方式
: Primary 提交事务后,不必等日志传递到standby 就即可返回. 所以standby 数据库通常 比primary 落后很少.
standby 运行原理:
postgresql 数据库异常中止后, 数据库重启,,会重放停机前最后一个checkpoint 点之后的 WAL 日志. 再把数据库恢复到停机时的状态.
创建standby 的过程分为俩大步骤:
a, 生成一个基础备份 , 通过pg_start_backup('db_name'), pg_stop_backup();
select pg_start_backup('target')
--Ps: 可以使用pg_basebackup 来 完成基础备份的步骤.
b, 拷贝备份过程中的所有WAL 日志文件.
pg_basebackup 命令简介:
这个工具会把整个数据库实例都拷贝出来, 而
不只是
把实例中的部分(某个数据库或某张表) 单独备份出来. 该工具需要配置 pg_hba.conf 参数文件
参数:
-D
directory 或 --pgdata=directory 指定把备份写到那个目录.(如果目录不存在,会自动创建)
-F
format 或 --format=format : 指定输出的格式 目前支持两种格式:
a, 原样输出, 这种情况下 format 指定为" p" 或"plain";
b, tar格式, 这种相当于把输出的备份文件打包一个tar文件中, 指定为"t" 或"tar"
-x
或 --xlog : 备份时会把备份中产生的xlog 文件也自动备份出来. 这样在数据库恢复时,应用这些xlog 文件,把数据库推到一个一致点. 设置这个选项需要设置
wal_keep_segments 参数(以抱枕在备份过程中,需要的WAL日志文件不会被覆盖
). 与选项 -X fetch 完全一样.
-X
method 或
xlog-method=method: 可以取的值为"f" , "fetch", "s" ,"stream"
, 当为f时,与fetch意义相同, 与-x 参数一样.
当为"s", stream 表示意思也相同,表示备份开始后,启动另一个流复制从主库接收WAL日志
.(这种方式避免了,使用-X f时, 主库上的WAL日志有可能被覆盖从而导致失败的问题.), 使用这种连接,主库需要配置 max_wal_senders 至少需要大于2
-z 或 --gzip, 仅能与tar 输出模式配合使用. 表示tar 备份是经过gzip 压缩的. 生成tar.gz 备份包.
-Z level 或 --compress=level, 指定gzip 压缩级别(1-9) , 级别越高,耗CPU 越厉害.
-c fast | spread 或 --checkpoint=fast | spread : 设置checkpoint 的模式是fast还是spread .
-l label 或 --label=label , 指定备份的一个标示. 备份的标识是一个任意字符串,便于今后维护识别.
-P 或 --progress , 允许在备份过程中实时打印备份进度.
-v 或--verbose , 详细模式,在使用-P 参数后,会打印出正在备份的具体的信息.
-V 或 --version, 打印pg_basebackup 的版本后,退出.
----------------------------
-h host 或 --host =host , 执行连接数据库的IP地址或主机名
-p port 或 --port=port 指定连接端口
-s interval 或 --status-interval = interval: 指定向服务器周期反馈状态的秒数, 如果服务器配置了 流复制的超时,在使用--xlog=stream 选项时, 这需要设置这个参数. 默认为10s, 如果设置为0 , 表示不向服务器反馈状态.
eg: pg_basebackup -F p --progress -D /data/postgresql/postdb -h 10.0.1.82 -p 5438 -U replica --password (基础备份)
############# 我是华丽分界线 ################
安装postgresql :
groupadd -g 1200 postgres
useradd -m -u 1100 -g postgres postgres
mkdir -pv /data/PostgreSQL/{postgresdb,postgreslog}
gunzip postgresql-9.6.2-3-linux-x64-binaries.tar.gz
tar -xvf postgresql-9.6.2-3-linux-x64-binaries.tar -C /usr/local/
初始化postgressql 数据库:
cd /usr/local/pgsql-9.6.2/bin
./initdb -E utf8 -D /data/PostgreSQL/postgresdb
主库: postgres.conf 配置 (4GB-Memory)
## authentic setting ##
port = 5438
max_connections = 500
unix_socket_directories = '/tmp'
listen_addresses = '*'
superuser_reserved_connections = 5
#uthentication_timeout = 60
deadlock_timeout =2000
max_locks_per_transaction = 64
## base setting ##
datestyle = 'iso, mdy'
timezone = 'PRC'
lc_messages = 'en_US.UTF-8'
lc_monetary = 'en_US.UTF-8'
lc_numeric = 'en_US.UTF-8'
lc_time = 'en_US.UTF-8'
default_text_search_config = 'pg_catalog.english'
## log setting ##
logging_collector = on
log_destination = 'csvlog'
log_directory = '/data/postgres/poslog'
# -- every day on logs -- #
log_filename = 'pglog5438-%Y-%m-%d_%H%M%S.log'
log_file_mode = 0600
log_connections = on
log_disconnections = off
log_checkpoints = on
log_rotation_age = 1d
log_rotation_size = 200MB
log_truncate_on_rotation = off
log_timezone = 'PRC'
log_lock_waits = on
log_min_duration_statement = 3s
log_lock_waits = on
log_min_messages = info
log_min_error_statement = info
## memory setting ##
shared_buffers = 512MB
temp_buffers = 16MB
work_mem = 32MB
effective_cache_size = 2GB
maintenance_work_mem = 128MB
#max_stack_depth = 2MB
dynamic_shared_memory_type = posix
## WAL setting ##
fsync = on
synchronous_commit = on
wal_sync_method = fdatasync
# -- yixia is defaults -- #
full_page_writes = on
wal_buffers = 16MB
wal_writer_delay = 200ms
commit_delay = 0
commit_siblings = 5
#wal_level = archive
#wal_level = hot_standby
archive_mode = on
archive_command = 'cp %p /data/postgres/pos_archive/%f'
## statistic setting ##
track_activities = on
log_statement_stats = on
# log_parser_stats =
# log_planner_stats =
# log_executor_stats =
autovacuum = on
track_counts = on
## async standby setting ##
max_wal_senders = 5
wal_level = hot_standby
#listen_addresses = '*'
wal_keep_segments = 10240
wal_sender_timeout = 120s
## 初次需要修改参数 ##
listener_addresses = '*' --可以是IP, 也可以是 ' * ' 替代.
wal_level = hot_standby --热备模式开启
max_wal_sender = 5 --可以并行设置几个流复制连接进程.( 几个从,设置几个)
wal_keep_segments = 10240 #重要配置 流复制
wal_send_timeout = 60s --可防止逻辑错误,延缓同步时间.
max_connections = 512 --standby此参数设置最好比primary 设置的要大.
archive_mode = on --允许归档
archive_command = 'cp % /data/postgreslog/archivelog/%f' --归档路径
关于wal 日志归档描述:
--以上是主库设置.
编辑环境变量:
[[email protected] ~]$ cat .bash_profile
# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
# User specific environment and startup programs
PATH=$PATH:$HOME/bin
export PATH
export DATADIR=/data/postgres/posdb
export BASEDIR=/usr/local/pgsql-9.6.2
export PATH=$BASEDIR/bin:$PATH:$HOME/bin:$PATH
编辑 pg_hba.conf 配置参数文件:
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all trust
# IPv4 local connections:
host all all 127.0.0.1/32 trust
# IPv6 local connections:
host all all ::1/128 trust
host all all 0.0.0.0/0 trust #因本地测试环境,我全放开
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local replication postgres trust
#host replication postgres 127.0.0.1/32 trust
host replication postgres ::1/128 trust
host replication replica 192.168.41.0/24 trust #流复制IP target 端 (网段)
host replication replica 10.0.1.0/24 trust #流复制IP target 端 (网段)
--replication 表示支持流复制. 使用的是replica 用户
启动主库, postgresql 数据库
a, 通过
/usr/local/pgsql-9.6.2/bin/postgres -D /data/postgres/posdb
b, pg_ctl start -D /data/postgres/posdb
检测 启动进程
[[email protected] posdb]# lsof -i:5438
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
postgres 11734 postgres 3u IPv4 19736071 0t0 TCP *:5438 (LISTEN)
postgres 11734 postgres 4u IPv6 19736072 0t0 TCP *:5438 (LISTEN)
postgres 11960 postgres 10u IPv4 19738713 0t0 TCP limin-test.novalocal:5438->192.168.41.212:56398 (ESTABLISHED)
# 备库设置:
a, 如果为开始的初始话数据库, 不需要删除 /data/目录下的文件. 如果不是,最好删除.
b, 备份复制: pg_basebackup -F p --progress -D /data/postgresql/postdb -h 10.0.1.82 -p 5438 -U replica --password
c, 手动创建recovery.conf 配置文件:
[postgres@newmachine postdb]$ cat recovery.conf
standby_mode = on
trigger_file = '/data/postgresql/postlog/trigger.kenyou'
recovery_target_timeline = 'latest'
restore_command = 'cp %p /data/postgresql/postdb/%f'
primary_conninfo = 'host=10.0.1.82 port=5438 user=replica password=replica'
d, 根据主库的postgresql.conf 配置文件 修改参数配置:
1, listen_addresses = '* '
2, wal_level = hot_standby
3, max_connections = xxx, # 一般比主库大一些.
4,hot_standby = on
5, max_standby_streaming_delay = 30s
6. wal_receiver_status_interval = 10s
7, hot_standby_feedback = on # 如果有错误的数据复制,是否向 主进行范例.
### 备库 postgresql.conf 配置文件 ####
[postgres@newmachine postdb]$ cat recovery.conf
standby_mode = on
trigger_file = '/data/postgresql/postlog/trigger.kenyou'
recovery_target_timeline = 'latest'
restore_command = 'cp %p /data/postgresql/postdb/%f'
primary_conninfo = 'host=10.0.1.82 port=5438 user=replica password=replica'
[postgres@newmachine postdb]$ cat postgresql.conf
## authentic setting ##
port = 5438
max_connections = 550
unix_socket_directories = '/tmp'
listen_addresses = '*'
superuser_reserved_connections = 5
#uthentication_timeout = 60
deadlock_timeout =2000
max_locks_per_transaction = 64
## base setting ##
datestyle = 'iso, mdy'
timezone = 'PRC'
lc_messages = 'en_US.UTF-8'
lc_monetary = 'en_US.UTF-8'
lc_numeric = 'en_US.UTF-8'
lc_time = 'en_US.UTF-8'
default_text_search_config = 'pg_catalog.english'
## log setting ##
logging_collector = on
log_destination = 'csvlog'
log_directory = '/data/postgresql/postlog'
# -- every day on logs -- #
log_filename = 'pglog5438-%Y-%m-%d_%H%M%S.log'
log_file_mode = 0600
log_connections = on
log_disconnections = off
log_checkpoints = on
log_rotation_age = 1d
log_rotation_size = 200MB
log_truncate_on_rotation = off
log_timezone = 'PRC'
log_lock_waits = on
log_min_duration_statement = 3s
log_lock_waits = on
log_min_messages = info
log_min_error_statement = info
## memory setting ##
shared_buffers = 512MB
temp_buffers = 16MB
work_mem = 32MB
effective_cache_size = 2GB
maintenance_work_mem = 128MB
#max_stack_depth = 2MB
dynamic_shared_memory_type = posix
## WAL setting ##
fsync = on
synchronous_commit = on
wal_sync_method = fdatasync
# -- yixia is defaults -- #
full_page_writes = on
wal_buffers = 16MB
wal_writer_delay = 200ms
commit_delay = 0
commit_siblings = 5
#wal_level = archive
#wal_level = hot_standby
archive_mode = on
archive_command = 'cp %p /data/postgresql/postdb/%f'
#restore_command = 'cp %p /data/postgresql/postdb/%f'
## statistic setting ##
track_activities = on
log_statement_stats = on
autovacuum = on
track_counts = on
## async standby setting ##
max_wal_senders = 5
wal_level = hot_standby
#listen_addresses = '*'
wal_keep_segments = 10240
wal_sender_timeout = 120s
hot_standby = on
hot_standby_feedback = on
max_standby_streaming_delay = 20s
wal_receiver_status_interval = 1s
## 启动备库:
pg_ctl start -D /data.....
##检测主从 复制状态: (主库上查看)
select client_addr, sync_state from pg_stat_replication;
postgres=# select client_addr, sync_state from pg_stat_replication;
client_addr | sync_state
----------------+------------
192.168.41.212 | async
(1 row)
postgres=#
postgres=# select * from pg_stat_replication;
pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | ba
ckend_start | backend_xmin | state | sent_location | write_location | flush_location | replay_lo
cation | sync_priority | sync_state
-------+----------+---------+------------------+----------------+-----------------+-------------+-----------
--------------------+--------------+-----------+---------------+----------------+----------------+----------
-------+---------------+------------
11960 | 16568 | replica | walreceiver | 192.168.41.212 | | 56398 | 2017-08-16
17:37:45.876011+08 | 1761 | streaming | 0/801DB70 | 0/801DB70 | 0/801DB70 | 0/801DB70
| 0 | async
(1 row)
## 数据 ddl, dml 操作测试:
##standby 只读, 所以任何操作, 都会告警失败:
postgres=# drop database martinli;
ERROR: cannot execute DROP DATABASE in a read-only transaction
[postgres@limin-test ~]$ netstat -lntup|grep 5438 && ps -ef|grep postmaster
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 0.0.0.0:5438 0.0.0.0:* LISTEN 11734/postgres
tcp 0 0 :::5438 :::* LISTEN 11734/postgres
主库 sender :
[postgres@limin-test ~]$ ps -ef |grep postgres |grep sender
postgres 11960 11734 0 Aug16 ? 00:00:19 postgres: wal
sender process replica 192.168.41.212(56398) streaming 0/801F168
postgres 24621 20934 0 16:56 pts/0 00:00:00 grep sender
备库 recover :
[postgres@newmachine postdb]$ ps -ef |grep postgres |grep recover
postgres 27798 27796 0 Aug16 ? 00:00:00 postgres: startup process
recovering 000000010000000000000008
postgres 28948 28759 0 08:53 pts/4 00:00:00 grep recover
----------------- 异步 同步部署完成 ------------
异步postgresql 主备切换:
1, 停止主库:
[postgres@limin-test ~]$ pg_ctl stop -D /data/postgres/posdb/
waiting for server to shut down....... done
server stopped
------
主库 log 日志:
2017-08-17 17:00:46.522 CST,,,11734,,59940c60.2dd6,5,,2017-08-16 17:12:00 CST,,0,LOG,00000,
"database system is shut down",,,,,,,,,""
--------
此时备库的日志:
",,,,,,,,,""
2017-08-17 08:58:19.789 CST,,,28962,,5994ea2b.7122,1,,2017-08-17 08:58:19 CST,,0,FATAL,XX000,"
could not connect to the primary server: could not connect to server: Connection refused
Is the server running on host ""10.0.1.82"" and accepting
TCP/IP connections on port 5438?
",,,,,,,,,""
----------
2, 查看备库的 recovery.conf 参数文件， 在对应的目录下创建 trigger 文件.
[postgres@newmachine postdb]$ cat recovery.conf
standby_mode = on
trigger_file = '/data/postgresql/postlog/trigger.kenyou'
recovery_target_timeline = 'latest'
restore_command = 'cp %p /data/postgresql/postdb/%f'
primary_conninfo = 'host=10.0.1.82 port=5438 user=replica password=replica'
cd
/data/postgresql/postlog/
touch trigger.kenyou # 这一步很重要. 创建后, ll 查看,并没有什么, 但是, 日志及recovery.conf 文件变了:
--------------- 数据状态查看------
通过pg_controldata :
未创建 (
touch trigger.kenyou
) 触发文件之前的 状态信息:
备库:
[postgres@newmachine postlog]$ pg_controldata -D /data/postgresql/postdb/
pg_control version number: 960
Catalog version number: 201608131
Database system identifier: 6410192200887248642
Database cluster state: in archive recovery # 提示恢复状态.
pg_control last modified: Thu 17 Aug 2017 08:59:15 AM CST
Latest checkpoint location: 0/9000028
Prior checkpoint location: 0/801F1A0
Latest checkpoint's REDO location: 0/9000028
Latest checkpoint's REDO WAL file: 000000010000000000000009
Latest checkpoint's TimeLineID: 1
Latest checkpoint's PrevTimeLineID: 1
Latest checkpoint's full_page_writes: on
Latest checkpoint's NextXID: 0:1761
Latest checkpoint's NextOID: 16571
Latest checkpoint's NextMultiXactId: 1
Latest checkpoint's NextMultiOffset: 0
Latest checkpoint's oldestXID: 1668
Latest checkpoint's oldestXID's DB: 1
Latest checkpoint's oldestActiveXID: 0
Latest checkpoint's oldestMultiXid: 1
Latest checkpoint's oldestMulti's DB: 1
Latest checkpoint's oldestCommitTsXid:0
Latest checkpoint's newestCommitTsXid:0
Time of latest checkpoint: Thu 17 Aug 2017 05:00:44 PM CST
Fake LSN counter for unlogged rels: 0/1
Minimum recovery ending location: 0/9000098
Min recovery ending loc's timeline: 1
Backup start location: 0/0
Backup end location: 0/0
End-of-backup record required: no
wal_level setting: replica
wal_log_hints setting: off
max_connections setting: 500
max_worker_processes setting: 8
max_prepared_xacts setting: 0
max_locks_per_xact setting: 64
track_commit_timestamp setting: off
Maximum data alignment: 8
Database block size: 8192
Blocks per segment of large relation: 131072
WAL block size: 8192
Bytes per WAL segment: 16777216
创建 (
touch trigger.kenyou
) 触发文件之后的 状态信息:
备库:
[postgres@newmachine postlog]$ pg_controldata -D /data/postgresql/postdb/
pg_control version number: 960
Catalog version number: 201608131
Database system identifier: 6410192200887248642
Database cluster state: in production # 变法了.
pg_control last modified: Thu 17 Aug 2017 09:10:30 AM CST
Latest checkpoint location: 0/9000138
Prior checkpoint location: 0/9000028
Latest checkpoint's REDO location: 0/9000100
Latest checkpoint's REDO WAL file: 000000020000000000000009
Latest checkpoint's TimeLineID: 2
Latest checkpoint's PrevTimeLineID: 2
Latest checkpoint's full_page_writes: on
Latest checkpoint's NextXID: 0:1761
Latest checkpoint's NextOID: 16571
Latest checkpoint's NextMultiXactId: 1
Latest checkpoint's NextMultiOffset: 0
Latest checkpoint's oldestXID: 1668
Latest checkpoint's oldestXID's DB: 1
Latest checkpoint's oldestActiveXID: 1761
Latest checkpoint's oldestMultiXid: 1
Latest checkpoint's oldestMulti's DB: 1
Latest checkpoint's oldestCommitTsXid:0
Latest checkpoint's newestCommitTsXid:0
Time of latest checkpoint: Thu 17 Aug 2017 09:10:30 AM CST
Fake LSN counter for unlogged rels: 0/1
Minimum recovery ending location: 0/0
Min recovery ending loc's timeline: 0
Backup start location: 0/0
Backup end location: 0/0
End-of-backup record required: no
wal_level setting: replica
wal_log_hints setting: off
max_connections setting: 550
max_worker_processes setting: 8
max_prepared_xacts setting: 0
max_locks_per_xact setting: 64
track_commit_timestamp setting: off
Maximum data alignment: 8
Database block size: 8192
Blocks per segment of large relation: 131072
WAL block size: 8192
Bytes per WAL segment: 16777216
Maximum length of identifiers: 64
Maximum columns in an index: 32
Maximum size of a TOAST chunk: 1996
Size of a large-object chunk: 2048
Date/time type storage: 64-bit integers
Float4 argument passing: by value
Float8 argument passing: by value
Data page checksum version: 0
同时,恢复配置文件由
recovery.conf 变为了 recovery.done
[postgres@newmachine postdb]$
cat recovery.done
standby_mode = on
trigger_file = '/data/postgresql/postlog/trigger.kenyou'
recovery_target_timeline = 'latest'
restore_command = 'cp %p /data/postgresql/postdb/%f'
primary_conninfo = 'host=10.0.1.82 port=5438 user=replica password=replica'
------log 日志状态 ------
",,,,,,,,,""
2017-08-17 09:10:25.520 CST,,,29138,,5994ed01.71d2,1,,2017-08-17 09:10:25 CST,,0,FATAL,XX000,"could not connect to the primary server: could not connect to server: Connection refused
Is the server running on host ""10.0.1.82"" and accepting
TCP/IP connections on port 5438?
",,,,,,,,,"" ### 这里是未创建 trigger 之前的提示.
2017-08-17 09:10:30.522 CST,,,27798,,5993a108.6c96,6,,2017-08-16 09:34:00
CST,1/0,0,LOG,00000,"trigger file found: /data/postgresql/postlog/trigger.kenyou",,,,,,,,,""
## 这里找到了一个trigger 文件, (touch trigger.kenyou 后)
2017-08-17 09:10:30.522 CST,,,27798,,5993a108.6c96,7,,2017-08-16 09:34:00 CST,1/0,0,LOG,00000,"redo done at 0/9000028",,,,,,,,,""
2017-08-17 09:10:30.522 CST,,,27798,,5993a108.6c96,8,,2017-08-16 09:34:00
CST,1/0,0,LOG,00000,"last completed transaction was at log time 2017-08-16 17:57:07.604087+08",,,,,,,,,""
2017-08-17 09:10:30.587 CST,,,27798,,5993a108.6c96,9,,2017-08-16 09:34:00 CST,1/0,0,LOG,00000,"selected new timeline ID: 2",,,,,,,,,""
2017-08-17 09:10:30.788 CST,,,27798,,5993a108.6c96,10,,2017-08-16 09:34:00 CST,1/0,0,LOG,00000,"archive recovery complete",,,,,,,,,""
2017-08-17 09:10:30.844 CST,,,27798,,5993a108.6c96,11,,2017-08-16 09:34:00 CST,1/0,0,LOG,00000,"MultiXact member wraparound protections are now enabled",,,,,,,,,""
2017-08-17 09:10:30.868 CST,,,27800,,5993a109.6c98,844,,2017-08-16 09:34:01
CST,,0,LOG,00000,"checkpoint starting: force",,,,,,,,,""
2017-08-17 09:10:30.870 CST,,,27796,,5993a108.6c94,3,,2017-08-16 09:34:00 CST,,0,LOG,00000,"database system is ready to accept connections",,,,,,,,,""
2017-08-17 09:10:30.870 CST,,,29142,,5994ed06.71d6,1,,2017-08-17 09:10:30 CST,,0,LOG,00000,"autovacuum launcher started",,,,,,,,,""
2017-08-17 09:10:30.940 CST,,,27800,,5993a109.6c98,845,,2017-08-16 09:34:01 CST,,0,LOG,00000,"checkpoint complete: wrote 0 buffers (0.0%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=0.001 s, sync=0.000 s, total=0.072 s; sync files=0, longest=0.000 s, average=0.000 s; distance=0 kB, estimate=14633 kB",,,,,,,,,""
2017-08-17 09:15:30.946 CST,,,27800,,5993a109.6c98,846,,2017-08-16 09:34:01 CST,,0,LOG,00000,"checkpoint starting: time",,,,,,,,,""
2017-08-17 09:15:31.091 CST,,,27800,,5993a109.6c98,847,,2017-08-16 09:34:01
CST,,0,LOG,00000,"checkpoint complete: wrote 1 buffers (0.0%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=0.102 s, sync=0.018 s, total=0.144 s; sync files=1, longest=0.018 s, average=0.018 s; distance=0 kB, estimate=13170 kB",,,,,,,,,""
--------------
主库:
[[email protected] posdb]$ pg_controldata -D /data/postgres/posdb/
pg_control version number: 960
Catalog version number: 201608131
Database system identifier: 6410192200887248642
Database cluster state: shut down ## 因关闭了, 所以主库的状态不会改变.
pg_control last modified: Thu 17 Aug 2017 05:00:46 PM CST
Latest checkpoint location: 0/9000028
Prior checkpoint location: 0/801F1A0
Latest checkpoint's REDO location: 0/9000028
Latest checkpoint's REDO WAL file: 000000010000000000000009
Latest checkpoint's TimeLineID: 1
Latest checkpoint's PrevTimeLineID: 1
Latest checkpoint's full_page_writes: on
Latest checkpoint's NextXID: 0:1761
Latest checkpoint's NextOID: 16571
Latest checkpoint's NextMultiXactId: 1
Latest checkpoint's NextMultiOffset: 0
Latest checkpoint's oldestXID: 1668
Latest checkpoint's oldestXID's DB: 1
Latest checkpoint's oldestActiveXID: 0
Latest checkpoint's oldestMultiXid: 1
Latest checkpoint's oldestMulti's DB: 1
Latest checkpoint's oldestCommitTsXid:0
Latest checkpoint's newestCommitTsXid:0
Time of latest checkpoint: Thu 17 Aug 2017 05:00:44 PM CST
Fake LSN counter for unlogged rels: 0/1
Minimum recovery ending location: 0/0
Min recovery ending loc's timeline: 0
Backup start location: 0/0
Backup end location: 0/0
End-of-backup record required: no
wal_level setting: replica
wal_log_hints setting: off
max_connections setting: 500
max_worker_processes setting: 8
max_prepared_xacts setting: 0
max_locks_per_xact setting: 64
track_commit_timestamp setting: off
Maximum data alignment: 8
Database block size: 8192
Blocks per segment of large relation: 131072
WAL block size: 8192
Bytes per WAL segment: 16777216
Maximum length of identifiers: 64
Maximum columns in an index: 32
Maximum size of a TOAST chunk: 1996
Size of a large-object chunk: 2048
Date/time type storage: 64-bit integers
Float4 argument passing: by value
Float8 argument passing: by value
Data page checksum version: 0
新主库监听检测:
[postgres@newmachine postlog]$ ps -ef |grep pos |grep sender
postgres 29186 27796 0 09:27 ? 00:00:00 postgres: wal
sender process replica 10.0.1.82(16143) streaming 0/9000480
postgres 29200 28408 0 09:30 pts/3 00:00:00 grep sender
3, 把 原备库的 recover.conf 文件 拷贝至原主库,修改对应信息:
[postgres@limin-test posdb]$ cat recovery.conf
standby_mode = on
trigger_file = '/data/postgres/posdb/trigger.kenyou' ## 这里创建需要注意,与原主对应.
recovery_target_timeline = 'latest'
restore_command = 'cp %p /data/postgres/poslog/%f'
#primary_conninfo = 'host=10.0.1.82 port=5438 user=replica password=replica'
primary_conninfo = 'host=192.168.41.212 port=5438 user=replica password=replica'
4, 启动原主库 (现在的备库)
pg_ctl start -D /data/postgres/posdb/
---------------
[[email protected] posdb]$ ps -ef |grep pos |grep recover
postgres 24823 24821 0 17:31 ? 00:00:00 postgres: startup process
recovering 000000020000000000000009
postgres 24834 21610 0 17:31 pts/2 00:00:00 grep recover
--状态检测(新备库)
[postgres@limin-test posdb]$ pg_controldata -D /data/postgres/posdb/
pg_control version number: 960
Catalog version number: 201608131
Database system identifier: 6410192200887248642
Database cluster state: in archive recovery
pg_control last modified: Thu 17 Aug 2017 05:29:05 PM CST
Latest checkpoint location: 0/9000028
Prior checkpoint location: 0/9000028
Latest checkpoint's REDO location: 0/9000028
Latest checkpoint's REDO WAL file: 000000010000000000000009
Latest checkpoint's TimeLineID: 1
Latest checkpoint's PrevTimeLineID: 1
Latest checkpoint's full_page_writes: on
Latest checkpoint's NextXID: 0:1761
Latest checkpoint's NextOID: 16571
验证: 在新主库(原主库上)
martinli=# select * from pg_stat_replication
martinli-# ;
pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | b
ackend_xmin | state | sent_location | write_location | flush_location | replay_location | sync_priority | sync_state
-------+----------+---------+------------------+-------------+-----------------+-------------+-------------------------------+--
------------+-----------+---------------+----------------+----------------+-----------------+---------------+------------
29278 | 16568 | replica | walreceiver | 10.0.1.82 | | 17444 | 2017-08-17 09:51:12.822522+08 |
1762 | streaming | 0/90164E0 | 0/90164E0 | 0/90164E0 | 0/90164E0 | 0 | async
(1 row)
martinli=# select client_addr,sync_state from pg_stat_replication ;
client_addr | sync_state
-------------+------------
10.0.1.82 | async
(1 row)
# 数据 dml ,ddl 操作测试: .此处省略 N 颗 字........
# 新备库 做 ddl, dml 操作, 查看 是否报错
martinli=# \dt test
List of relations
Schema | Name | Type | Owner
--------+------+-------+----------
public | test | table | postgres
(1 row)
martinli=# drop table test;
ERROR: cannot execute DROP TABLE in a read-only transaction
-------------- 我是华丽分割线 --------------END ----------
################## 参考 ############
原从库操作（原主库宕机情况下将其作为主库操作）：
在之前备机上的recovery.conf中配置trigger_file = ‘/data/pgdata/pg_stand_by/trigger.unl’
touch /data/pgdata/pg_stand_by/trigger.unl
修改 pg_hba.conf：
增加
host replication replica 172.18.18.99/32 md5
host replication replica 172.18.18.100/32 md5
重启从库: /usr/pgsql9.3.4/bin/pg_ctl restart -D /data/pgdata/pg_stand_by
查看是否切换成功：/usr/pgsql9.3.4/bin/pg_controldata /data/pgdata/pg_stand_by -》Database cluster state: in production 表示是主库
recovery.conf文件名字变成了recovery.done
3》原主库操作（恢复原主库为从库）：
cp /usr/pgsql9.3.4/share/recovery.conf.sample /data/pgdata/pg_primary/recovery.conf
修改recovery.conf：
recovery_target_timeline = ‘latest’
standby_mode = on
primary_conninfo = ‘host=172.18.18.101 port=3121 user=replica password=replica’
修改postgresql.conf文件：
hot_standby = on
启动原主库（当前从库）：/usr/pgsql9.3.4/bin/pg_ctl start -D /data/pgdata/pg_primary
4》修改100机器从库对应的主库信息：
修改recovery.conf ：
primary_conninfo = ‘host=172.18.18.101 port=3121 user=replica password=replica’
重启从库：/usr/pgsql9.3.4/bin/pg_ctl restart -D /data/pgdata/pg_stand_by -m fast
5》检查主从是否切换成功：
在新的主库上执行：
postgres=# select * from pg_stat_replication;
##################