基于上次的postgresql单机安装，部署postgresql异步流复制
环境准备：
| IP |
配置 |
角色 |
| 192.168.56.117 | 1C/2G/20GB centos7 | 主 |
| 192.168.56.118 | 1C/2G/20GB centos7 | 从 |
主库执行：
创建用户：
groupadd postgresuseradd -g postgres postgres
创建目录：
mkdir -p /postgresql/datachown -R postgres.postgres /postgresql/datamkdir -p /postgresql/archivechown -R postgres.postgres /postgresql/archive
初始化主库：
initdb -D /postgresql/data
修改主库配置：
vim /postgresql/data/postgresql.conf
listen_addresses = '*'port = 5432max_wal_senders = 10wal_level = replicaarchive_mode = onarchive_command = 'cp %p /postgresql/archive/%f'hot_standby = on
vim /data/pg/pg_hba.conf
在最后添加一行
host replication repl 192.168.56.0/24 md5
重启主库：
su - postgrespg_ctl -D /postgresql/data/ restart
创建复制用户：
psqlCREATE USER repl replication LOGIN CONNECTION LIMIT 5 ENCRYPTED PASSWORD '123456';
备库执行：
创建用户：
groupadd postgresuseradd -g postgres postgres
创建数据目录：
mkdir -p /postgresql/datachown -R postgres.postgres /postgresql/datamkdir -p /postgresql/archivechown -R postgres.postgres /postgresql/archive
创建基于主库的基础备份：
su - postgrespg_basebackup -h 192.168.56.117 -U repl -W -p 5432 -Fp -Xs -v -P -D /postgresql/data -l backup_label -R
[postgres@localhost data]$ pg_basebackup -h 192.168.56.117 -U repl -W -p 5432 -Fp -Xs -v -P -D /postgresql/data -l backup_label -RPassword: pg_basebackup: initiating base backup, waiting for checkpoint to completepg_basebackup: checkpoint completedpg_basebackup: write-ahead log start point: 0/6000028 on timeline 1pg_basebackup: starting background WAL receiverpg_basebackup: created temporary replication slot "pg_basebackup_2964"32554/32554 kB (100%), 1/1 tablespace pg_basebackup: write-ahead log end point: 0/6000100pg_basebackup: waiting for background process to finish streaming ...pg_basebackup: syncing data to disk ...pg_basebackup: base backup completed
不同于postgresql11版本及之前，postgresql12在建立流复制方面有所改动：
recovery.conf is no longer used, and the server will not start if the file exists. recovery.signal and standby.signal are now used to switch into non-primary mode. trigger_file has been renamed to promote_trigger_file. The standby_mode setting has been removed.
大致包含如下改动：
recover.conf不再支持，其中的参数合并至postgresql.conf，如该文件存在，则数据库启动失败
不再支持standby_mode参数
增加recover.signal文件，表示数据库处于recover模式
增加standby.signal文件，表示数据库处于standby模式
trigger_file参数重命名为promote_trigger_file
在基础备份pb_basebackup中指定-R则会在数据目录生成standby.signal
在postgresql.auto.conf中，也生成了primary_conninfo参数配置
[postgres@localhost data]$ cat postgresql.auto.conf # Do not edit this file manually!# It will be overwritten by the ALTER SYSTEM command.primary_conninfo = 'user=repl password=123456 host=192.168.56.117 port=5432 sslmode=disable sslcompression=0 gssencmode=disable krbsrvname=postgres target_session_attrs=any'
启动备库：
pg_ctl -D /data/pg start
验证流复制状态：
主库执行：
select * from pg_stat_replication;\x
查看流复制状态：
postgres=# select * from pg_stat_replication;\x-[ RECORD 1 ]----+------------------------------pid | 3048usesysid | 16384usename | replapplication_name | walreceiverclient_addr | 192.168.56.118client_hostname |client_port | 60894backend_start | 2020-09-04 10:37:11.915897+08backend_xmin |state | streamingsent_lsn | 0/7000148write_lsn | 0/7000148flush_lsn | 0/7000148replay_lsn | 0/7000148write_lag | 00:00:00.030901flush_lag | 00:00:00.032029replay_lag | 00:00:00.032136sync_priority | 0sync_state | asyncreply_time | 2020-09-04 10:37:11.939726+08Expanded display is off.