前言
PostgreSQL 12 的一个重要变化是 recovery.conf 配置文件中的参数合并到 postgresql.conf,recovery.conf 不再使用 ;
参见:https://www.postgresql.org/docs/release/12.0/
Move recovery.conf settings into postgresql.conf (Masao Fujii, Simon Riggs, Abhijit Menon-Sen, Sergei Kornilov)
recovery.conf is no longer used, and the server will not start if that file exists.
recovery.signal and standby.signal files are now used to switch into non-primary mode.
The trigger_file setting has been renamed to promote_trigger_file. The standby_mode setting has been removed.
recovery.conf 配置文件此文件中的参数合并到 postgresql.conf
- recovery.conf 配置文件不再支持,若 recovery.conf 存在,数据库无法启动
- 新增 recovery.signal 标识文件和standby.signal 标识文件用于切换主从模式; recovery.signal表示数据库处于 recovery 模式
- trigger_file 参数更名为 promote_trigger_file
- standby_mode 参数不再支持
一、主从配置
角色 | 主机名 | IP |
主节点 | pg-master | 192.168.1.10 |
从节点 | pg-slave | 192.168.1.11 |
1.安装数据库服务
安装repos库
pg-master|pg-slave # yum install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
安装postgresql-server
pg-master|pg-slave # yum install postgresql12-server
在主节点初始化数据库
pg-master # /usr/pgsql-12/bin/postgresql-12-setup initdb
注: 从节点不需要初始化数据库
2. 主数据库配置
1. 修改主配置文件postgresql.conf
listen_addresses = '*'
port = 5432
shared_buffers = 4GB
wal_level = replica
fsync = on
max_wal_size = 1GB
min_wal_size = 80MB
archive_mode = on
archive_command = 'cp %p /var/lib/pgsql/12/archive_log/%f'
max_wal_senders = 5
wal_keep_segments = 0
wal_sender_timeout = 60s
max_replication_slots = 10
wal_level 确定将多少信息写入WAL,默认值是replica。
replica 将写入足够的数据以支持WAL归档和复制,包括在备用服务器上运行只读查询。
minimal 会删除所有日志记录,但从崩溃或立即关闭中恢复所需的信息除外。
logical 添加支持逻辑解码所需的信息。
在 minimal 级别上,可以安全地跳过一些批量操作的WAL日志记录,这可以使这些操作更快(请参见14.4.7节), 但是 minimal 的WAL没有包含足够的信息来从基本备份和WAL日志中重建数据,因此必须使用replica或更高级别来启用WAL归档(archive_mode)和流复制。
在logical级别,将记录与副本相同的信息,以及允许从WAL中提取逻辑更改集所需的信息。 使用logical级别将增加WAL量,尤其是如果为REPLICA IDENTITY FULL配置了许多表并且执行了许多UPDATE和DELETE语句时,尤其如此。
在9.6之前的版本中,此参数还允许值archive和hot_standby。 这些仍被接受,但映射到replica。
2. 修改pg_hba.conf文件添加认证信息
host all all 0.0.0.0/0 md5
host replication all 192.168.1.11/32 md5
3. 启动postgresql服务
pg-master # systemctl start portgresql-12
4. 添加复制用户
pg-master # su - postgres
-bash $ psql
postgres=# CREATE USER repluser REPLICATION LOGIN CONNECTION LIMIT 5 ENCRYPTED PASSWORD 'replpass';
3. 从数据库配置
1. 从节点执行pg_basebackup初始化数据库
pg-slave # pg_basebackup -R -D /var/lib/pgsql/12/data/ -Fp -Xs -v -P -h 192.168.1.10 -p 5432 -U repluser
$PGDATA 目录下产生了 standby.signa 标识文件,同时 postgresql.auto.conf 配置文件增加了 primary_conninfo 参数信息。
pg-slave # cat postgresql.auto.conf
# Do not edit this file manually!
# It will be overwritten by the ALTER SYSTEM command.
primary_conninfo = 'user=repluser password=replpass host=192.168.1.10 port=5432 sslmode=prefer sslcompression=0 gssencmode=prefer krbsrvname=postgres target_session_attrs=any'
2. 修改主配置文件postgresql.conf
hot_standby = on
max_standby_archive_delay = 30s
max_standby_streaming_delay = 30s
wal_receiver_status_interval = 10s
wal_receiver_timeout = 60s
wal_retrieve_retry_interval = 5s
3.启动postgresql服务
pg-slave # systemctl start portgresql-12
二、主从验证
1. 当从节点启动服务后,会有一个“postgres: walreceiver”进程
pg-slave # ps -ef
postgres 7990 7983 0 13:35 ? 00:00:03 postgres: walreceiver streaming 0/90020B0
主节点有一个“postgres: walsender”进程
pg-master # ps -ef
postgres 8951 8493 0 13:35 ? 00:00:00 postgres: walsender repluser 192.168.1.11(35822) streaming 0/90020B0
2. 在主节点查询主从复制信息
postgres=# select * from pg_stat_replication;
pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | backend_xmin | state | sent_lsn | write_lsn | flush_lsn | replay_lsn | write_lag | flush_lag | replay_
lag | sync_priority | sync_state | reply_time
------+----------+----------+------------------+---------------+-----------------+-------------+-------------------------------+--------------+-----------+-----------+-----------+-----------+------------+-----------+-----------+--------
----+---------------+------------+-------------------------------
8951 | 16384 | repluser | walreceiver | 192.168.1.11 | | 35822 | 2020-06-24 13:35:47.923873+08 | | streaming | 0/90020B0 | 0/90020B0 | 0/90020B0 | 0/90020B0 | | |
| 0 | async | 2020-06-24 14:55:17.912174+08
3. 创建一个测试库test
主节点:
postgres=# create database test;
postgres=# \l
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
test | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
(4 rows)
从节点上:
postgres=# \l
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
test | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
(4 rows)
可以看到从节点已将test库的信息同步过来
来源:oschina
链接:https://my.oschina.net/u/3021599/blog/4321592