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本篇内容主要讲解“PostgreSQL 12 搭建流复制的过程是什么”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让丸趣 TV 小编来带大家学习“PostgreSQL 12 搭建流复制的过程是什么”吧!
主库
创建复制用户
[pg12@localhost pg120db]$ psql -c CREATE USER replicator WITH REPLICATION ENCRYPTED PASSWORD test -d testdb
Timing is on.
Expanded display is used automatically.
CREATE ROLE
Time: 30.796 ms常规参数配置
[pg12@localhost pg120db]$ grep listen postgresql.conf
listen_addresses = * # what IP address(es) to listen on;
pg12@localhost pg120db]$ grep replication pg_hba.conf
# DATABASE can be all , sameuser , samerole , replication , a
# keyword does not match replication . Access to replication
# all , sameuser , samerole or replication makes the name lose
# Allow replication connections from localhost, by a user with the
# replication privilege.
local replication all trust
host replication all 127.0.0.1/32 trust
host replication all 192.168.0.0/16 md5
host replication all ::1/128 trust
[pg12@localhost pg120db]$重新加载配置参数
[pg12@localhost pg120db]$ psql -c select pg_reload_conf() -d testdb
Timing is on.
Expanded display is used automatically.
pg_reload_conf
----------------
t
(1 row)
Time: 454.580 ms确认该库为 master 主库
[pg12@localhost pg120db]$ psql -c select pg_is_in_recovery() -d testdb
Timing is on.
Expanded display is used automatically.
pg_is_in_recovery
-------------------
f
(1 row)
Time: 23.530 ms
[pg12@localhost pg120db]$备库
使用 pg_basebackup 执行主库备份
[pg12@localhost ~]$ pg_basebackup -h 192.168.26.28 -U replicator -p 5432 -D $PGDATA -Fp -Xs -P -R
Password:
426401/9113562 kB (4%), 0/1 tablespace其中 -Fp 表示以 plain 格式数据，-Xs 表示以 stream 方式包含所需的 WAL 文件，- P 表示显示进度，- R 表示为 replication 写配置信息。
备份完成，使用 - R 选项，在 data 目录下自动生成 standby.signal“信号”文件（可手工使用 touch 命令生成）以及更新了 postgresql.auto.conf 文件，postgresql.auto.conf 中写入了主库的连接信息（可手工添加 primary_conninfo 信息）。
[pg12@localhost ~]$ pg_basebackup -h 192.168.26.28 -U replicator -p 5432 -D $PGDATA -Fp -Xs -P -R
Password:
9113571/9113571 kB (100%), 1/1 tablespace
[pg12@localhost ~]$
[pg12@localhost ~]$ cd $PGDATA
[pg12@localhost testdb]$ ls
backup_label pg_commit_ts pg_log pg_replslot pg_stat_tmp PG_VERSION postgresql.conf
base pg_dynshmem pg_logical pg_serial pg_subtrans pg_wal standby.signal
current_logfiles pg_hba.conf pg_multixact pg_snapshots pg_tblspc pg_xact
global pg_ident.conf pg_notify pg_stat pg_twophase postgresql.auto.conf
[pg12@localhost testdb]$ ll standby.signal
-rw-------. 1 pg12 pg12 0 Nov 12 16:35 standby.signal
[pg12@localhost testdb]$
[pg12@localhost testdb]$ cat postgresql.auto.conf
# Do not edit this file manually!
# It will be overwritten by the ALTER SYSTEM command.
primary_conninfo = user=replicator password=test host=192.168.26.28 port=5432 sslmode=prefer sslcompression=0 gssencmode=prefer krbsrvname=postgres target_session_attrs=any
[pg12@localhost testdb]$
[pg12@localhost testdb]$ grep primary_conninfo postgresql.*
postgresql.auto.conf:primary_conninfo = user=replicator password=test host=192.168.26.28 port=5432 sslmode=prefer sslcompression=0 gssencmode=prefer krbsrvname=postgres target_session_attrs=any
postgresql.conf:#primary_conninfo = # connection string to sending server
[pg12@localhost testdb]$在 PG 11 中，需要创建 recovery.conf 文件，在此文件中配置 standby_mode 和 primary_conninfo 参数，PG 12 已不再需要该文件，改为 standby.signal 文件以及通过配置参数直接设置。
备库启动数据库，通过 pg_is_in_recovery 确认是否正常配置
[pg12@localhost testdb]$ pg_ctl -D $PGDATA start
waiting for server to start....2019-11-12 16:46:31.635 CST [20436] LOG: starting PostgreSQL 12.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-36), 64-bit
2019-11-12 16:46:31.636 CST [20436] LOG: listening on IPv4 address 0.0.0.0 , port 5432
2019-11-12 16:46:31.636 CST [20436] LOG: listening on IPv6 address :: , port 5432
2019-11-12 16:46:31.638 CST [20436] LOG: listening on Unix socket /tmp/.s.PGSQL.5432
2019-11-12 16:46:31.750 CST [20436] LOG: redirecting log output to logging collector process
2019-11-12 16:46:31.750 CST [20436] HINT: Future log output will appear in directory pg_log .
done
server started
[pg12@localhost testdb]$ psql -c select pg_is_in_recovery() -d testdb
pg_is_in_recovery
-------------------
t
(1 row)
[pg12@localhost testdb]$完成搭建
通过 pg_stat_replication 可查询复制状态（异步复制）
[pg12@localhost pg120db]$ psql -x -c select * from pg_stat_replication -d testdb
Timing is on.
Expanded display is used automatically.
-[ RECORD 1 ]----+------------------------------
pid | 4503
usesysid | 155959
usename | replicator
application_name | walreceiver
client_addr | 192.168.26.25
client_hostname |
client_port | 35172
backend_start | 2019-11-12 16:46:31.000236+08
backend_xmin |
state | streaming
sent_lsn | 6/A3000148
write_lsn | 6/A3000148
flush_lsn | 6/A3000148
replay_lsn | 6/A3000148
write_lag |
flush_lag |
replay_lag |
sync_priority | 0
sync_state | async
reply_time | 2019-11-12 16:48:32.509887+08
Time: 149.682 ms
[pg12@localhost pg120db]$到此，相信大家对“PostgreSQL 12 搭建流复制的过程是什么”有了更深的了解，不妨来实际操作一番吧！这里是丸趣 TV 网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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