详谈pg逻辑复制系列之逻辑复制的搭建（二）

**发布端** 1. 查看发布端的相关参数并修改为合适值```bash alter system set wal_level =logical; alter system set max_replication_slots=8; alter system set max_wal_senders=10; --应该将此参数设置的比 max_replication_slots 参数要大 --修改参数后重启数据库,使参数生效 pg_ctl restart ```2. 发布节点创建发布```bash postgres=# create user a password'root123'; CREATE ROLE postgres=# create database a owner a; CREATE DATABASE postgres=# \c a a -- 创建发布测试表 a=> create table badtable (id serial primary key,name varchar(32),age int,hobby a(> text,date timestamp); CREATE TABLE a=> insert into badtable (name,age,hobby,date) values ('postgres', a(> (random()*100)::int,md5('random()::highgo'), a(> generate_series('2008-03-01 00:00'::timestamp,'2008-03-04 23:00', '10 hours')); INSERT 0 10 a=> select count(*) from badtable;  count  -------     10 (1 row)  --创建发布 [root@rhel1 data]# psql a a a=> create publication pub1 for table badtable ; --查询发布 a=> select * from pg_publication;   oid  | pubname | pubowner | puballtables | pubinsert | pubupdate | pubdelete | pubtruncate  -------+---------+----------+--------------+-----------+-----------+-----------+-------------  16399 | pub1    |    16385 | f            | t         | t         | t         | t (1 row) ```3. 发布节点创建逻辑复制用户```bash a=> \c a postgres a=# create user logicalrep password'root123' replication; ``` 4.配置replication网络访问控制```bash $ vi $PGDATA/pg_hba.conf #IPv4 host all all 0.0.0.0/0 md5 #replication host replication all 0.0.0.0/0 md5 $ pg_ctl reload ```**订阅端配置** 1. 查看相关参数并修改为合适值```bash alter system set max_replication_slots=8; alter system set max_logical_replication_workers=8;  $ vi $PGDATA/pg_hba.conf # IPv4 local connections: host    all             all             127.0.0.1/32            md5 host    all             all             0.0.0.0/0               md5 # replication privilege. local   replication     all                                     md5 host    replication     all             127.0.0.1/32            md5 host    replication     all             ::1/128                 md5 host    replication     all             0.0.0.0/0               md5 ```2. 订阅节点创建订阅```bash --先将订阅端表创建 postgres=# create user b password'root23'; postgres=# create database b owner b; postgres=# \c b b b=> create table badtable (id serial primary key,name varchar(32),age int,hobby b(> text,date timestamp);        --创建订阅 b=> \c b postgres                           b=# create subscription sub1 connection 'host=192.168.230.101 port=5866 dbname=a user=logicalrep password=root123' publication pub1; NOTICE:  created replication slot "sub1" on publisher     -----备端连到主端创建逻辑复制槽   作用也是保证没有被订阅端解析的wal日志被主端删除 CREATE SUBSCRIPTION --订阅节点查询订阅信息 select * from pg_subscription; ``` 3. 查询订阅端表```bash  2021-03-15 15:04:37.786 CST [20014] LOG:  logical replication table synchronization worker for subscription "sub1", table "badtable" has started NOTICE:   2021-03-15 15:04:37.928 CST [20014] ERROR:  could not start initial contents copy for table "public.badtable": ERROR:  permission denied for table badtable 2021-03-15 15:04:37.937 CST [20001] LOG:  background worker "logical replication worker" (PID 20014) exited with exit code 1 2021-03-15 15:04:42.961 CST [20015] LOG:  logical replication table synchronization worker for subscription "sub1", table "badtable" has started --没有数据同步,主要是复制用户logicalrep对表所属的schema及表没有读写权限 --在发布端进行表授权 a=> grant usage on schema public to logicalrep; a=> grant select on badtable to logicalrep ; a=> alter default privileges in schema public grant select on tables to logicalrep ; --订阅端再次查询数据 b=> select * from badtable;  id |  name  | age |              hobby               |        date          ----+--------+-----+----------------------------------+---------------------   1 | postgres |  81 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-01 00:00:00   2 | postgres |  58 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-01 10:00:00   3 | postgres |  14 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-01 20:00:00   4 | postgres |  66 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-02 06:00:00   5 | postgres |  37 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-02 16:00:00   6 | postgres |  52 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-03 02:00:00   7 | postgres |  21 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-03 12:00:00   8 | postgres |  78 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-03 22:00:00   9 | postgres |  20 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-04 08:00:00  10 | postgres |  31 | 311e7462a6242cbc0578f9d6d91d5d33 | 2008-03-04 18:00:00 --查询状态 b=# select * from pg_subscription;   oid  | subdbid | subname | subowner | subenabled |                                subconninfo                                  | subslotname | subsynccommit | subpublications  -------+---------+---------+----------+------------+----------------------------------------------------------- -----------------+-------------+---------------+-----------------  16400 |   16385 | sub1    |     9999 | t          | host=192.168.230.101 port=5866 dbname=a user=logicalrep pa ssword=root123 | sub1        | off           | {pub1} (1 row) ```