检查postgres复制状态

Question

有人可以建议检查pgsql复制状态的步骤以及何时说复制没有正确进行？

我们使用pgsql9.0和pgsql9.4的流式复制

感谢。

Answer 1

在您的主服务器上，pg_stat_replication提供有关正在进行的复制的数据：

select client_addr, state, sent_location, write_location,
        flush_location, replay_location from pg_stat_replication;

在postgresql v10上：

select client_addr, state, sent_lsn, write_lsn,
    flush_lsn, replay_lsn from pg_stat_replication;

Answer 2

在PostgreSQL中显示复制状态

在服务器上

postgres=# select usename,application_name,client_addr,backend_start,state,sync_state from pg_stat_replication ;

usename   | application_name |  client_addr   |         backend_start         |   state   | sync_state 
------------+------------------+----------------+-------------------------------+-----------+------------
replicator | walreceiver      | 192.168.10.132 | 2018-07-06 06:12:20.786918+03 | streaming | async
(1 row)

在客户端上

postgres=# select pg_is_in_recovery();
 pg_is_in_recovery 
-------------------
 t
 (1 row)


postgres=# select pg_last_xlog_receive_location();
 pg_last_xlog_receive_location 
-------------------------------
 0/540C1DB8


postgres=# select pg_last_xlog_replay_location();
 pg_last_xlog_replay_location 
------------------------------
 0/540C1DB8
 (1 row)

postgres=#    SELECT CASE WHEN pg_last_xlog_receive_location() = pg_last_xlog_replay_location()
                  THEN 0
                ELSE EXTRACT (EPOCH FROM now() - pg_last_xact_replay_timestamp())
              END AS log_delay;
 log_delay 
-----------
 0
 (1 row)

Answer 3

我通常使用以下SQL查询来检查Postgres v11的状态。

在母版上：

select * from pg_stat_replication;

在副本上（在我的情况下为流复制）：

select * from pg_stat_wal_receiver;