postgresql之流复制监控pg_stat_replication参数

pg_stat_replication参数详解

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
------+----------+---------+------------------+---------------+-----------------+-------------+-------------------------------+--------------+-----------+------------+------------+------------+-------
-----+-----------+-----------+------------+---------------+------------
 4364 |    16384 | repuser | node2            | 192.168.12.11 |                 |       46342 | 2021-11-01 22:20:10.003338-04 |              | streaming | 0/4F508D70 | 0/4F508D70 | 0/4F508D70 | 0/4F50
8D70 |           |           |            |             1 | sync
(1 row)

sent_lsn：wal发送进程最近发送的位置
write_lsn：备库最近写入的wal日志位置
flush_lsn：主库落盘后等待备库接受的wal日志，wal日志流已写入备库，但还没有应用wal日志，并返回确认信息
replay_lsn：主库已落盘，备库已应用wal日志并返回确认信息
write_lag:主库已落盘，等待备库落盘，且wal日志流还在操作系统缓存中
sync_priority:优先级备库
sync_state:同步状态