【PgSQL同步插件】cdc插件之wal2json日常维护

只获取变化，不消费slot：
SELECT * FROM pg_logical_slot_peek_changes('zedb_slot', NULL, NULL);
查询数据库创建的slot
select * from pg_replication_slots ;
slot_name | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin | restart_lsn | confirmed_flus
h_lsn
-----------------------------------------+----------+-----------+--------+----------+-----------+--------+------------+------+--------------+--------------+---------------
------
zedb_slot | wal2json | logical | 16416 | zedb | f | f | | | 12250134 | 442/4B001430 | 442/4C004200

select * from pg_logical_slot_get_changes('zedb_slot', NULL, null);

ERROR: requested WAL segment pg_wal/00000001000004420000004B has already been removed

slot已经建立，而远端的pg_recvlogical停止，停止的这段时间产生的数据库变化是不会被消费的，启动后可以接收到所有的变化。
若wal日志已经清理，需要重建slot或者从备份中找回wal日志
删除复制槽slot
select pg_drop_replication_slot('zedb_slot');