分布式postgres部署不同步

我设置了一个分布式postgres数据库系统，并使用hot_standby wal_level配置了复制 .

有一个中央主数据库，其中有多个副本（目前全世界有15个）用作只读实例 - 因此不需要故障转移 - 我们只想将数据同步到我们可以读取它们的远程位置 .

主：

wal_level = hot_standby
max_wal_senders = 20
checkpoint_segments = 8    
wal_keep_segments = 8

客户：

wal_level = hot_standby
max_wal_senders = 3
checkpoint_segments = 8    
wal_keep_segments = 8 
hot_standby = on

客户端的/var/lib/postgresql/9.4/recovery.conf：

standby_mode = 'on'
primary_conninfo = 'host=<IP of master> port=5432 user=replicator password=xxxx sslmode=require'
trigger_file = '/tmp/postgresql.trigger'

复制开始 - 有些日子似乎都很好 . 几天之后，主人似乎没有接受更多连接进行复制......

客户：

2017-05-04 01:16:51 UTC [9608-1] FATAL:  could not connect to the primary server: FATAL:  sorry, too many clients already
2017-05-04 01:16:57 UTC [10807-1] FATAL:  could not connect to the primary server: FATAL:  sorry, too many clients already
2017-05-04 01:17:02 UTC [12022-1] FATAL:  could not connect to the primary server: FATAL:  sorry, too many clients already
2017-05-04 01:17:06 UTC [13217-1] FATAL:  could not connect to the primary server: FATAL:  remaining connection slots are reserved for non-replication superuser connections
...

主：

然后loag充满了下面的消息 - 它永远不会恢复......

2017-05-04 08:44:14 UTC [24850-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-05-04 08:44:19 UTC [25958-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-05-04 08:44:24 UTC [27063-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-05-04 08:44:29 UTC [28144-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-05-04 08:44:34 UTC [29227-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-05-04 08:44:39 UTC [30316-1] replicator@[unknown] ERROR:  requested WAL segment 000000010000003500000014 has already been removed
...

客户：

2017-04-30 11:26:22 UTC [28474-1] LOG:  started streaming WAL from primary at 35/14000000 on timeline 1
2017-04-30 11:26:22 UTC [28474-2] FATAL:  could not receive data from WAL stream: ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-04-30 11:26:26 UTC [29328-1] LOG:  started streaming WAL from primary at 35/14000000 on timeline 1
2017-04-30 11:26:26 UTC [29328-2] FATAL:  could not receive data from WAL stream: ERROR:  requested WAL segment 000000010000003500000014 has already been removed
2017-04-30 11:26:31 UTC [30394-1] LOG:  started streaming WAL from primary at 35/14000000 on timeline 1
2017-04-30 11:26:31 UTC [30394-2] FATAL:  could not receive data from WAL stream: ERROR:  requested WAL segment 000000010000003500000014 has already been removed
...

所以我的问题：

• 是否有更好的方法来将更改同步到远程只读实例，或者我只是在配置中出现错误，使我的复制在一段时间后中断？