",2013-08-12 20:43:41 CST,,0,LOG,00000,"connection received: host=192.25.10.71 port=46086",,,,,,,,,""
2013-08-12 20:43:41.514 CST,"repuser","",21066,"192.25.10.71:46086",5208d87d.524a,2,"authentication",2013-08-12 20:43:41 CST,2/1198,0,LOG,00000,"replication connection authorized: user=repuser",,,,,,,,,""
2013-08-12 20:43:41.514 CST,"repuser","",21066,"192.25.10.71:46086",5208d87d.524a,3,"startup",2013-08-12 20:43:41 CST,2/0,0,FATAL,53300,"number of requested standby connections exceeds max_wal_senders (currently 0)",,,,,,,,,"walreceiver"
2013-08-12 20:43:41.515 CST,"repuser","",21066,"192.25.10.71:46086",5208d87d.524a,4,"startup",2013-08-12 20:43:41 CST,,0,LOG,00000,"disconnection: session time: 0:00:00.002 user=repuser database= host=192.25.10.71 port=46086",,,,,,,,,"wa
lreceiver"
...
遇到如此问题，则需要检查postgresql.conf文件的max _wal_senders参数了。
3.参数生效
文档上说明需要重启DB使之生效，如果动态使之生效会报错如下：
[postgres@proxy1 ]$ psql
psql (9.2.4)
Type "help" for help.
postgres=# show max_wal_senders ;
max_wal_senders
-----------------
0
(1 row)
postgres=# set max_wal_senders=1;
ERROR: parameter "max_wal_senders" cannot be changed without restarting the server
postgres=#