(...Transactions started during hot standby will never be assigned a transaction ID and cannot write to the system write-ahead log. Therefore, the following actions will produce error messages:....)
My application must subscribe to the master database always because "listen" doesn't work on slave database and also run "READ" query in the master database because there could be some delay between master & slave database. If I run "READ" query in the slave database immediately after receiving notification, it is not guaranteed that I can retrieve the last stats.
This problem might be solved if slave database supports "LISTEN" query.
How are you guys using NOTIFY/LISTEN in master/slave databases?