I have one Primary server and one Standby server. They are doing streaming replication well.
I did some testing. I broke the network connection between them for a few minutes, and then restored the network. I found the both the WAL sender and WAL receiver were stopped and the restarted.
I wonder how WAL receiver process is stopped and restarted. I have checked the code hoping to find out the answer, but I don't have any clue.