hoasung01 · November 27, 2015 01:42
diff --git a/loi-PG::ConnectionBad b/loi-PG::ConnectionBad
 It could be as simple as a stale PID file. It could be failing silently because your computer didn't complete the shutdown process completely which means postgres didn't delete the PID (process id) file. The PID file is used by postgres to make sure only one instance of the server is running at a time. So when it goes to start again, it fails because there is already a PID file which tells postgres that another instance of the server was started (even though it isn't running, it just didn't get to shutdown and delete the PID).

 To fix it remove/rename the PID file. Find the postgres data directory. On a MAC using homebrew it is /usr/local/var/postgres/, other systems it might be /usr/var/postgres/.
 To make sure this is the problem, look at the log file (server.log). On the last lines you will see: FATAL:  lock file "postmaster.pid" already exists
 HINT:  Is another postmaster (PID 347) running in data directory "/usr/local/var/postgres"?
 If so, rm postmaster.pid
 Restart your server. On a mac using launchctl (with homebrew) the following commands will restart the server.

 launchctl unload homebrew.mxcl.postgresql.plist  
 launchctl load -w homebrew.mxcl.postgresql.plist
	It could be as simple as a stale PID file. It could be failing silently because your computer didn't complete the shutdown process completely which means postgres didn't delete the PID (process id) file. The PID file is used by postgres to make sure only one instance of the server is running at a time. So when it goes to start again, it fails because there is already a PID file which tells postgres that another instance of the server was started (even though it isn't running, it just didn't get to shutdown and delete the PID).

	To fix it remove/rename the PID file. Find the postgres data directory. On a MAC using homebrew it is /usr/local/var/postgres/, other systems it might be /usr/var/postgres/.
	To make sure this is the problem, look at the log file (server.log). On the last lines you will see: FATAL: lock file "postmaster.pid" already exists
	HINT: Is another postmaster (PID 347) running in data directory "/usr/local/var/postgres"?
	If so, rm postmaster.pid
	Restart your server. On a mac using launchctl (with homebrew) the following commands will restart the server.

	launchctl unload homebrew.mxcl.postgresql.plist
	launchctl load -w homebrew.mxcl.postgresql.plist