postgres PEM server, issue connecting the data base - postgresql

Question

I'm not good with Postgres database troubleshooting, but I have a big project data base running on it.
Today suddenly I'm getting an error while I try to access my server, attached is the picture of the error screenshot. I really don't want to lose my data because its not backed up for few months.
I tried to reinstall but it says the port is messed up somewhere.
The message while I reinstall is:
"psql:could not connect to server: Connection refused (0x0000274D/10061)
Is the server running on host "127.0.0.1" and accepting
TCP/IP connection on port 5432?

Answer 1

Is the server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432? That are two questions you could answer:
Is the server running on host "127.0.0.1" (aka localhost) use:
ps auxw | grep postgres # to answer this question
... accepting TCP/IP connections on port 5432? there are several ways to answer this question:
psql -h 127.0.0.1 -p 5432 postgres
telnet localhost 5432
nmap -p 5432 localhost
The result for (1) should be like:
postgres 30402 0.0 0.1 238488 12924 ? S 12:09 0:01 /opt/postgres/bin/postmaster -D /data/db/postgres/pgdata
postgres 30409 0.0 0.0 94644 1308 ? Ss 12:09 0:00 postgres: logger process
postgres 30411 0.0 0.3 238628 46964 ? Ss 12:09 0:01 postgres: checkpointer process
postgres 30412 0.0 0.0 238628 4764 ? Ss 12:09 0:00 postgres: writer process
postgres 30413 0.0 0.0 238628 5832 ? Ss 12:09 0:00 postgres: wal writer process
postgres 30414 0.0 0.0 239036 2820 ? Ss 12:09 0:01 postgres: autovacuum launcher process
postgres 30415 0.0 0.0 97884 2460 ? Ss 12:09 0:03 postgres: stats collector process
The result for (2) should be like:
Password:
The result for (3) should be like:
Trying ::1...
Connected to localhost.localdomain.
Escape character is '^]'.
The result for (4) should be like:
Starting Nmap 6.40 ( http://nmap.org ) at 2016-05-18 15:14 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000050s latency).
Other addresses for localhost (not scanned): 127.0.0.1
rDNS record for 127.0.0.1: localhost.localdomain
PORT STATE SERVICE
5432/tcp open postgresql
Nmap done: 1 IP address (1 host up) scanned in 0.04 seconds
if (1) fails (gives no relevant output) postgres is obviously not running.
you didn't start it (there should be a file for the service in /etc/init.d/)
you attempted to start it, but it failed to startup
the binaries were not present, not found, or wrong
the data directory was not present, not found, or had the wrong owner/rights
the data directory contained files, but not for this version
if (2,3,4) fail (give no relevant output)
postgres is not listening on the inet socket, but only on the unix-domain socket : check your config-file for listen_address = '*'
finally, there could be a firewall-issue. (Check your iptables settings. or whatever)