ubuntu-postgres-diagnostics

gistfile1.txt

    Certify that postgresql service is running, using sudo service postgresql start
    Run pg_lsclusters from your terminal

    Check what is the cluster you are running, the output should be something like:

    Version - Cluster Port Status Owner Data directory

    9.6 ------- main -- 5432 online postgres /var/lib/postgresql/9.6/main

        Disregard the '---' signs, as they are being used there only for alignment. The important information are the version and the cluster. You can also check whether the server is running or not in the status column.

    Copy the info from the version and the cluster, and use like so: pg_ctlcluster <version> <cluster> start, so in my case, using version 9.6 and cluster 'main', it would be pg_ctlcluster 9.6 main start
    If something is wrong, then postgresql will generate a log, that can be accessed on /var/log/postgresql/postgresql-<version>-main.log, so in my case, the full command would be sudo nano /var/log/postgresql/postgresql-9.6-main.log.
    The output should show what is the error.

        2017-07-13 16:53:04 BRT [32176-1] LOG: invalid authentication method "all"
        2017-07-13 16:53:04 BRT [32176-2] CONTEXT: line 90 of configuration file "/etc/postgresql/9.5/main/pg_hba.conf"
        2017-07-13 16:53:04 BRT [32176-3] FATAL: could not load pg_hba.conf

    Fix the errors and restart postgresql service through sudo service postgresql restart and it should be fine.