Is the server running on host “localhost” (::1) an

Question

Before anything, please note that I have found several similar questions on Stack Overflow and articles all over the web, but none of those helped me fix my issue:

• PG Error could not connect to server: Connection refused Is the server running on port 5432?
• PG::ConnectionBad - could not connect to server: Connection refused
• psql: could not connect to server: Connection refused

Now, here is the issue:

• I have a Rails app that works like a charm.
• With my collaborator, we use GitHub to work together.
• We have a master and an mvp branches.
• I recently updated my git version with Homebrew (Mac).
• We use Foreman to start our app locally.

Now, when I try to launch the app locally, I get the following error:

PG::ConnectionBad at /
could not connect to server: Connection refused
    Is the server running on host "localhost" (::1) and accepting
    TCP/IP connections on port 5432?
could not connect to server: Connection refused
    Is the server running on host "localhost" (127.0.0.1) and accepting
    TCP/IP connections on port 5432?

I tried to reboot my computers several times.

I also checked the content of /usr/local/var/postgres:

PG_VERSION      pg_dynshmem     pg_multixact    pg_snapshots    pg_tblspc       postgresql.conf
base            pg_hba.conf     pg_notify       pg_stat         pg_twophase     postmaster.opts
global          pg_ident.conf   pg_replslot     pg_stat_tmp     pg_xlog         server.log
pg_clog         pg_logical      pg_serial       pg_subtrans     postgresql.auto.conf

As you can see, there is no postmaster.pid file in there.

Any idea how I could fix this?

Answer 1

First I tried

lsof -wni tcp:5432 but it doesn't show any PID number.

Second I tried

Postgres -D /usr/local/var/postgres and it showed that server is listening.

So I just restarted my mac to restore all ports back and it worked for me.

Answer 2

I resolved the issue via this command

pg_ctl -D /usr/local/var/postgres start

At times, you might get this error

pg_ctl: another server might be running; trying to start server anyway

So, try running the following command and then run the first command given above.

pg_ctl -D /usr/local/var/postgres stop

Answer 3

Most likely it's because your system shutdown unexpectedly

Try

postgres -D /usr/local/var/postgres

You might see

FATAL:  lock file "postmaster.pid" already exists
HINT:  Is another postmaster (PID 449) running in data directory "/usr/local/var/postgres"?

Then try

kill -9 PID

example

kill -9 419

And it should start postgres normally

Answer 4

This worked in my case:

brew uninstall postgresql
rm -fr /usr/local/var/postgres/
brew install postgresql

Answer 5

For Docker users: In my case it was caused by excessive docker image size. You can remove unused data using prune command:

docker system prune --all --force --volumes

Warning: as per manual (docker system prune --help):

This will remove:

• all stopped containers
• all networks not used by at least one container
• all dangling images
• all dangling build cache

Answer 6

I often encounter this problem on windows,the way I solved the problem is Service - Click PostgreSQL Database Server 8.3 - Click the second tab "log in" - choose the first line "the local system account".