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:
Now, here is the issue:
master
and an mvp
branches.git
version with Homebrew (Mac).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?
This question is related to
ruby-on-rails
ruby
postgresql
ruby-on-rails-3
ruby-on-rails-4
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
In my case I forgot to change the database from postgres (on my production) back to sqlite3 which I was using for development.
Step 1:
cd /etc/postgresql/12/main/
open file named postgresql.conf
sudo nano postgresql.conf
add this line to that file
listen_addresses = '*'
then open file named pg_hba.conf
sudo nano pg_hba.conf
and add this line to that file
host all all 0.0.0.0/0 md5
It allows access to all databases for all users with an encrypted password
restart your server
sudo /etc/init.d/postgresql restart
In my case
Run => service.msc => Restart
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.
This worked in my case:
brew uninstall postgresql
rm -fr /usr/local/var/postgres/
brew install postgresql
This worked for me: run
sudo lsof -i :<port_number>
after that it will display the PID which is currently attached to the process.
After that run sudo kill -9 <PID>
if that doesn't work, try the solution offered by user8376606 it would definitely work!
I had almost just as same error with my Ruby on Rails application running postgresql(mac). This worked for me:
brew services restart postgresql
run postgres -D /usr/local/var/postgres
and you should see something like:
FATAL: lock file "postmaster.pid" already exists
HINT: Is another postmaster (PID 379) running in data directory "/usr/local/var/postgres"?
Then run kill -9 PID
in HINT
And you should be good to go.
It also gives the same error if you just stop your PostgreSQL app. You just need to start it again. (PostgreSQL 11)
The postgresql server might be down and the solution might be as simple as running:
sudo service postgresql start
which fixed the issue for me.
If you want to restart Postgresql on Linux, then you have to use the following command.
/etc/init.d/postgresql restart
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".
I have faced the same issue and I was unable to start the postgresql server and was unable to access my db even after giving password, and I have been doing all the possible ways.
This solution worked for me,
For the Ubuntu users: Through command line, type the following commands:
1.service --status-all (which gives list of all services and their status. where "+" refers to running and "-" refers that the service is no longer running)
check for postgresql status, if its "-" then type the following command
2.systemctl start postgresql (starts the server again)
refresh the postgresql page in browser, and it works
For the Windows users:
Search for services, where we can see list of services and the right click on postgresql, click on start and server works perfectly fine.
This could be caused by the pid file created for postgres which has not been deleted due to unexpected shutdown. To fix this, remove this 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/
Remove pid file by running:
rm postmaster.pid
Restart postgress. On Mac, run:
brew services restart postgresql
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
I encountered a similar problem when I was trying to connect my Django application to PostgreSQL database.
I wrote my Dockerfile
with instructions to setup the Django project followed by instructions to install PostgreSQL and run Django server in my docker-compose.yml
.
I defined two services in my docker-compose-yml
.
services:
postgres:
image: "postgres:latest"
environment:
- POSTGRES_DB=abc
- POSTGRES_USER=abc
- POSTGRES_PASSWORD=abc
volumes:
- pg_data:/var/lib/postgresql/data/
django:
build: .
command: python /code/manage.py runserver 0.0.0.0:8004
volumes:
- .:/app
ports:
- 8004:8004
depends_on:
- postgres
Unfortunately whenever I used to run docker-compose up
then same err. used to pop up.
And this is how my database was defined in Django settings.py
.
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'abc',
'USER': 'abc',
'PASSWORD': 'abc',
'HOST': '127.0.0.1',
'PORT': '5432',
'OPTIONS': {
'client_encoding': 'UTF8',
},
}
}
So, In the end I made use of docker-compose
networking which means if I change the host
of my database to postgres
which is defined as a service in docker-compose.yml
will do the wonders.
So, Replacing 'HOST': '127.0.0.1'
=> 'HOST': 'postgres'
did wonders for me.
After replacement this is how your Database config in settings.py
will look like.
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'abc',
'USER': 'abc',
'PASSWORD': 'abc',
'HOST': 'postgres',
'PORT': '5432',
'OPTIONS': {
'client_encoding': 'UTF8',
},
}
}
Wild stab in the dark: You're on a machine with an IPv6 resolver where localhost
defaults to the IPv6 address ::1
, but listen_addresses
in postgresql.conf
is set to 127.0.0.1
or 0.0.0.0
not *
or you're using an older PostgreSQL built with a C library that doesn't have transparent IPv6 support.
Change listen_addresses
to localhost
and make sure localhost
resolves to both the IPv4 and IPv6 addresses, or set it to ::1, 127.0.0.1
to explicitly specify both IPv4 and IPv6. Or just set it to *
to listen on all interfaces. Alternately, if you don't care about IPv6, connect to 127.0.0.1
instead of localhost
.
See this Google search or this Stack Overflow search for more information.
(Posting despite my close-vote because I voted the question for migration).
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
Source: Stackoverflow.com