Homebrew postgres broken

Question

I installed Postgresql 9.4.0 installed on my Mac (10.10.1/Yosemite) using homebrew. It does not work.

I have created the softlink to /usr/local/opt/postgresql/homebrew.mxcl.postgresql.plist in ~/Library/LaunchAgents.

If I try to manually load postgres I get the message that the "Operation is in progress"

> launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
/usr/local/Cellar/postgresql/9.4.0/homebrew.mxcl.postgresql.plist: Operation already in progress

However postgres does not appear to be running.

> ps auxw | grep post
billmcn           670   0.0  0.0  2424272    452 s000  R+   10:12PM   0:00.01 grep post

and I cannot connect with the command line client.

> psql
psql: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

To my knowledge I have tried all the fixes suggested on other Stackoverflow threads discussing this problem. Specifically:

• I have uninstalled and reinstalled postgres and the accompanying Ruby gem. There is no postgres 8.0 version on my machine.
• I have verified that the psql client program is the 9.4.0 version installed by Homebrew and not a Mac system binary.
• I have verified that the /usr/local/var/postgres/postmaster.pid does not exist.
• I have rebooted the machine.

I did have Homebrew postgres working on this machine earlier. I think what broke it is upgrading from version 8 to version 9 but I'm not sure.

I don't have any databases I need to preserve. I'm willing to start clean with postgres; I just need to get it to work now. Any ideas?

---

The issue appears to have been permissions on the /usr/local/var/postgres directory. Here is what my var directory looked like when things weren't working.

ll /usr/local/var/
drwxr-xr-x  3 billmcn  admin  102 Dec 20 12:44 cache
drwxr--r--  2 root     admin   68 Dec 29 21:37 postgres

(whoami = "billmcn")

I deleted /usr/local/var/postgres, uninstalled and reinstalled postgres, and now it looks like this.

ll /usr/local/var/
drwxr-xr-x   3 billmcn  admin  102 Dec 20 12:44 cache
drwx------  23 billmcn  admin  782 Dec 30 10:51 postgres

Not sure how it got into this state because I don't remember futzing with the permissions on this directory, but no matter. It works now.

Answer 1

I had this same problem. The primary issue here is that the initdb step of installation will create the directory with root ownership instead of as the user on a Mac. To solve this issue:

Create the data directory before running initdb and set permissions of 0700

rm -rf /usr/local/var/postgres  # in case this is not your first try
mkdir /usr/local/var/postgres
chmod 0700 /usr/local/var/postgres

Then run initdb and it will respect the permissions of the data directory.

initdb -D /usr/local/var/postgres

For grins and giggles, create a test db named after your user:

createdb `whoami`

Login to test:

psql

Answer 2

After trying to install postgresql with Homebrew, I got this:

Warning: postgresql-9.5.2 already installed, it's just not linked

So I tried:

brew link postgresql

And got this error:

Linking /usr/local/Cellar/postgresql/9.5.2... 
Error: Could not symlink share/man/man3/SPI_connect.3
/usr/local/share/man/man3 is not writable.

It seemed to be a write permission matter, so I did:

sudo chown -R `whoami` /usr/local/share/man/

It did the trick because, then I was able to do (without error):

brew link postgresql

Answer 3

Please note that their is a thread on Homebrew's github dealing with this issue: https://github.com/Homebrew/homebrew/issues/35240

---

I have had a similar issue. James answer helped me solve it. But I then ran into the issue jbk is mentioning (after having deleted /usr/local/var/postgres, it kept on being recreated).

The issue is that if you have created the symlink:

ln -sfv /usr/local/opt/postgresql/*.plist ~/Library/LaunchAgents

and launched the process:

launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

you should first unload it:

launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

before running James's commands.

rm -rf /usr/local/var/postgres  # in case this is not your first try
mkdir /usr/local/var/postgres
chmod 0700 /usr/local/var/postgres

In addition, if, like me, you have an admin user managing homebrew and a regular user who will be using pgsl for development purpose, James command should be run as super user:

sudo -s

and ownership over the postgres directory should be given to your dev user:

chown my-dev-user /usr/local/var/postgres

The following command, run as the dev user, should then properly populate the directory:

createdb `whoami`

Running:

psql -l

should show you the tables and user permissions in postgre after such manipulations.

Hope this helps.

Answer 4

In case anyone upgraded from a previous version, dont forget to:

brew postgresql-upgrade-database

That will solve the problem by upgrading your existing databases to the version you upgraded postgres to.

Answer 5

I had to delete the .pid file after seeing this in the logs

/usr/local/var/log/postgres.log

2021-10-10 19:05:27.468 BST [41868] FATAL:  lock file "postmaster.pid" already exists
2021-10-10 19:05:27.468 BST [41868] HINT:  Is another postmaster (PID 820) running in data directory "/usr/local/var/postgres"?

rm /usr/local/var/postgres/postmaster.pid

I installed it using brew

Answer 6

based on @James answer this is what I did on my M1 Monterey machine. For me the directory differed.

DANGER: In the comments it has been pointed out that my script deletes the database.

In terminal:

#to fix postgresql of existing installation
cd /opt/homebrew/var
rm -rf postgres
mkdir postgres
chmod 0700 postgres
initdb -D postgres

#install postgres
echo "installing postgres..."
brew install postgresql
brew services restart postgresql
createuser postgres -s

I then could brew install --cask pgadmin4 and run pgadmin from Applications and connect to 127.0.0.1.

Answer 7

For posterity, I had this issue and wanted to note what worked for me.

I am running postgres 11.2 on High Sierra. I had recently upgraded from postgres 10 with brew postgresql-upgrade-database.

I kept getting the error psql: could not connect to server: No such file or directory, and my server.log indicated is another postmaster (PID 5894) running in data directory "/usr/local/var/postgres"?

I tried several solutions including restarting my computer, deleting postmaster.pid, using brew services restart postgres, but to no avail. I eventually stumbled on the solution:

brew unlink postgresql && brew link postgresql

No idea why this worked, but putting it here mostly so I can reference it myself in the future! Throw stuff at the wall till it sticks!

Answer 8

I recently had a problem which began when I upgraded some brew updates / upgrades, mainly python versions etc. What worked for me.

brew uninstall postgres
brew install [email protected]
echo 'export PATH="/usr/local/opt/[email protected]/bin:$PATH"' > ~/.zshrc
# you may need > ~/.bashrc if you use bash

I needed pg_dump, pg_restore etc so to get that working I did

brew install libpq

Start the service

brew services start [email protected]

From here I would have expected everything to work but still all rails db commands were giving error that server was not running. This final bit was the missing piece of the puzzle which finally solved it for me.

gem uninstall pg
gem install pg -v 0.20.0 # which was set in Gemfile
# could also just probably do bundle install instead.

Answer 9

Check @leo_chaz_maltrait for fixing errors the error Could not symlink share/man/man3/SPI_connect.3 Another error that might show up is:

Error: Could not symlink lib/pkgconfig/libecpg.pc

sudo chown -R `whoami` /usr/local/lib/pkgconfig

brew link postgresql