I was going to update my postgresql from 10 to 12, using homebrew.

What I did:

brew uninstall postgresql@10
brew install postgresql@12

I got the server running after this with brew services (but stopped it before trying pg_upgrade).

Then comes the problem. I got a db in the directory /opt/homebrew/var/postgresql@10/ that I wanted to move to the new postgresql directory /opt/homebrew/var/postgresql@12/.

So I used the command:

pg_upgrade -b /opt/homebrew/var/postgresql@10 -B /opt/homebrew/var/postgresql@12 -d /opt/homebrew/var/postgresql@10 -D /opt/homebrew/var/postgresql@12

which resulted in failure with the explanation:

check for "/opt/homebrew/var/postgresql@10/postgres" failed: No such file or directory Failure, exiting

There is no folder named “postgres” in that directory but I don’t believe it should be reading the documentation, and looking at others’ example of how pg_upgrade is used, like this gist for example.

There DO EXIST a directory on the path to a bunch of files and folders which seem to be the same as in the documentation link above.

I have scoured the web for someone having the same problem without any luck. Do someone know what this issue might be, or can help me troubleshoot it further?

Thanks