Re: Psql: could not connect to server: No such file or directory

SAMMY CRISWELL <Sammy_R_Criswell@raytheon.com> writes:
> I am preparing to upgrade my pqsl server from 9.3.5 to 9.6.12. I have installed the 9.6 rpm onto the server that has
9.3.5running. Postgres is still running 9.3.5 on that server, but when I try to run psql I get the following message. 

> "psql: could not connect to server: No such file or directory
>         Is the server running locally and accepting
>         connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?"
> The database is still running and working I just can't use any of the client commands like psql, pg_dump....
> And there is no "/var/run/postgresql/.s.PGSQL.5432" file.

What you've probably run into here is that some packagers build Postgres
to put the server's socket file into /tmp, while others build it to put
the socket into /var/run/postgresql/ or some similar path.  Likely,
you are now using a new version of libpq.so that expects the latter
while your server is still doing the former.  You can override libpq's
default with "-h /tmp" or equivalent in order to connect.

            regards, tom lane