Hi,
On Mon, 2017-05-15 at 12:55 -0700, Ken Tanzer wrote:
> Hi. On a Centos 6.9 server (in the cloud with Rackspace), I'm wanting to
> install PGDG 9.6 alongside the already-running 9.2. After installing the
> 9.6 packages (and even before doing an initdb), I am no
> longer able to make a local connection to the 9.2 server. Instead I get
> the message:
>
> psql: could not connect to server: Connection refused
> Is the server running locally and accepting
> connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
>
> That socket file does not exist on the server. (And in fact, the
> /var/run/postgresql directory didn't exist before installing 9.6). When I
> configure 9.6 to use port 5433 and run it, it does create that socket for
> 5433. I tried creating such a socket manually for 5432, but that didn't
> seem to change anything.
>
> Any help in getting this working and/or pointing out what I'm missing would
> be great. I'm also confused conceptually about what is happening here.
> What is it that the installation (but not execution) of 9.6 does that's
> blocking the local 9.2 access? I'm guessing it's gotta be something in the
> RPM install scripts.
PGDG RPMs use alternatives method, to replace some binaries that can be used
across multiple PostgreSQL versions, and psql is one of them. When you install
9.6, 9.6's psql has higher priority than 9.2, so that one is used -- and 9.4+
are complied with a patch that changes default socket directory from /tmp to
/var/run/postgresql, and 9.2 is not aware of that.
Workarounds:
* You can connect to 9.2 using /usr/pgsql-9.2/bin/psql command. It knows the
old socket directory.
* Pass -h /tmp to 9.6's psql, so that it connects to 9.2 instance.
-HTH
Regards,
--
Devrim Gündüz
EnterpriseDB: http://www.enterprisedb.com
PostgreSQL Danışmanı/Consultant, Red Hat Certified Engineer
Twitter: @DevrimGunduz , @DevrimGunduzTR