Re: [GENERAL] Help: Installing 9.6 breaks local connections to 9.2 onCentos 6.9

On 05/15/2017 01:10 PM, Devrim Gündüz wrote:
>
> 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.

That was where I was going until I saw this in the OP:

bash-4.1$ /usr/pgsql-9.2/bin/psql -p 5432
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"?


>
> * Pass -h /tmp to 9.6's psql, so that it connects to 9.2 instance.
>
> -HTH
>
> Regards,
>


--
Adrian Klaver
adrian.klaver@aklaver.com