Re: Database upgrading: upgrade server first or client first?

On 4/30/2012 1:34 PM, roy hills wrote:
> I'm running a postgresql 8.1 database on a single server which is
> queried from a number of client systems.
> Both server and clients are running Debian Linux.
>
> I need to upgrade from 8.1 to 8.3, but it's difficult for me to upgrade
> everything at once. Is it possible to
> run different versions of the client and server, and if so is it better
> to upgrade the client first or the server first?
>
> When I say "the client", I mean the psql client and the libpq library (I
> actually use Perl DBI, but I think that ends
> up calling functions in libpq).
>
> My gut feeling is that later versions of the client should detect and
> work with earlier versions of the server, so
> I should upgrade the clients first. But I can't see anything definitive
> on this.
>
> Any advice or pointers to FAQ items that I've missed would be appreciated.
>

The client (libpq.dll) is remarkably compatible. I've used old client's
on new server's and visa-versa, and only had one problem.

The new 9 server supports an application_name property in the connect
string, which I have started using, and the old client didnt like it.
The client side was a really old version, I'm not even sure what it was,
this is the first time I've updated it in a while. When I sent out my
new program I sent along the new PG 9 libpq along with it.

In my case, I have updated the server several times and never updated
the client till now.

-Andy