Re: network protocol and compatibility question - Mailing list pgsql-general

From Steve Atkins
Subject Re: network protocol and compatibility question
Date
Msg-id AEB076CF-BDFA-4DA1-A864-C677BAD3C4A4@blighty.com
Whole thread Raw
In response to network protocol and compatibility question  (Joek Hondius <jhondius@rem.nl>)
List pgsql-general
On Dec 9, 2013, at 2:39 AM, Joek Hondius <jhondius@rem.nl> wrote:

> Hi All,
>
> We have been running our product on PostgreSQL for quite some time now. Started out with 7.0
>
> I have this situation where i want to migrate my (many) PostgreSQL 8.3 databases to a new server running 9.2
> In my case this is not a problem for schema and data.
> But i do not want to update the client's drivers if i don't need to right now, but prefer to do that in future
updates.
>
> Reason is we are moving to new server infrastructure and want to go 9.2,
> but the  3rd party making the database driver for our legacy product has issues.
> This will otherwise keep us from moving to better/supported version.
> (insert legacy headache here)
>
> I found that the pgsql network protocol spec has not changed between 8.3 and 9.2.

It's backwards compatible to at least 8.3.

>
> Can i use my 8.3 clients on 9.2 servers since the protocol has not changed and the database schema remains the same?
> I would think yes, i will test but it would be best if backed by some kind of theorethical rationale.

The low level network protocol is compatible, but the system tables have changed. If your
database driver provides any sort of schema metadata to your app, or uses that itself,
then it may fail ungracefully. Without knowing more about your app and the database
access library it uses it's hard to say more than that.

> Any alternatives?
> Can i put pgBouncer 9.2 in front of a 8.3 server for example?

That won't have any effect on any issues you might see.

Cheers,
  Steve



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