Re: Versioning policy and pg_upgrade

On Fri, Jan 28, 2011 at 9:50 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> 1. This is the wrong mailing list for this discussion.
>
> It's a web site patch. Where should it be posted?

Oh, sorry. I thought we were talking about the docs.

>> 2. I think the whole point here is that we've had a policy change: we
>> are now making an effort to maintain backward compatibility for data
>> files, though not for system tables.  The docs should reflect that.
>>
>> Maybe something like:
>>
>> Major releases usually change the format of system tables.  These
>> changes are often complex, so we do not maintain backward
>> compatibility.  Our dump and reload tools do maintain backward
>> compatibility and are the most reliable way to perform a major version
>> upgrade.  Some major releases also change the internal format of data
>> files; however, in recent releases, we have made an attempt to
>> minimize such changes.  In cases where the data file formats have not
>> changed, pg_upgrade can also be used for major upgrade version
>> upgrades; this is typically much faster than a dump and reload.
>
> That seems quite detailed for the web site.  If we want that I think we
> should add those details to the pg_upgrade manual page.  Some of that is
> already there.

It's not that much more than you wrote, and it has the redeeming value
of being accurate...

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company