Re: Overhead cost of Serializable Snapshot Isolation

On tis, 2011-10-11 at 21:50 +0100, Simon Riggs wrote:
> I'm keen to ensure people enjoy the possibility of upgrading to the
> latest release. The continual need to retest applications mean that
> very few users upgrade quickly or with anywhere near the frequency
> with which we put out new releases. What is the point of rushing out
> software that nobody can use? pg_upgrade doesn't change your
> applications, so there isn't a fast path to upgrade in the way you
> seem to think.

This is a valid concern, which I share, but I think adding a few
configuration parameters of the nature, "this setting really means what
this setting meant in the old release" is only the tip of the iceberg.
Ensuring full compatibility between major releases would require an
extraordinary amount of effort, including a regression test suite that
would be orders of magnitude larger than what we currently have. I
frankly don't see the resources to do that.

The workaround strategy is that we maintain backbranches, so that users
are not forced to upgrade to incompatible releases.

Actually, I'm currently personally more concerned about the breakage we
introduce in minor releases. We'd need to solve that problem before we
can even begin to think about dealing with the major release issue.