On Fri, Aug 07, 2009 at 06:28:34PM -0400, Tom Lane wrote:
> David Fetter <david@fetter.org> writes:
> > I am not suggesting that this change be immediate, and it's not ivory
> > tower. It's just how everybody else does it.
>
> You keep saying that, and it's completely meaningless. What do you know
> about the development practices of Oracle, or DB2, or even Mysql?
When I was at Sybase, changes to the on disk structure were required to
provide code to do the migration. Nonetheless, at release time, the
migrate process was almost always discovered to be broken, sometimes even
before it was shipped to customers.
Of course, Sybase implemented its own complete filesystem layer on top of
raw partitions, so there was more scope to go wrong, especially since it
was possible to corrupt the on disk structure in subtle ways that would
not be discovered in normal operation but that would cause migration to
corrupt it still further.
In fairness, this is a very difficult problem to solve well and I expect
to rely on dump/load migrations for quite sometime.
-dg
--
David Gould daveg@sonic.net 510 536 1443 510 282 0869
If simplicity worked, the world would be overrun with insects.