Ian Lance Taylor <ian@airs.com> writes:
> It is desirable to have some reasonable mechanism for changing the
> schema without requiring data to be dumped and reloaded. Otherwise it
> is very difficult to upgrade a system which needs to be up 24/7, such
> as many web sites today.
> It is not acceptable for eBay to shut down their system for even just
> a few hours for maintenance. Shouldn't it be possible for eBay to run
> on top of Postgres?
What's that got to do with the argument at hand? On-the-fly schema
changes aren't free either; at the very least you have to lock down the
tables involved while you change them. When the change cascades across
multiple tables and functions (if it doesn't, this feature is hardly
of any use!), ISTM you still end up shutting down your operation for as
long as it takes to do the changes.
regards, tom lane