Re: Quality and Performance

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Joshua D. Drake wrote:
>> Well I think that we do take performance into account. I agree
>> that we should *never* have a regression in performance from release
>> to release, which is what I believe has inspired this thread.

> Hmm.  I have developed several features that have driven performance
> down.

Even changes that are not feature additions but intended solely to
improve performance may have corner cases where they are losses rather
than wins.  I think "*never* have a regression in performance" is not
only pie-in-the-sky but would be a bad policy to adopt, because it
would mean for instance that we couldn't intentionally optimize common
cases at the expense of uncommon ones.

However, I think everybody agrees that getting blindsided by unexpected
performance dropoffs is a bad thing.  We really need to reinstitute
the sort of daily (or near-daily) performance tracking that Mark Wong
used to be doing, and extend it to cover a wider variety of test cases
than just DBT-2.  As an example, I'll bet that this issue of operator
lookup speed would never have been visible at all in DBT-2.
        regards, tom lane