Re: Revisiting default_statistics_target

On Fri, 22 May 2009, Greg Sabino Mullane wrote:

>> The bump from 10 to 100 was supported by microbenchmarks that suggested it
>> would be tolerable.
>
> No, the 10 to 100 was supported by years of people working in the field who
> routinely did that adjustment (and >100) and saw great gains.

No one is suggesting the increase isn't important to people running many
common workloads. The question the smaller benchmarks tried to answer is
whether it was likely to detune anything else as a penalty for improving
that situation. The comments you made here can get turned right around at
you: if increasing the value in the field is sufficient to help out those
that need it, why should the project at large accept any significant
penalty that could apply to everyone just to help that subset?

Would you be happy with 8.4 going out the door if there really turns out
to be a 15% penalty for other use cases by this change? That's a PR
nightmare waiting to happen, and the main reason I wanted to bring this up
here with some additional details as soon as Jignesh's slides went
public--so everyone here is aware of what's going on before this bit of
news gets picked up anywhere else.

Hopefully whatever is happening to dbt2 will turn out to be a quirk not
worth worrying about. What if it turns out to be repeatable and expected
to impact people in the field though? I hope you'd recognize that your
use case is no more privileged to trump other people's than the changes
that would be good for DW users, but not anyone else, that you were just
making critical comments about.

Anyway, thanks to Stephen for concisely clarifying the position I was
trying to present here, which is quite different from the one you were
arguing against.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD