On Wed, Nov 21, 2012 at 5:42 AM, Kevin Grittner
<kgrittn@mail.com> wrote:
It's a tough problem. Disguising and not documenting the available
optimizer hints leads to more reports on where the optimizer should
be smarter, and has spurred optimizer improvements. ...
Regarding the above-mentioned benefits we would stand to lose by
having clear and documented hints, perhaps we could occasionally
solicit input on where people are finding hints useful to get ideas
on where we might want to improve the optimizer. As far as worrying
about people using hints to force a plan which is sub-optimal --
isn't that getting into nanny mode a bit too much?
Toward that end, the hint documentation (which is almost always viewed as HTML) could be prefaced by a strong suggestion to post performance questions in this group first, with links to the "subscribe" page and the "how to report performance problems" FAQ. The hint documentation could even be minimalistic; suggest to developers that they should post their problematic queries here before resorting to hints. That would give the experts an opportunity to provide the normal advice. The correct hint syntax would be suggested only when all other avenues failed.
Craig James
-Kevin