Craig A. James wrote:
2. Hints
a) On a aesthetic/theoretical level, hints suck. They're ugly and rude
b) On a practical level, introducing hints will cause short- and
long-term problems
c) Hints would help DBAs solve urgent problems for which there is no
other solution
Pretty good summary!
Maybe there should be a 2d), 2e) and 2f).
2d) Hints will damage the ongoing development of the optimizer by
reducing or eliminating test cases for its improvement.
2e) Hints will divert developer resource away from ongoing development
of the optimizer.
2f) Hints may demoralize the developer community - many of whom will
have been attracted to Postgres precisely because this was a realm where
crude solutions were discouraged.
I understand that these points may seem a bit 'feel-good' and intangible
- especially for the DBA's moving to Pg from Oracle, but I think they
illustrate the mindset of the Postgres developer community, and the
developer community is, after all - the primary reason why Pg is such a
good product.
Of course - if we can find a way to define 'hint like' functionality
that is more in keeping with the 'Postgres way' (e.g. some of the
relation level statistical additions as discussed), then some of 2d-2f)
need not apply.
Best wishes
Mark
