> Part of the answer, I think, is to make performance less reliant on good > optimization. In XSLT , the key() function goes a long way towards this: > by giving programmers a tool to control when indexes are built and used, > performance of many join constructs becomes much more predictable > > I’ve always felt that the anathema felt > in the database query community towards such constructs is misplaced – > alhough it’s great when optimizers are good enough that they aren’t needed, > I’ve seen programmers tearing their hair out trying to second-guess the > optimizer, and in such cases it’s not clear we’re doing programmers a > service. This is indeed somewhat funny.
See the original post:
Requirements on Optimizers [was ANSWERS to "What's
wrong with XQuery" question]
