RULES vs. COST

Hi folks. I'm trying to gather opinions and guesses about Oracle7's optimization options, and what currently is the best setup.

My understanding is this: Oracle has always used a RULES-based system. Oracle7 now has both a COST-based as well as RULES-based system.

These are what I have heard...and please feel free to shoot holes in them if they're not right:

• RULES-based optimization will not be supported by Oracle in the next few years.
• The current COST-based system is not working 100%, ie. the optimal execution plan is not always chosen, and there are rare instances where incorrect data is returned.
• When the RULES-based system is no longer supported by Oracle, they will have made modifications to the COST-based system, so that the parser will choose the correct path, no matter how the query was originally optimized.

I was wondering if anyone had any opinions on which is currently the best setup (RULES vs. COST), based on any experience. I keep hearing adament defenses of both systems, so I figure the more the merrier. :)

Thanks for any ideas, thoughts, opinions, etc, Ed Received on Wed Feb 08 1995 - 18:35:52 CET