Re: Cost-based Optimizer
Date: 1996/02/06
Message-ID: <4f8e66$h46_at_lal.interserv.net>#1/1
> alc_at_nyx (Alain Cheong Chun Lin) writes:
> some feedback from people who are using cost-based. Is it better ? Can we
> move to cost-based blindfolded ? Are there any situations where cost-based is
> not recommended ?
>>>>
We're running Oracle 7.0.15 and default to rule-based on advice from the VAR we got our app. from. We
use cost-based with hints on an exception basis. We've been warned that some of our app's batch
processes give incorrect results with cost-based (apparently it can goof up parsing of some SQL). Also, if
you haven't run ANALYZE on a table you'll get a really bad plan. When I've TRUNCATEd a table the
ANALYZE statistics on it have gone away, so I have to do ANALYZE again when I load it. On the other
hand ANALYZE using the faster ESTIMATE method seems to be adequate.
- Paul de Anugera, City of Seattle HRIS Project