> I actually do get perfect query plans without any stats, because
> our indexes are perfectly matched to our statements, and in two
> cases we tuned the sql appropriately (2 of >200 statements with
> Informix optimizer hints). For such a condition you actually
> want a rule based optimizer. The current default values during
> create table are more or less chosen to give exactly this "rule
> based" behavior. The trouble is, that after the first implicitly
> created stats, the optimizer goes completely bananas, because
> now he thinks that one table has 1000 (the default) rows (it
> actually has 10000000), but the other has 100000 and the optimizer
> now knows that and chooses a different plan. And just because
> you copy a few rows ?
Oh, that is interesting. You didn't explicitly ask for stats, but got
them anyway and that caused a problem.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
