Re: When are index scans used over seq scans?

John A Meinel wrote:
> I believe the problem is that postgres doesn't recognize how restrictive
> a date-range is unless it uses constants.

And it does when using BETWEEN with int for example? Impressive. :-)

> select blah from du WHERE time between '2004-10-10' and '2004-10-15';
> Will properly use the index, because it realizes it only returns a few
> rows.

Correct, it does.

> Probably you should try to find out the status of multi-table
> selectivity. It was discussed in the last couple of months.

I can't find the posts you are refering to. What is the priciple of
multi-table selectivity?

Your explanation sounds very plausible.. I don't mind changing the
cpu_tuple_cost before running BETWEEN with timestamps, they are easy
enough to spot.

Thanks,

--
Richard van den Berg, CISSP
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