Bruce Momjian wrote:
>
> OK, yes, sequential scan _can_ be as slow as index scan, but sometimes
> it is faster. Can you provide reasoning why index scan should be
> preferred, other than the admin created it, which I already addressed?
If you have a choice between two or more sub-plans, similar in cost, say within
20% of one another. Choosing a plan which uses an index has a chance of
improved performance if the estimates are wrong where as choosing the
sequential scan will always have the full cost.