> This is not wrong, or at least not obviously wrong. A full-table > indexscan is often slower than seqscan-and-sort. If the particular > case is wrong for you, you need to look at adjusting the planner's > cost parameters to match your environment. But you didn't provide any > evidence that the chosen plan is actually worse than the alternative > ...
I think I understand what Bob's getting at when he mentions blocking. The seqscan-and-sort would return the last record faster, but the indexscan returns the first record faster. If you're iterating through the records via a cursor, the indexscan behavior would be more desirable. You could get the initial rows back without waiting for all 130 million to be fetched and sorted.
In oracle, there is a first-rows vs. all-rows query hint for this sort of thing.
Yes, that's exactly what I mean. I've already tried your suggestion (set enable_seqscan to off) with no luck.