Hadi Moshayedi <hadi@xxxxxxxxxxxxx> writes: > I am wondering why is it not using index-only-scan (which would use the > cache better) and instead it does a bitmap scan? Never experiment on an empty table and assume that the resulting plan is the same as you'd get on a large table. In this case, not only don't you have any meaningful amount of data loaded, but the planner can see that none of the table's pages are marked all-visible, meaning that the "index-only" scan would degrade to a regular indexscan, which is how it gets costed. And on a single-page table, an indexscan is going to have a hard time beating other alternatives. regards, tom lane
