Arnau <arnaulist@xxxxxxxxxxxxxxxxxx> writes: > I have done the same tests on 8.1.0. Bitmap scans are a totally different animal that doesn't exist in 7.4. A plain indexscan, such as 7.4 knows about, is generally not effective for fetching more than a percent or two of the table. The crossover point for a bitmap scan is much higher (don't know exactly, but probably something like 30-50%). regards, tom lane
