On Wed, 2006-05-03 at 17:48, John D. Burger wrote: > Csaba Nagy wrote: > > > select * from table order by col_1; > > > > Isn't it supposed to choose the index scan at least when > > enable_seqscan=off ? Even if it is indeed not faster to do the index > > scan than seqscan+sort. > > I think because you've asked for every row, it's going to have to scan > the whole table anyway, to determine MVCC "liveness" of the rows > (sorry, dunno what the correct word is). But I also asked for _ordered_ results, which the seq scan is not covering, but the index does... and I specifically disabled sequential scan. That means the planner is not even considering the primary key index, and I would like to know why... Actually this is a problem for me in a more complex query, which also needs this table ordered by that column, and it results in the same plan fragment with sequential scan + sort. Thanks, Csaba.
