On 7 Dec 2019, at 2:26am, Shawn Wagner <shawnw.mob...@gmail.com> wrote:
> The first one uses the index for all sorting, but the second one only uses it > for sorting a, not b. I feel like the descending sort could make use of the > index too, just reading the b sections backwards to get the right order. Is > there something I'm overlooking that would make this sort of optimization > impractical or otherwise a bad idea? Hmm. Try running ANALYZE and then doing the EXPLAIN QUERY PLAN lines again. But I think that without 'chunkiness' information (how many values columns a and b have) it would not be worth doing the complicated programming required for reverse-mini-scanning of that index. The programming is quite complicated and unless your index "b" is chunky it won't save you much time over the plan shown. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
