> On Wed, Jul 10, 2019 at 4:52 PM Floris Van Nee <florisvan...@optiver.com> > wrote: > > > Thanks for testing! Could you provide a test case to show what exactly is > > the > > problem? > > create table a (a int, b int, c int); > insert into a (select vs, ks, 10 from generate_series(1,5) vs, > generate_series(1, 10000) ks); > create index on a (a,b); > analyze a; > > set enable_indexskipscan=1; // setting this to 0 yields different results > set random_page_cost=1; > explain SELECT DISTINCT ON (a) a,b FROM a; > > BEGIN; > DECLARE c SCROLL CURSOR FOR SELECT DISTINCT ON (a) a,b FROM a; > > FETCH FROM c; > FETCH BACKWARD FROM c; > > FETCH 6 FROM c; > FETCH BACKWARD 6 FROM c; > > FETCH 6 FROM c; > FETCH BACKWARD 6 FROM c; > > END;
Ok, give me a moment, I'll check.
