On 1 March 2012 12:45, Marcin Mirosław <mar...@mejor.pl> wrote: > Hello, > my example query (and explain) is: > $ explain SELECT count(*) from (select * from users_profile order by id) > u_p; > QUERY PLAN > --------------------------------------------------------------------------- > Aggregate (cost=1.06..1.07 rows=1 width=0) > -> Sort (cost=1.03..1.03 rows=2 width=572) > Sort Key: users_profile.id > -> Seq Scan on users_profile (cost=0.00..1.02 rows=2 width=572) > (4 rows) > > Meseems "order by id" can be ignored by planner. It should speed up > query without side effect. I know the query should be fixed but this is > real and simplified query from real application. > Does postgresql team think ppostgres should be smarter than user and fix > user queries? If answer is positive please treat this as "feature request". > Thank you and regards, > Marcin. > > If you have only 2 rows in the table, then the plan really doesn't matter too much. Sorting two rows would be really fast :)
Try to check it with 10k rows. regards Szymon
