On Sun, Feb 04, 2018 at 05:28:52PM +0200, Mariel Cherkassky wrote: > I read those two links and I dont think that they are relevant because : 1 > 1)I didnt do any join. > 2)I used a where clause in my select https://www.postgresql.org/docs/current/static/ddl-partitioning.html |The following caveats apply to constraint exclusion: | Constraint exclusion only works when the query's WHERE clause contains |constants (or externally supplied parameters). For example, a comparison |against a non-immutable function such as CURRENT_TIMESTAMP cannot be optimized, |since the planner cannot know which partition the function value might fall |into at run time. [..] The issue is with the comparison between function call to to_date() compared with constant - that doesn't allow constraint exclusion as currently implemented. Justin 2018-02-04 16:54 GMT+02:00 Andreas Kretschmer <andreas@xxxxxxxxxxxxxxx>: > > Am 04.02.2018 um 13:19 schrieb Mariel Cherkassky: > > > > > > > >> I checked the plan of the next query : > > > >> explain select count(*) from log_full where end_date between > > > >> to_date('2017/12/03','YY/MM/DD') and to_date('2017/12/03','YY/MM/ > > DD'); > > > >> > > > >> > > > > can you rewrite the query to > > > > > > > > ... where end_date between '2017/12/03' and '2017/12/03' > > > > > > > > maybe the planner should be smart enough to do that for you, but obvously > > > > he can't. So it's a workaround, but it seems to solve the problem.
