Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote: > (2019/03/01 20:16), Antonin Houska wrote: > > Etsuro Fujita<fujita.ets...@lab.ntt.co.jp> wrote: > > >> Conversely, it appears that add_foreign_ordered_paths() added by the > >> patchset > >> would generate such pre-sorted paths *redundantly* when the input_rel is > >> the > >> final scan/join relation. Will look into that. > > > > Currently I have no idea how to check the plan created by FDW at the > > UPPERREL_ORDERED stage, except for removing the sort from the > > UPPERREL_GROUP_AGG stage as I proposed here: > > > > https://www.postgresql.org/message-id/11807.1549564431%40localhost > > I don't understand your words "how to check the plan created by FDW". Could > you elaborate on that a bit more?
I meant that I don't know how to verify that the plan that sends the ORDER BY clause to the remote server was created at the UPPERREL_ORDERED and not at UPPERREL_GROUP_AGG. However if the ORDER BY clause really should not be added at the UPPERREL_GROUP_AGG stage and if we ensure that it no longer happens, then mere presence of ORDER BY in the (remote) plan means that the UPPERREL_ORDERED stage works fine. -- Antonin Houska https://www.cybertec-postgresql.com
