On Tue, Mar 24, 2020 at 10:08 PM Dmitry Dolgov <9erthali...@gmail.com> wrote: > > > On Wed, Mar 11, 2020 at 11:17:51AM +1300, David Rowley wrote: > > > > Yes, I was complaining that a ProjectionPath breaks the optimisation > > and I don't believe there's any reason that it should. > > > > I believe the way to make that work correctly requires paying > > attention to the Path's uniquekeys rather than what type of path it > > is. > > Thanks for the suggestion. As a result of the discussion I've modified > the patch, does it look similar to what you had in mind? > > In this version if all conditions are met and there are corresponding > unique keys, a new index skip scan path will be added to > unique_pathlists. In case if requested distinct clauses match with > unique keys, create_distinct_paths can choose this path without needen > to know what kind of path is it. Also unique_keys are passed through > ProjectionPath, so optimization for the example mentioned in this thread > before now should work (I've added one test for that). > > I haven't changed anything about UniqueKey structure itself (one of the > suggestions was about Expr instead of EquivalenceClass), but I believe > we need anyway to figure out how two existing imlementation (in this > patch and from [1]) of this idea can be connected. > > [1]: > https://www.postgresql.org/message-id/flat/CAKU4AWrwZMAL%3DuaFUDMf4WGOVkEL3ONbatqju9nSXTUucpp_pw%40mail.gmail.com
--- src/backend/nodes/outfuncs.c | 14 ++++++ src/backend/nodes/print.c | 39 +++++++++++++++ src/backend/optimizer/path/Makefile | 3 +- src/backend/optimizer/path/allpaths.c | 8 +++ src/backend/optimizer/path/indxpath.c | 41 ++++++++++++++++ src/backend/optimizer/path/pathkeys.c | 71 ++++++++++++++++++++++----- src/backend/optimizer/plan/planagg.c | 1 + src/backend/optimizer/plan/planmain.c | 1 + src/backend/optimizer/plan/planner.c | 37 +++++++++++++- src/backend/optimizer/util/pathnode.c | 46 +++++++++++++---- src/include/nodes/nodes.h | 1 + src/include/nodes/pathnodes.h | 19 +++++++ src/include/nodes/print.h | 1 + src/include/optimizer/pathnode.h | 2 + src/include/optimizer/paths.h | 11 +++++ 15 files changed, 272 insertions(+), 23 deletions(-) Seems like you forgot to add the uniquekey.c file in the v33-0001-Unique-key.patch. -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
