+1 for fixing this in the backend code rather than FDW code. Thanks, Richard, for working on this. The patch looks good to me at a glance.
On Tue, Apr 25, 2023 at 3:36 PM Richard Guo <guofengli...@gmail.com> wrote: > > On Fri, Apr 14, 2023 at 8:51 PM Etsuro Fujita <etsuro.fuj...@gmail.com> > wrote: > >> I think that the root cause for this issue would be in the >> create_scan_plan handling of pseudoconstant quals when creating a >> foreign-join (or custom-join) plan. > > > Yes exactly. In create_scan_plan, we are supposed to extract all the > pseudoconstant clauses and use them as one-time quals in a gating Result > node. Currently we check against rel->baserestrictinfo and ppi_clauses > for the pseudoconstant clauses. But for scans of foreign joins, we do > not have any restriction clauses in these places and thus the gating > Result node as well as the pseudoconstant clauses would just be lost. > > I looked at Nishant's patch. IIUC it treats the pseudoconstant clauses > as local conditions. While it can fix the wrong results issue, I think > maybe it's better to still treat the pseudoconstant clauses as one-time > quals in a gating node. So I wonder if we can store the restriction > clauses for foreign joins in ForeignPath, just as what we do for normal > JoinPath, and then check against them for pseudoconstant clauses in > create_scan_plan, something like attached. > > BTW, while going through the codes I noticed one place in > add_foreign_final_paths that uses NULL for List *. I changed it to NIL. > > Thanks > Richard > -- -- Thanks & Regards, Suraj kharage, edbpostgres.com
