* Is it safe to replace outerjoinpath with its fdw_outerpath the following way? I think that if the join relation represented by outerjoinpath has local conditions that can't be executed remotely, we have to keep outerjoinpath in the path tree; we will otherwise fail to execute the local conditions. No?
+ /* + * If either inner or outer path is a ForeignPath corresponding to + * a pushed down join, replace it with the fdw_outerpath, so that we + * maintain path for EPQ checks built entirely of local join + * strategies. + */ + if (IsA(joinpath->outerjoinpath, ForeignPath)) + { + ForeignPath *foreign_path; + foreign_path = (ForeignPath *)joinpath->outerjoinpath; + if (foreign_path->path.parent->reloptkind == RELOPT_JOINREL) + joinpath->outerjoinpath = foreign_path->fdw_outerpath; + }
all the conditions (local and remote) should be part of fdw_outerpath as well, since that's the alternate local path, which should produce (when converted to the plan) the same result as the foreign path. fdw_outerpath should be a local path set when paths for outerjoinpath->parent was being created. Am I missing something?
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Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company
