diff options
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 41 | ||||
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 46 | ||||
| -rw-r--r-- | src/include/optimizer/planmain.h | 2 |
3 files changed, 65 insertions, 24 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index bf7c557da42..309f27ca856 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -1181,33 +1181,50 @@ postgresGetForeignPlan(PlannerInfo *root, /* * Ensure that the outer plan produces a tuple whose descriptor - * matches our scan tuple slot. This is safe because all scans and - * joins support projection, so we never need to insert a Result node. - * Also, remove the local conditions from outer plan's quals, lest - * they will be evaluated twice, once by the local plan and once by - * the scan. + * matches our scan tuple slot. Also, remove the local conditions + * from outer plan's quals, lest they be evaluated twice, once by the + * local plan and once by the scan. */ if (outer_plan) { ListCell *lc; - outer_plan->targetlist = fdw_scan_tlist; - + /* + * First, update the plan's qual list if possible. In some cases + * the quals might be enforced below the topmost plan level, in + * which case we'll fail to remove them; it's not worth working + * harder than this. + */ foreach(lc, local_exprs) { - Join *join_plan = (Join *) outer_plan; Node *qual = lfirst(lc); outer_plan->qual = list_delete(outer_plan->qual, qual); /* * For an inner join the local conditions of foreign scan plan - * can be part of the joinquals as well. + * can be part of the joinquals as well. (They might also be + * in the mergequals or hashquals, but we can't touch those + * without breaking the plan.) */ - if (join_plan->jointype == JOIN_INNER) - join_plan->joinqual = list_delete(join_plan->joinqual, - qual); + if (IsA(outer_plan, NestLoop) || + IsA(outer_plan, MergeJoin) || + IsA(outer_plan, HashJoin)) + { + Join *join_plan = (Join *) outer_plan; + + if (join_plan->jointype == JOIN_INNER) + join_plan->joinqual = list_delete(join_plan->joinqual, + qual); + } } + + /* + * Now fix the subplan's tlist --- this might result in inserting + * a Result node atop the plan tree. + */ + outer_plan = change_plan_targetlist(outer_plan, fdw_scan_tlist, + best_path->path.parallel_safe); } } diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index b79aa3fe390..9c16065c154 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -1252,19 +1252,10 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path, int flags) } } + /* Use change_plan_targetlist in case we need to insert a Result node */ if (newitems || best_path->umethod == UNIQUE_PATH_SORT) - { - /* - * If the top plan node can't do projections and its existing target - * list isn't already what we need, we need to add a Result node to - * help it along. - */ - if (!is_projection_capable_plan(subplan) && - !tlist_same_exprs(newtlist, subplan->targetlist)) - subplan = inject_projection_plan(subplan, newtlist); - else - subplan->targetlist = newtlist; - } + subplan = change_plan_targetlist(subplan, newtlist, + best_path->path.parallel_safe); /* * Build control information showing which subplan output columns are to @@ -1506,6 +1497,37 @@ inject_projection_plan(Plan *subplan, List *tlist) } /* + * change_plan_targetlist + * Externally available wrapper for inject_projection_plan. + * + * This is meant for use by FDW plan-generation functions, which might + * want to adjust the tlist computed by some subplan tree. In general, + * a Result node is needed to compute the new tlist, but we can optimize + * some cases. + * + * In most cases, tlist_parallel_safe can just be passed as the parallel_safe + * flag of the FDW's own Path node. (It's not actually used in this branch.) + */ +Plan * +change_plan_targetlist(Plan *subplan, List *tlist, bool tlist_parallel_safe) +{ + /* + * If the top plan node can't do projections and its existing target list + * isn't already what we need, we need to add a Result node to help it + * along. + */ + if (!is_projection_capable_plan(subplan) && + !tlist_same_exprs(tlist, subplan->targetlist)) + subplan = inject_projection_plan(subplan, tlist); + else + { + /* Else we can just replace the plan node's tlist */ + subplan->targetlist = tlist; + } + return subplan; +} + +/* * create_sort_plan * * Create a Sort plan for 'best_path' and (recursively) plans diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h index 4fbb6cc3e7e..b046ea1285b 100644 --- a/src/include/optimizer/planmain.h +++ b/src/include/optimizer/planmain.h @@ -52,6 +52,8 @@ extern ForeignScan *make_foreignscan(List *qptlist, List *qpqual, Index scanrelid, List *fdw_exprs, List *fdw_private, List *fdw_scan_tlist, List *fdw_recheck_quals, Plan *outer_plan); +extern Plan *change_plan_targetlist(Plan *subplan, List *tlist, + bool tlist_parallel_safe); extern Plan *materialize_finished_plan(Plan *subplan); extern bool is_projection_capable_path(Path *path); extern bool is_projection_capable_plan(Plan *plan); |