From 51d152f18e124cc07c293756cc16014ba218b2df Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Wed, 23 Dec 2015 13:39:42 -0500 Subject: [PATCH] Change Gather not to use a physical tlist. This should have been part of the original commit, but was missed. Pushing data between processes is expensive, so we definitely want to project away unneeded columns here, just as we do for other nodes like Sort and Hash that care about the volume of data. --- src/backend/optimizer/plan/createplan.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 32f903d8dc..01209aa328 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -558,7 +558,8 @@ use_physical_tlist(PlannerInfo *root, RelOptInfo *rel) * If the plan node immediately above a scan would prefer to get only * needed Vars and not a physical tlist, it must call this routine to * undo the decision made by use_physical_tlist(). Currently, Hash, Sort, - * and Material nodes want this, so they don't have to store useless columns. + * Material, and Gather nodes want this, so they don't have to store or + * transfer useless columns. */ static void disuse_physical_tlist(PlannerInfo *root, Plan *plan, Path *path) @@ -1123,6 +1124,8 @@ create_gather_plan(PlannerInfo *root, GatherPath *best_path) subplan = create_plan_recurse(root, best_path->subpath); + disuse_physical_tlist(root, subplan, best_path->subpath); + gather_plan = make_gather(subplan->targetlist, NIL, best_path->num_workers,