fix grouping sets planning by removing XL changes from make_sort()

Commit 44fd89e213 enabled grouping sets, but planning of some queries
failed in fix_upper_expr. This was happening when the grouping sets
need multiple sort orders - in that case create_groupingsets_plan
builds additional Sort nodes (using make_sort_from_groupcols), but
the XL code in make_sort() got confused by this and ended up with
a RemoteSubplan with an empty targetlist.

Removing the XL optimization from make_sort() resolve the planning
issue, producing plans like this:

                     QUERY PLAN
    ---------------------------------------------
     GroupAggregate
       Group Key: a
       Sort Key: b
         Group Key: b
       ->  Remote Subquery Scan on all (dn1,dn2)
             ->  Sort
                   Sort Key: a
                   ->  Seq Scan on t1
    (8 rows)

Which seems correct.

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 2cab5c5308689c6e82e39861018f3bf109eb023d..8577bff7bf9b352ee5cc847f154b820c67bbf6ff 100644 (file)
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -5797,9 +5797,6 @@ make_sort(Plan *lefttree, int numCols,
 {
        Sort       *node = makeNode(Sort);
        Plan       *plan = &node->plan;
-#ifdef XCP
-       RemoteSubplan *pushdown;
-#endif
 
        plan->targetlist = lefttree->targetlist;
        plan->qual = NIL;
@@ -5811,84 +5808,6 @@ make_sort(Plan *lefttree, int numCols,
        node->collations = collations;
        node->nullsFirst = nullsFirst;
 
-#ifdef XCP
-       /*
-        * It does not makes sence to sort on one data node and then perform
-        * one-tape merge sort. So do not push sort down if there is single
-        * remote data node
-        */
-       pushdown = find_push_down_plan(lefttree, false);
-       if (pushdown)
-       {
-               /* If we already sort results, need to prepend new keys to existing */
-               /*
-                * It is not safe to share colum information.
-                * If another node will be pushed down the same RemoteSubplan column
-                * indexes may be modified and this would affect the Sort node
-                */
-               AttrNumber *newSortColIdx;
-               Oid        *newSortOperators;
-               Oid        *newCollations;
-               bool       *newNullsFirst;
-               int             newNumCols;
-               int             i, j;
-
-               /*
-                * Insert new sort node immediately below the pushdown plan
-                */
-               plan->lefttree = pushdown->scan.plan.lefttree;
-               pushdown->scan.plan.lefttree = plan;
-
-               newNumCols = numCols + (pushdown->sort ? pushdown->sort->numCols : 0);
-               newSortColIdx = (AttrNumber *) palloc(newNumCols * sizeof(AttrNumber));
-               newSortOperators = (Oid *) palloc(newNumCols * sizeof(Oid));
-               newCollations = (Oid *) palloc(newNumCols * sizeof(Oid));
-               newNullsFirst = (bool *) palloc(newNumCols * sizeof(bool));
-
-               /* Copy sort columns */
-               for (i = 0; i < numCols; i++)
-               {
-                       newSortColIdx[i] = sortColIdx[i];
-                       newSortOperators[i] = sortOperators[i];
-                       newCollations[i] = collations[i];
-                       newNullsFirst[i] = nullsFirst[i];
-               }
-
-               newNumCols = numCols;
-               if (pushdown->sort)
-               {
-                       /* Continue and copy old keys of the subplan which is now under the
-                        * sort */
-                       for (j = 0; j < pushdown->sort->numCols; j++)
-                               newNumCols = add_sort_column(pushdown->sort->sortColIdx[j],
-                                                                                        pushdown->sort->sortOperators[j],
-                                                                                        pushdown->sort->sortCollations[j],
-                                                                                        pushdown->sort->nullsFirst[j],
-                                                                                        newNumCols,
-                                                                                        newSortColIdx,
-                                                                                        newSortOperators,
-                                                                                        newCollations,
-                                                                                        newNullsFirst);
-               }
-               else
-               {
-                       /* Create simple sort object if does not exist */
-                       pushdown->sort = makeNode(SimpleSort);
-               }
-
-               pushdown->sort->numCols = newNumCols;
-               pushdown->sort->sortColIdx = newSortColIdx;
-               pushdown->sort->sortOperators = newSortOperators;
-               pushdown->sort->sortCollations = newCollations;
-               pushdown->sort->nullsFirst = newNullsFirst;
-
-               /*
-                * lefttree is not actually a Sort, but we hope it is not important and
-                * the result will be used as a generic Plan node.
-                */
-               return (Sort *) lefttree;
-       }
-#endif
        return node;
 }