fix set_subquery_pathlist()

Thanks to upper-planner pathification (3fc6e2d7f), subquery_planner
now produces a list of paths instead of a single plan. So tweak the
code to process all the paths.

XXX All the paths share the distribution, apparently. So maybe this
does not make much sense and we should pick one of the paths?

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 29c27c59eee6850bad849766339cd9b89916b264..d1233989f4c768f9162933af57d0091ac5f5f76a 100644 (file)
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -1661,6 +1661,7 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
        Relids          required_outer;
        pushdown_safety_info safetyInfo;
        double          tuple_fraction;
+       PlannerInfo *subroot;
 #ifdef XCP
        Distribution *distribution;
 #endif
@@ -1785,6 +1786,26 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
        rel->subplan_params = root->plan_params;
        root->plan_params = NIL;
 
+       /* For convenience. */
+       subroot = rel->subroot;
+
+       /* 
+        * Temporarily block ORDER BY in subqueries until we can add support 
+        * it in Postgres-XL without outputting incorrect results. Should
+        * do this only in normal processing mode though!
+     *
+     * The extra conditions below try to handle cases where an ORDER BY
+     * appears in a simple VIEW or INSERT SELECT.
+     */
+       if (IsUnderPostmaster &&
+               list_length(subquery->sortClause) > 1
+                               && (subroot->parent_root != root
+                               || (subroot->parent_root == root 
+                                       && (root->parse->commandType != CMD_SELECT
+                                               || (root->parse->commandType == CMD_SELECT
+                                                       && root->parse->hasWindowFuncs)))))
+               elog(ERROR, "Postgres-XL does not currently support ORDER BY in subqueries");
+
        /*
         * It's possible that constraint exclusion proved the subquery empty. If
         * so, it's desirable to produce an unadorned dummy path so that we will
@@ -1805,53 +1826,6 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
         */
        set_subquery_size_estimates(root, rel);
 
-       /* Generate appropriate path */
-#ifdef XCP
-       if (subroot->distribution && subroot->distribution->distributionExpr)
-       {
-               ListCell *lc;
-               /*
-                * The distribution expression from the subplan's tlist, but it should
-                * be from the rel, need conversion.
-                */
-               distribution = makeNode(Distribution);
-               distribution->distributionType = subroot->distribution->distributionType;
-               distribution->nodes = bms_copy(subroot->distribution->nodes);
-               distribution->restrictNodes = bms_copy(subroot->distribution->restrictNodes);
-               foreach(lc, rel->subplan->targetlist)
-               {
-                       TargetEntry *tle = (TargetEntry *) lfirst(lc);
-                       if (equal(tle->expr, subroot->distribution->distributionExpr))
-                       {
-                               distribution->distributionExpr = (Node *)
-                                               makeVarFromTargetEntry(rel->relid, tle);
-                               break;
-                       }
-               }
-       }
-       else
-               distribution = subroot->distribution;
-       add_path(rel, create_subqueryscan_path(root, rel, pathkeys, required_outer,
-                        distribution));
-
-       /* 
-        * Temporarily block ORDER BY in subqueries until we can add support 
-        * it in Postgres-XL without outputting incorrect results. Should
-        * do this only in normal processing mode though!
-     *
-     * The extra conditions below try to handle cases where an ORDER BY
-     * appears in a simple VIEW or INSERT SELECT.
-     */
-       if (IsUnderPostmaster &&
-               list_length(subquery->sortClause) > 1
-                               && (subroot->parent_root != root
-                               || (subroot->parent_root == root 
-                                       && (root->parse->commandType != CMD_SELECT
-                                               || (root->parse->commandType == CMD_SELECT
-                                                       && root->parse->hasWindowFuncs)))))
-               elog(ERROR, "Postgres-XL does not currently support ORDER BY in subqueries");
-#else
-
        /*
         * For each Path that subquery_planner produced, make a SubqueryScanPath
         * in the outer query.
@@ -1867,12 +1841,42 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
                                                                                         subpath->pathkeys,
                                                        make_tlist_from_pathtarget(subpath->pathtarget));
 
+               if (subroot->distribution && subroot->distribution->distributionExpr)
+               {
+                       ListCell *lc;
+
+                       /* FIXME Could we use pathtarget directly? */
+                       List *targetlist = make_tlist_from_pathtarget(subpath->pathtarget);
+
+                       /*
+                        * The distribution expression from the subplan's tlist, but it should
+                        * be from the rel, need conversion.
+                        */
+                       distribution = makeNode(Distribution);
+                       distribution->distributionType = subroot->distribution->distributionType;
+                       distribution->nodes = bms_copy(subroot->distribution->nodes);
+                       distribution->restrictNodes = bms_copy(subroot->distribution->restrictNodes);
+
+                       foreach(lc, targetlist)
+                       {
+                               TargetEntry *tle = (TargetEntry *) lfirst(lc);
+                               if (equal(tle->expr, subroot->distribution->distributionExpr))
+                               {
+                                       distribution->distributionExpr = (Node *)
+                                                       makeVarFromTargetEntry(rel->relid, tle);
+                                       break;
+                               }
+                       }
+               }
+               else
+                       distribution = subroot->distribution;
+
                /* Generate outer path using this subpath */
                add_path(rel, (Path *)
                                 create_subqueryscan_path(root, rel, subpath,
-                                                                                 pathkeys, required_outer));
+                                                                                 pathkeys, required_outer,
+                                                                                 distribution));
        }
-#endif
 }
 
 /*