Set partitioned_rels appropriately when UNION ALL is used.

In most cases, this omission won't matter, because the appropriate
locks will have been acquired during parse/plan or by AcquireExecutorLocks.
But it's a bug all the same.

Report by Ashutosh Bapat.  Patch by me, reviewed by Amit Langote.

Discussion: http://postgr.es/m/CAFjFpRdHb_ZnoDTuBXqrudWXh3H1ibLkr6nHsCFT96fSK4DXtA@mail.gmail.com

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index f087ddb61db8ae75781b674ba8f9cafb37621346..4a82636734e9415aab262d8deb6ebfc743369328 100644 (file)
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -1287,13 +1287,34 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
        ListCell   *l;
        List       *partitioned_rels = NIL;
        RangeTblEntry *rte;
+       bool            build_partitioned_rels = false;
 
+       /*
+        * A plain relation will already have a PartitionedChildRelInfo if it is
+        * partitioned.  For a subquery RTE, no PartitionedChildRelInfo exists; we
+        * collect all partitioned_rels associated with any child.  (This assumes
+        * that we don't need to look through multiple levels of subquery RTEs; if
+        * we ever do, we could create a PartitionedChildRelInfo with the
+        * accumulated list of partitioned_rels which would then be found when
+        * populated our parent rel with paths.  For the present, that appears to
+        * be unnecessary.)
+        */
        rte = planner_rt_fetch(rel->relid, root);
-       if (rte->relkind == RELKIND_PARTITIONED_TABLE)
+       switch (rte->rtekind)
        {
-               partitioned_rels = get_partitioned_child_rels(root, rel->relid);
-               /* The root partitioned table is included as a child rel */
-               Assert(list_length(partitioned_rels) >= 1);
+               case RTE_RELATION:
+                       if (rte->relkind == RELKIND_PARTITIONED_TABLE)
+                       {
+                               partitioned_rels =
+                                       get_partitioned_child_rels(root, rel->relid);
+                               Assert(list_length(partitioned_rels) >= 1);
+                       }
+                       break;
+               case RTE_SUBQUERY:
+                       build_partitioned_rels = true;
+                       break;
+               default:
+                       elog(ERROR, "unexpcted rtekind: %d", (int) rte->rtekind);
        }
 
        /*
@@ -1306,6 +1327,19 @@ add_paths_to_append_rel(PlannerInfo *root, RelOptInfo *rel,
                RelOptInfo *childrel = lfirst(l);
                ListCell   *lcp;
 
+               /*
+                * If we need to build partitioned_rels, accumulate the partitioned
+                * rels for this child.
+                */
+               if (build_partitioned_rels)
+               {
+                       List       *cprels;
+
+                       cprels = get_partitioned_child_rels(root, childrel->relid);
+                       partitioned_rels = list_concat(partitioned_rels,
+                                                                                  list_copy(cprels));
+               }
+
                /*
                 * If child has an unparameterized cheapest-total path, add that to
                 * the unparameterized Append path we are constructing for the parent.

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 3e93eee6d8eb0e9130acce5f8e13ccd0a1f6bb7d..793242759d19335691664faf3a2838881e628f1f 100644 (file)
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6068,7 +6068,8 @@ plan_cluster_use_sort(Oid tableOid, Oid indexOid)
  *             Returns a list of the RT indexes of the partitioned child relations
  *             with rti as the root parent RT index.
  *
- * Note: Only call this function on RTEs known to be partitioned tables.
+ * Note: This function might get called even for range table entries that
+ * are not partitioned tables; in such a case, it will simply return NIL.
  */
 List *
 get_partitioned_child_rels(PlannerInfo *root, Index rti)
@@ -6087,8 +6088,5 @@ get_partitioned_child_rels(PlannerInfo *root, Index rti)
                }
        }
 
-       /* The root partitioned table is included as a child rel */
-       Assert(list_length(result) >= 1);
-
        return result;
 }