If the inputs of a UNION/INTERSECT/EXCEPT construct all agree on the
authorTom Lane <tgl@sss.pgh.pa.us>
Mon, 12 Nov 2001 20:04:20 +0000 (20:04 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Mon, 12 Nov 2001 20:04:20 +0000 (20:04 +0000)
typmod of a particular column, mark the output with that same typmod,
not -1 as formerly.  -1 is still used if there is any disagreement.
Part of response to bug#513.

src/backend/optimizer/prep/prepunion.c

index 888edf578f0d139eed3a425c949a1438db6f60fe..03c06b65da770f96d6696584d0ae6a3329b779c6 100644 (file)
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.68 2001/10/28 06:25:46 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.69 2001/11/12 20:04:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,6 +63,7 @@ static List *generate_setop_tlist(List *colTypes, int flag,
                     bool hack_constants,
                     List *input_tlist,
                     List *refnames_tlist);
+static void merge_tlist_typmods(List *tlist, List *planlist);
 static bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
 static Node *adjust_inherited_attrs_mutator(Node *node,
                               adjust_inherited_attrs_context *context);
@@ -204,6 +205,7 @@ generate_union_plan(SetOperationStmt *op, Query *parse,
                    List *refnames_tlist)
 {
    List       *planlist;
+   List       *tlist;
    Plan       *plan;
 
    /*
@@ -218,18 +220,21 @@ generate_union_plan(SetOperationStmt *op, Query *parse,
                                            op, refnames_tlist));
 
    /*
-    * Append the child results together.
+    * Generate tlist for Append plan node.
     *
     * The tlist for an Append plan isn't important as far as the Append is
     * concerned, but we must make it look real anyway for the benefit of
     * the next plan level up.
     */
-   plan = (Plan *)
-       make_append(planlist,
-                   false,
-                   generate_setop_tlist(op->colTypes, -1, false,
+   tlist = generate_setop_tlist(op->colTypes, -1, false,
                                 ((Plan *) lfirst(planlist))->targetlist,
-                                        refnames_tlist));
+                                refnames_tlist);
+   merge_tlist_typmods(tlist, planlist);
+
+   /*
+    * Append the child results together.
+    */
+   plan = (Plan *) make_append(planlist, false, tlist);
 
    /*
     * For UNION ALL, we just need the Append plan.  For UNION, need to
@@ -237,10 +242,9 @@ generate_union_plan(SetOperationStmt *op, Query *parse,
     */
    if (!op->all)
    {
-       List       *tlist,
-                  *sortList;
+       List       *sortList;
 
-       tlist = new_unsorted_tlist(plan->targetlist);
+       tlist = new_unsorted_tlist(tlist);
        sortList = addAllTargetsToSortList(NIL, tlist);
        plan = make_sortplan(parse, tlist, plan, sortList);
        plan = (Plan *) make_unique(tlist, plan, copyObject(sortList));
@@ -259,7 +263,8 @@ generate_nonunion_plan(SetOperationStmt *op, Query *parse,
               *rplan,
               *plan;
    List       *tlist,
-              *sortList;
+              *sortList,
+              *planlist;
    SetOpCmd    cmd;
 
    /* Recurse on children, ensuring their outputs are marked */
@@ -269,9 +274,10 @@ generate_nonunion_plan(SetOperationStmt *op, Query *parse,
    rplan = recurse_set_operations(op->rarg, parse,
                                   op->colTypes, false, 1,
                                   refnames_tlist);
+   planlist = makeList2(lplan, rplan);
 
    /*
-    * Append the child results together.
+    * Generate tlist for Append plan node.
     *
     * The tlist for an Append plan isn't important as far as the Append is
     * concerned, but we must make it look real anyway for the benefit of
@@ -279,18 +285,21 @@ generate_nonunion_plan(SetOperationStmt *op, Query *parse,
     * flag column is shown as a variable not a constant, else setrefs.c
     * will get confused.
     */
-   plan = (Plan *)
-       make_append(makeList2(lplan, rplan),
-                   false,
-                   generate_setop_tlist(op->colTypes, 2, false,
-                                        lplan->targetlist,
-                                        refnames_tlist));
+   tlist = generate_setop_tlist(op->colTypes, 2, false,
+                                lplan->targetlist,
+                                refnames_tlist);
+   merge_tlist_typmods(tlist, planlist);
+
+   /*
+    * Append the child results together.
+    */
+   plan = (Plan *) make_append(planlist, false, tlist);
 
    /*
     * Sort the child results, then add a SetOp plan node to generate the
     * correct output.
     */
-   tlist = new_unsorted_tlist(plan->targetlist);
+   tlist = new_unsorted_tlist(tlist);
    sortList = addAllTargetsToSortList(NIL, tlist);
    plan = make_sortplan(parse, tlist, plan, sortList);
    switch (op->op)
@@ -332,9 +341,11 @@ recurse_union_children(Node *setOp, Query *parse,
        {
            /* Same UNION, so fold children into parent's subplan list */
            return nconc(recurse_union_children(op->larg, parse,
-                                             top_union, refnames_tlist),
+                                               top_union,
+                                               refnames_tlist),
                         recurse_union_children(op->rarg, parse,
-                                            top_union, refnames_tlist));
+                                               top_union,
+                                               refnames_tlist));
        }
    }
 
@@ -380,6 +391,7 @@ generate_setop_tlist(List *colTypes, int flag,
        Oid         colType = (Oid) lfirsti(i);
        TargetEntry *inputtle = (TargetEntry *) lfirst(input_tlist);
        TargetEntry *reftle = (TargetEntry *) lfirst(refnames_tlist);
+       int32       colTypmod;
 
        Assert(inputtle->resdom->resno == resno);
        Assert(reftle->resdom->resno == resno);
@@ -399,11 +411,6 @@ generate_setop_tlist(List *colTypes, int flag,
         * subquery-scan plans; we don't want phony constants appearing in
         * the output tlists of upper-level nodes!
         */
-       resdom = makeResdom((AttrNumber) resno++,
-                           colType,
-                           -1,
-                           pstrdup(reftle->resdom->resname),
-                           false);
        if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
            expr = inputtle->expr;
        else
@@ -412,10 +419,24 @@ generate_setop_tlist(List *colTypes, int flag,
                                    inputtle->resdom->restype,
                                    inputtle->resdom->restypmod,
                                    0);
-       expr = coerce_to_common_type(NULL,
-                                    expr,
-                                    colType,
-                                    "UNION/INTERSECT/EXCEPT");
+       if (inputtle->resdom->restype == colType)
+       {
+           /* no coercion needed, and believe the input typmod */
+           colTypmod = inputtle->resdom->restypmod;
+       }
+       else
+       {
+           expr = coerce_to_common_type(NULL,
+                                        expr,
+                                        colType,
+                                        "UNION/INTERSECT/EXCEPT");
+           colTypmod = -1;
+       }
+       resdom = makeResdom((AttrNumber) resno++,
+                           colType,
+                           colTypmod,
+                           pstrdup(reftle->resdom->resname),
+                           false);
        tlist = lappend(tlist, makeTargetEntry(resdom, expr));
        input_tlist = lnext(input_tlist);
        refnames_tlist = lnext(refnames_tlist);
@@ -455,6 +476,47 @@ generate_setop_tlist(List *colTypes, int flag,
    return tlist;
 }
 
+/*
+ * Merge typmods of a list of set-operation subplans.
+ *
+ * If the inputs all agree on type and typmod of a particular column,
+ * use that typmod; else use -1.  We assume the result tlist has been
+ * initialized with the types and typmods of the first input subplan.
+ */
+static void
+merge_tlist_typmods(List *tlist, List *planlist)
+{
+   List       *planl;
+
+   foreach(planl, planlist)
+   {
+       Plan   *subplan = (Plan *) lfirst(planl);
+       List   *subtlist = subplan->targetlist;
+       List   *restlist;
+
+       foreach(restlist, tlist)
+       {
+           TargetEntry *restle = (TargetEntry *) lfirst(restlist);
+           TargetEntry *subtle;
+
+           if (restle->resdom->resjunk)
+               continue;
+           Assert(subtlist != NIL);
+           subtle = (TargetEntry *) lfirst(subtlist);
+           while (subtle->resdom->resjunk)
+           {
+               subtlist = lnext(subtlist);
+               Assert(subtlist != NIL);
+               subtle = (TargetEntry *) lfirst(subtlist);
+           }
+           if (restle->resdom->restype != subtle->resdom->restype ||
+               restle->resdom->restypmod != subtle->resdom->restypmod)
+               restle->resdom->restypmod = -1;
+           subtlist = lnext(subtlist);
+       }
+   }
+}
+
 /*
  * Does tlist have same datatypes as requested colTypes?
  *