Fix oversight in construction of sort/unique plans for UniquePaths.

If the original IN operator is cross-type, for example int8 = int4,
we need to use int4 < int4 to sort the inner data and int4 = int4
to unique-ify it.  We got the first part of that right, but tried to
use the original IN operator for the equality checks.  Per bug #5472
from Vlad Romascanu.

Backpatch to 8.4, where the bug was introduced by the patch that unified
SortClause and GroupClause.  I was able to take out a whole lot of on-the-fly
calls of get_equality_op_for_ordering_op(), but failed to realize that
I needed to put one back in right here :-(

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index a87c2b80fb2aa6c52384beab172969eb62a4018f..3d6f9f94faa2f050fbb4ab411ad10da5e695d449 100644 (file)
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
  *
  *
  * IDENTIFICATION

- *       $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.274 2010/03/28 22:59:32 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.275 2010/05/25 17:44:41 tgl Exp $

  *
  *-------------------------------------------------------------------------
  */
  *
  *-------------------------------------------------------------------------
  */


@@ -784,6 +784,7 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path)
                {
                        Oid                     in_oper = lfirst_oid(l);
                        Oid                     sortop;
                {
                        Oid                     in_oper = lfirst_oid(l);
                        Oid                     sortop;

+                       Oid                     eqop;

                        TargetEntry *tle;
                        SortGroupClause *sortcl;
 
                        TargetEntry *tle;
                        SortGroupClause *sortcl;
 


@@ -791,13 +792,26 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path)
                        if (!OidIsValid(sortop))        /* shouldn't happen */
                                elog(ERROR, "could not find ordering operator for equality operator %u",
                                         in_oper);
                        if (!OidIsValid(sortop))        /* shouldn't happen */
                                elog(ERROR, "could not find ordering operator for equality operator %u",
                                         in_oper);

+
+                       /*
+                        * The Unique node will need equality operators.  Normally these
+                        * are the same as the IN clause operators, but if those are
+                        * cross-type operators then the equality operators are the ones
+                        * for the IN clause operators' RHS datatype.
+                        */
+                       eqop = get_equality_op_for_ordering_op(sortop, NULL);
+                       if (!OidIsValid(eqop))          /* shouldn't happen */
+                               elog(ERROR, "could not find equality operator for ordering operator %u",
+                                        sortop);
+

                        tle = get_tle_by_resno(subplan->targetlist,
                                                                   groupColIdx[groupColPos]);
                        Assert(tle != NULL);
                        tle = get_tle_by_resno(subplan->targetlist,
                                                                   groupColIdx[groupColPos]);
                        Assert(tle != NULL);

+

                        sortcl = makeNode(SortGroupClause);
                        sortcl->tleSortGroupRef = assignSortGroupRef(tle,
                                                                                                                 subplan->targetlist);
                        sortcl = makeNode(SortGroupClause);
                        sortcl->tleSortGroupRef = assignSortGroupRef(tle,
                                                                                                                 subplan->targetlist);

-                       sortcl->eqop = in_oper;
+                       sortcl->eqop = eqop;

                        sortcl->sortop = sortop;
                        sortcl->nulls_first = false;
                        sortList = lappend(sortList, sortcl);
                        sortcl->sortop = sortop;
                        sortcl->nulls_first = false;
                        sortList = lappend(sortList, sortcl);