3 files changed, 26 insertions, 54 deletions

diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index d2346cbe02e..23c74f7d90a 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -1196,15 +1196,15 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid,
  * returns true, otherwise returns false.
  *
  * Optionally returns pointers to the extracted Var/Const nodes, when passed
- * non-null pointers (varp, cstp and isgtp). The isgt flag specifies whether
- * the Var node is on the left (false) or right (true) side of the operator.
+ * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies
+ * on which side of the operator we found the Var node.
  */
 bool
-examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *isgtp)
+examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
 {
 	Var	   *var;
 	Const  *cst;
-	bool	isgt;
+	bool	varonleft;
 	Node   *leftop,
 		   *rightop;
 
@@ -1225,13 +1225,13 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *isgtp)
 	{
 		var = (Var *) leftop;
 		cst = (Const *) rightop;
-		isgt = false;
+		varonleft = true;
 	}
 	else if (IsA(leftop, Const) && IsA(rightop, Var))
 	{
 		var = (Var *) rightop;
 		cst = (Const *) leftop;
-		isgt = true;
+		varonleft = false;
 	}
 	else
 		return false;
@@ -1243,8 +1243,8 @@ examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *isgtp)
 	if (cstp)
 		*cstp = cst;
 
-	if (isgtp)
-		*isgtp = isgt;
+	if (varonleftp)
+		*varonleftp = varonleft;
 
 	return true;
 }
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index e5a4e86c5d8..2b685ec67a2 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1581,18 +1581,15 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			OpExpr	   *expr = (OpExpr *) clause;
 			FmgrInfo	opproc;
 
-			/* get procedure computing operator selectivity */
-			RegProcedure oprrest = get_oprrest(expr->opno);
-
 			/* valid only after examine_opclause_expression returns true */
 			Var		   *var;
 			Const	   *cst;
-			bool		isgt;
+			bool		varonleft;
 
 			fmgr_info(get_opcode(expr->opno), &opproc);
 
 			/* extract the var and const from the expression */
-			if (examine_opclause_expression(expr, &var, &cst, &isgt))
+			if (examine_opclause_expression(expr, &var, &cst, &varonleft))
 			{
 				int			idx;
 
@@ -1629,46 +1626,21 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					if (RESULT_IS_FINAL(matches[i], is_or))
 						continue;
 
-					switch (oprrest)
-					{
-						case F_EQSEL:
-						case F_NEQSEL:
-
-							/*
-							 * We don't care about isgt in equality, because
-							 * it does not matter whether it's (var op const)
-							 * or (const op var).
-							 */
-							match = DatumGetBool(FunctionCall2Coll(&opproc,
-																   DEFAULT_COLLATION_OID,
-																   cst->constvalue,
-																   item->values[idx]));
-
-							break;
-
-						case F_SCALARLTSEL: /* column < constant */
-						case F_SCALARLESEL: /* column <= constant */
-						case F_SCALARGTSEL: /* column > constant */
-						case F_SCALARGESEL: /* column >= constant */
-
-							/*
-							 * First check whether the constant is below the
-							 * lower boundary (in that case we can skip the
-							 * bucket, because there's no overlap).
-							 */
-							if (isgt)
-								match = DatumGetBool(FunctionCall2Coll(&opproc,
-																	   DEFAULT_COLLATION_OID,
-																	   cst->constvalue,
-																	   item->values[idx]));
-							else
-								match = DatumGetBool(FunctionCall2Coll(&opproc,
-																	   DEFAULT_COLLATION_OID,
-																	   item->values[idx],
-																	   cst->constvalue));
-
-							break;
-					}
+					/*
+					 * First check whether the constant is below the lower
+					 * boundary (in that case we can skip the bucket, because
+					 * there's no overlap).
+					 */
+					if (varonleft)
+						match = DatumGetBool(FunctionCall2Coll(&opproc,
+															   DEFAULT_COLLATION_OID,
+															   item->values[idx],
+															   cst->constvalue));
+					else
+						match = DatumGetBool(FunctionCall2Coll(&opproc,
+															   DEFAULT_COLLATION_OID,
+															   cst->constvalue,
+															   item->values[idx]));
 
 					/* update the match bitmap with the result */
 					matches[i] = RESULT_MERGE(matches[i], is_or, match);
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index c7f01d4edc7..8433c34f6d7 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -98,7 +98,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
 									int numattrs, AttrNumber *attnums);
 
 extern bool examine_opclause_expression(OpExpr *expr, Var **varp,
-										Const **cstp, bool *isgtp);
+										Const **cstp, bool *varonleftp);
 
 extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root,
 											  StatisticExtInfo *stat,