--- src/backend/optimizer/prep/prepunion.c.orig	2017-09-24 17:40:34.888790877 +0200
+++ src/backend/optimizer/prep/prepunion.c	2017-09-24 17:41:39.796748743 +0200
@@ -2413,7 +2413,7 @@
  * 		Find AppendRelInfo structures for all relations specified by relids.
  *
  * The AppendRelInfos are returned in an array, which can be pfree'd by the
- * caller. *nappinfos is set to the the number of entries in the array.
+ * caller. *nappinfos is set to the number of entries in the array.
  */
 AppendRelInfo **
 find_appinfos_by_relids(PlannerInfo *root, Relids relids, int *nappinfos)