commit 1fc14744463594f361c76e04b17716574593da81
Author: Pavan Deolasee <pavan.deolasee@gmail.com>
Date:   Mon Jan 30 08:22:43 2017 +0530

    Invalidate index attributes when index list is invalidated

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 4a053a3..728b388 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -4355,6 +4355,13 @@ RelationGetIndexList(Relation relation)
 		return list_copy(relation->rd_indexlist);
 
 	/*
+	 * If the index list was invalidated, we better also invalidate the index
+	 * attribute list (which should automatically invalidate other attributes
+	 * such as primary key and replica identity)
+	 */
+	relation->rd_indexattr = NULL;
+
+	/*
 	 * We build the list we intend to return (in the caller's context) while
 	 * doing the scan.  After successfully completing the scan, we copy that
 	 * list into the relcache entry.  This avoids cache-context memory leakage