diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index f0bcff72cb..1fe1ff7349 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -876,6 +876,22 @@ use_physical_tlist(PlannerInfo *root, Path *path, int flags)
 			return false;
 	}
 
+	/*
+	 * For an index-only scan, the "physical tlist" is the index's indextlist.
+	 * We can only return that without a projection if all the index's columns
+	 * are returnable.
+	 */
+	if (path->pathtype == T_IndexOnlyScan)
+	{
+		IndexOptInfo *indexinfo = ((IndexPath *) path)->indexinfo;
+
+		for (i = 0; i < indexinfo->ncolumns; i++)
+		{
+			if (!indexinfo->canreturn[i])
+				return false;
+		}
+	}
+
 	/*
 	 * Also, can't do it if CP_LABEL_TLIST is specified and path is requested
 	 * to emit any sort/group columns that are not simple Vars.  (If they are
diff --git a/src/test/regress/expected/gist.out b/src/test/regress/expected/gist.out
index df1f999829..9db4811045 100644
--- a/src/test/regress/expected/gist.out
+++ b/src/test/regress/expected/gist.out
@@ -281,6 +281,22 @@ select p from gist_tbl where circle(p,1) @> circle(point(0,0),0.95);
  (0,0)
 (1 row)
 
+-- Also check that use_physical_tlist doesn't trigger in such cases.
+explain (verbose, costs off)
+select count(*) from gist_tbl;
+                             QUERY PLAN                              
+---------------------------------------------------------------------
+ Aggregate
+   Output: count(*)
+   ->  Index Only Scan using gist_tbl_multi_index on public.gist_tbl
+(3 rows)
+
+select count(*) from gist_tbl;
+ count 
+-------
+ 10001
+(1 row)
+
 -- This case isn't supported, but it should at least EXPLAIN correctly.
 explain (verbose, costs off)
 select p from gist_tbl order by circle(p,1) <-> point(0,0) limit 1;
diff --git a/src/test/regress/sql/gist.sql b/src/test/regress/sql/gist.sql
index 2a49769ebd..afe2f5c053 100644
--- a/src/test/regress/sql/gist.sql
+++ b/src/test/regress/sql/gist.sql
@@ -143,6 +143,11 @@ explain (verbose, costs off)
 select p from gist_tbl where circle(p,1) @> circle(point(0,0),0.95);
 select p from gist_tbl where circle(p,1) @> circle(point(0,0),0.95);
 
+-- Also check that use_physical_tlist doesn't trigger in such cases.
+explain (verbose, costs off)
+select count(*) from gist_tbl;
+select count(*) from gist_tbl;
+
 -- This case isn't supported, but it should at least EXPLAIN correctly.
 explain (verbose, costs off)
 select p from gist_tbl order by circle(p,1) <-> point(0,0) limit 1;