More tests

mysql-test/main/order_by_limit_join.result

@@ -163,5 +163,88 @@ JS
         "use_shortcut_plan": true
     }
 ]
+#
+# Counter example with large limit
+#
+# Table t1 is not the first, have to use temporary+filesort:
+set optimizer_join_limit_pref_ratio=0;
+explain
+select
+*
+from 
+t1
+join t10 on t1.a=t10.a
+join t11 on t1.b=t11.b
+order by
+t1.col1
+limit 5000;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t10	ALL	a	NULL	NULL	NULL	100	Using where; Using temporary; Using filesort
+1	SIMPLE	t1	ref	a,b	a	5	test.t10.a	100	Using where
+1	SIMPLE	t11	ref	b	b	5	test.t1.b	1	
+# Same plan as above:
+# Table t1 is not the first, have to use temporary+filesort:
+set optimizer_join_limit_pref_ratio=10;
+explain
+select
+*
+from 
+t1
+join t10 on t1.a=t10.a
+join t11 on t1.b=t11.b
+order by
+t1.col1
+limit 5000;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t10	ALL	a	NULL	NULL	NULL	100	Using where; Using temporary; Using filesort
+1	SIMPLE	t1	ref	a,b	a	5	test.t10.a	100	Using where
+1	SIMPLE	t11	ref	b	b	5	test.t1.b	1	
+set @trace=(select trace from information_schema.optimizer_trace);
+select json_detailed(json_extract(@trace, '$**.limit_shortcut_choice')) as JS;
+JS
+[
+    {
+        "limit_fraction": 0.5,
+        "test_if_skip_sort_order": 
+        [
+            {
+                "reconsidering_access_paths_for_index_ordering": 
+                {
+                    "clause": "ORDER BY",
+                    "fanout": 1,
+                    "read_time": 53.27053125,
+                    "table": "t1",
+                    "rows_estimation": 10000,
+                    "possible_keys": 
+                    [
+                        {
+                            "index": "a",
+                            "can_resolve_order": false,
+                            "cause": "not usable index for the query"
+                        },
+                        {
+                            "index": "b",
+                            "can_resolve_order": false,
+                            "cause": "not usable index for the query"
+                        },
+                        {
+                            "index": "col1",
+                            "can_resolve_order": true,
+                            "updated_limit": 5000,
+                            "index_scan_time": 5000,
+                            "usable": false,
+                            "cause": "cost"
+                        }
+                    ]
+                }
+            }
+        ],
+        "can_skip_filesort": false,
+        "full_join_cost": 46064.98442,
+        "shortcut_join_cost": 24059.12698,
+        "use_shortcut_plan": false
+    }
+]
 set optimizer_trace=@tmp_os;
+set optimizer_join_limit_pref_ratio=default;
 drop table t1, t10, t11;

mysql-test/main/order_by_limit_join.test

@@ -94,7 +94,33 @@ eval $query;
 set @trace=(select trace from information_schema.optimizer_trace);
 select json_detailed(json_extract(@trace, '$**.limit_shortcut_choice')) as JS;
 
-set optimizer_trace=@tmp_os;
+--echo #
+--echo # Counter example with large limit
+--echo #
+let $query= explain
+select
+  *
+from 
+  t1
+  join t10 on t1.a=t10.a
+  join t11 on t1.b=t11.b
+order by
+  t1.col1
+limit 5000;
 
+--echo # Table t1 is not the first, have to use temporary+filesort:
+set optimizer_join_limit_pref_ratio=0;
+eval $query;
+
+--echo # Same plan as above:
+--echo # Table t1 is not the first, have to use temporary+filesort:
+set optimizer_join_limit_pref_ratio=10;
+eval $query;
+
+set @trace=(select trace from information_schema.optimizer_trace);
+select json_detailed(json_extract(@trace, '$**.limit_shortcut_choice')) as JS;
+
+set optimizer_trace=@tmp_os;
+set optimizer_join_limit_pref_ratio=default;
 drop table t1, t10, t11;