bug#28570: handler::index_read() is called with different find_flag when

ORDER BY is used

The range analysis module did not correctly signal to the 
handler that a range represents a ref (EQ_RANGE flag). This causes 
non-range queries like 
SELECT ... FROM ... WHERE keypart_1=const, ..., keypart_n=const 
ORDER BY ... FOR UPDATE
to wait for a lock unneccesarily if another running transaction uses
SELECT ... FOR UPDATE on the same table.

Fixed by setting EQ_RANGE for all range accesses that represent 
an equality predicate. 


mysql-test/r/innodb_mysql.result:
  bug#28570: Test Result
mysql-test/t/innodb_mysql.test:
  bug#28570: Test Case
sql/handler.cc:
  bug#28570: Updated comment
sql/opt_range.cc:
  bug#28570: Removed the criterion that key has to be unique (HA_NOSAME) in 
  order for the EQ_RANGE flag to be set. It is sufficient that the range 
  represent a ref access.

mysql-test/r/innodb_mysql.result

@@ -1007,4 +1007,22 @@ CALL p1();
 CALL p1();
 DROP PROCEDURE p1;
 DROP TABLE t1;
+CREATE TABLE t1 (
+a INT,
+b INT,
+KEY (b)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (1,10), (2,10), (2,20), (3,30);
+START TRANSACTION;
+SELECT * FROM t1 WHERE b=20 FOR UPDATE;
+a	b
+2	20
+START TRANSACTION;
+SELECT * FROM t1 WHERE b=10 ORDER BY A FOR UPDATE;
+a	b
+1	10
+2	10
+ROLLBACK;
+ROLLBACK;
+DROP TABLE t1;
 End of 5.0 tests

mysql-test/t/innodb_mysql.test

@@ -840,5 +840,34 @@ DISCONNECT con2;
 DROP PROCEDURE p1;
 DROP TABLE t1;
 
+#
+# Bug #28570: handler::index_read() is called with different find_flag when 
+# ORDER BY is used
+#
+
+CREATE TABLE t1 (
+  a INT,
+  b INT,
+  KEY (b)
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES (1,10), (2,10), (2,20), (3,30);
+
+START TRANSACTION;
+SELECT * FROM t1 WHERE b=20 FOR UPDATE;
+
+--connect (conn2, localhost, root,,test)
+
+# This statement gives a "failed: 1205: Lock wait timeout exceeded; try 
+# restarting transaction" message when the bug is present.
+START TRANSACTION;
+SELECT * FROM t1 WHERE b=10 ORDER BY A FOR UPDATE;
+ROLLBACK;
+
+--disconnect conn2
+--connection default
+
+ROLLBACK;
+DROP TABLE t1;
 
 --echo End of 5.0 tests

sql/handler.cc

@@ -2610,7 +2610,8 @@ int handler::read_multi_range_next(KEY_MULTI_RANGE **found_range_p)
     read_range_first()
     start_key		Start key. Is 0 if no min range
     end_key		End key.  Is 0 if no max range
-    eq_range_arg	Set to 1 if start_key == end_key
+    eq_range_arg	Set to 1 if start_key == end_key and the range endpoints
+                        will not change during query execution.
     sorted		Set to 1 if result should be sorted per key
 
   NOTES

sql/opt_range.cc

@@ -6369,8 +6369,7 @@ QUICK_RANGE_SELECT *get_quick_select_for_ref(THD *thd, TABLE *table,
   range->min_key=range->max_key=(char*) ref->key_buff;
   range->min_length=range->max_length=ref->key_length;
   range->flag= ((ref->key_length == key_info->key_length &&
-		 (key_info->flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
-		 HA_NOSAME) ? EQ_RANGE : 0);
+		 (key_info->flags & HA_END_SPACE_KEY) == 0) ? EQ_RANGE : 0);
 
   if (!(quick->key_parts=key_part=(KEY_PART *)
 	alloc_root(&quick->alloc,sizeof(KEY_PART)*ref->key_parts)))