Updated optimizer costs in multi_range_read_info_const() and sql_select.cc

- multi_range_read_info_const now uses the new records_in_range interface
- Added handler::avg_io_cost()
- Don't calculate avg_io_cost() in get_sweep_read_cost if avg_io_cost is
  not 1.0.  In this case we trust the avg_io_cost() from the handler.
- Changed test_quick_select to use TIME_FOR_COMPARE instead of
  TIME_FOR_COMPARE_IDX to align this with the rest of the code.
- Fixed bug when using test_if_cheaper_ordering where we didn't use
  keyread if index was changed
- Fixed a bug where we didn't use index only read when using order-by-index
- Added keyread_time() to HEAP.
  The default keyread_time() was optimized for blocks and not suitable for
  HEAP. The effect was the HEAP prefered table scans over ranges for btree
  indexes.
- Fixed get_sweep_read_cost() for HEAP tables
- Ensure that range and ref have same cost for simple ranges
  Added a small cost (MULTI_RANGE_READ_SETUP_COST) to ranges to ensure
  we favior ref for range for simple queries.
- Fixed that matching_candidates_in_table() uses same number of records
  as the rest of the optimizer
- Added avg_io_cost() to JT_EQ_REF cost. This helps calculate the cost for
  HEAP and temporary tables better. A few tests changed because of this.
- heap::read_time() and heap::keyread_time() adjusted to not add +1.
  This was to ensure that handler::keyread_time() doesn't give
  higher cost for heap tables than for normal tables. One effect of
  this is that heap and derived tables stored in heap will prefer
  key access as this is now regarded as cheap.
- Changed cost for index read in sql_select.cc to match
  multi_range_read_info_const(). All index cost calculation is now
  done trough one function.
- 'ref' will now use quick_cost for keys if it exists. This is done
  so that for '=' ranges, 'ref' is prefered over 'range'.
- scan_time() now takes avg_io_costs() into account
- get_delayed_table_estimates() uses block_size and avg_io_cost()
- Removed default argument to test_if_order_by_key(); simplifies code

mysql-test/suite/innodb/r/innodb_mysql.result

@@ -361,13 +361,13 @@ EXPLAIN
 SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
 WHERE t1.name LIKE 'A%';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	PRIMARY,name	name	23	NULL	3	Using where; Using index
+1	SIMPLE	t1	range	PRIMARY,name	name	23	NULL	2	Using where; Using index
 1	SIMPLE	t2	ref	fkey	fkey	5	test.t1.id	1	Using index
 EXPLAIN
 SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
 WHERE t1.name LIKE 'A%' OR FALSE;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	PRIMARY,name	name	23	NULL	3	Using where; Using index
+1	SIMPLE	t1	range	PRIMARY,name	name	23	NULL	2	Using where; Using index
 1	SIMPLE	t2	ref	fkey	fkey	5	test.t1.id	1	Using index
 DROP TABLE t1,t2;
 CREATE TABLE t1 (
@@ -405,7 +405,7 @@ DELETE FROM t1;
 # Masking (#) number in "rows" column of the following EXPLAIN output, as it may vary (bug#47746).
 EXPLAIN SELECT DISTINCT t1.name, t1.dept FROM t1 WHERE t1.name='rs5';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	name	name	44	NULL	#	Using where; Using index for group-by
+1	SIMPLE	t1	ref	name	name	22	const	#	Using where; Using index
 SELECT DISTINCT t1.name, t1.dept FROM t1 WHERE t1.name='rs5';
 name	dept
 DROP TABLE t1;
@@ -1312,13 +1312,13 @@ EXPLAIN SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
 id	1
 select_type	SIMPLE
 table	t1
-type	index
+type	range
 possible_keys	bkey
-key	PRIMARY
-key_len	4
+key	bkey
+key_len	5
 ref	NULL
 rows	32
-Extra	Using where
+Extra	Using where; Using index; Using filesort
 SELECT * FROM t1 WHERE b BETWEEN 1 AND 2 ORDER BY a;
 a	b
 1	2
@@ -2367,12 +2367,12 @@ EXPLAIN SELECT c FROM foo2 WHERE b>2;;
 id	1
 select_type	SIMPLE
 table	foo2
-type	index
+type	range
 possible_keys	b
 key	b
 key_len	5
 ref	NULL
-rows	6
+rows	5
 Extra	Using where; Using index
 EXPLAIN SELECT c FROM bar WHERE c>2;;
 id	1
@@ -3067,7 +3067,7 @@ f1	f2	f3	f4
 EXPLAIN SELECT * FROM t1 WHERE f2 = 1 AND f4 = TRUE
 ORDER BY f1 DESC LIMIT 5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	f2,f4	PRIMARY	4	NULL	5	Using where
+1	SIMPLE	t1	range	f2,f4	f4	1	NULL	22	Using where
 DROP TABLE t1;
 #
 # Bug#54117 crash in thr_multi_unlock, temporary table