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/main/stat_tables.result

@@ -74,7 +74,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	supplier	ref	PRIMARY,i_s_nationkey	i_s_nationkey	5	dbt3_s001.nation.n_nationkey	1	
 1	SIMPLE	customer	ref	PRIMARY,i_c_nationkey	i_c_nationkey	5	dbt3_s001.nation.n_nationkey	6	
 1	SIMPLE	orders	ref|filter	PRIMARY,i_o_orderdate,i_o_custkey	i_o_custkey|i_o_orderdate	5|4	dbt3_s001.customer.c_custkey	15 (12%)	Using where; Using rowid filter
-1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	4	dbt3_s001.orders.o_orderkey	4	Using where
+1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	i_l_orderkey	4	dbt3_s001.orders.o_orderkey	4	Using where
 select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue
 from customer, orders, lineitem, supplier, nation, region
 where c_custkey = o_custkey and l_orderkey = o_orderkey
@@ -181,7 +181,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	supplier	ref	PRIMARY,i_s_nationkey	i_s_nationkey	5	dbt3_s001.nation.n_nationkey	1	
 1	SIMPLE	customer	ref	PRIMARY,i_c_nationkey	i_c_nationkey	5	dbt3_s001.nation.n_nationkey	6	
 1	SIMPLE	orders	ref|filter	PRIMARY,i_o_orderdate,i_o_custkey	i_o_custkey|i_o_orderdate	5|4	dbt3_s001.customer.c_custkey	15 (12%)	Using where; Using rowid filter
-1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	4	dbt3_s001.orders.o_orderkey	4	Using where
+1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	i_l_orderkey	4	dbt3_s001.orders.o_orderkey	4	Using where
 select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue
 from customer, orders, lineitem, supplier, nation, region
 where c_custkey = o_custkey and l_orderkey = o_orderkey
@@ -214,10 +214,10 @@ order by o_year;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	region	ALL	PRIMARY	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
 1	SIMPLE	part	ALL	PRIMARY	NULL	NULL	NULL	200	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	i_l_suppkey_partkey	5	dbt3_s001.part.p_partkey	30	Using index condition
+1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity	i_l_partkey	5	dbt3_s001.part.p_partkey	30	Using where
 1	SIMPLE	supplier	eq_ref	PRIMARY,i_s_nationkey	PRIMARY	4	dbt3_s001.lineitem.l_suppkey	1	Using where
+1	SIMPLE	orders	eq_ref|filter	PRIMARY,i_o_orderdate,i_o_custkey	PRIMARY|i_o_orderdate	4|4	dbt3_s001.lineitem.l_orderkey	1 (27%)	Using where; Using rowid filter
 1	SIMPLE	n2	eq_ref	PRIMARY	PRIMARY	4	dbt3_s001.supplier.s_nationkey	1	
-1	SIMPLE	orders	eq_ref	PRIMARY,i_o_orderdate,i_o_custkey	PRIMARY	4	dbt3_s001.lineitem.l_orderkey	1	Using where
 1	SIMPLE	customer	eq_ref	PRIMARY,i_c_nationkey	PRIMARY	4	dbt3_s001.orders.o_custkey	1	Using where
 1	SIMPLE	n1	eq_ref	PRIMARY,i_n_regionkey	PRIMARY	4	dbt3_s001.customer.c_nationkey	1	Using where
 select o_year,
@@ -337,7 +337,7 @@ and o_orderkey=l_orderkey and p_partkey=l_partkey;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	part	range	PRIMARY,i_p_retailprice	i_p_retailprice	9	NULL	1	Using index condition
 1	SIMPLE	orders	ref	PRIMARY,i_o_orderdate	i_o_orderdate	4	const	1	
-1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	4	dbt3_s001.orders.o_orderkey	4	Using where
+1	SIMPLE	lineitem	ref	PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_orderkey,i_l_orderkey_quantity	i_l_orderkey	4	dbt3_s001.orders.o_orderkey	4	Using where
 select o_orderkey, p_partkey
 from part, lineitem, orders
 where p_retailprice > 1100 and o_orderdate='1997-01-01'