TEMPORARY PUSH: Changing all cost calculation to be given in ms10.7-selectivity-old

- Added tests/check_costs.pl, a tool to verify optimizer cost calculations.
  - Most costs has been found with this program. All steps to calculate
    the new costs are documented in Docs/optimizer.costs
- User optimizer_cost variables are given in usec (as individual
  costs can be very small). Internally they are stored in ms.
- Changed DISK_READ_COST (was DISK_SEEK_BASE_COST) from a hard disk cost
  (9 ms) to common SSD cost (400MB/sec).
- Changed the following handler functions to return IO_AND_CPU_COST.
  This makes it easy to apply different cost modifiers in ha_..time()
  functions for io and cpu costs.
  - scan_time()
  - rndpos_time()
  - keyread_time()
- Enhanched keyread_time() to calculate the full cost of reading of a set
  of keys with a given number of ranges and optionall number of blocks that
  need to be accessed.
- Removed read_time() as keyread_time() + rndpos_time() is the same thing.
- Added the following new optimizer_variables:
  - optimizer_scan_lookup_cost
  - optimizer_row_lookup_cost
  - optimizer_index_lookup_cost
  - optimizer_disk_read_cost
- Added include/my_tracker.h  ; Useful include file to quickly test costs
  of a function.
- Tuned sequence and heap engine costs (rest will be done in an updated
  commit)

1 files changed, 3 insertions, 1 deletions

diff --git a/sql/sql_explain.h b/sql/sql_explain.h
index bfd52290374..823a94a64f0 100644
--- a/sql/sql_explain.h
+++ b/sql/sql_explain.h
@@ -722,7 +722,7 @@ public:
 class Explain_table_access : public Sql_alloc
 {
 public:
-  Explain_table_access(MEM_ROOT *root) :
+  Explain_table_access(MEM_ROOT *root, bool timed) :
     derived_select_number(0),
     non_merged_sjm_number(0),
     extra_tags(root),
@@ -735,6 +735,7 @@ public:
     pushed_index_cond(NULL),
     sjm_nest(NULL),
     pre_join_sort(NULL),
+    jbuf_unpack_tracker(timed),
     rowid_filter(NULL)
   {}
   ~Explain_table_access() { delete sjm_nest; }
@@ -843,6 +844,7 @@ public:
   Gap_time_tracker extra_time_tracker;
 
   Table_access_tracker jbuf_tracker;
+  Time_and_counter_tracker jbuf_unpack_tracker;
   
   Explain_rowid_filter *rowid_filter;