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, 29 insertions, 4 deletions

diff --git a/storage/example/ha_example.h b/storage/example/ha_example.h
index 2d3fa6d4216..ccd8bbd5446 100644
--- a/storage/example/ha_example.h
+++ b/storage/example/ha_example.h
@@ -150,15 +150,40 @@ public:
   uint max_supported_key_length()    const { return 0; }
 
   /** @brief
-    Called in test_quick_select to determine if indexes should be used.
+    Called in test_quick_select to determine cost of table scan
   */
-  virtual double scan_time() { return (double) (stats.records+stats.deleted) / 20.0+10; }
+  virtual IO_AND_CPU_COST scan_time()
+  {
+    IO_AND_CPU_COST cost;
+    /* 0 blocks,  0.001 ms / row */
+    cost.io= (double) (stats.records+stats.deleted) * avg_io_cost();
+    cost.cpu= 0;
+    return cost;
+  }
 
   /** @brief
     This method will never be called if you do not implement indexes.
   */
-  virtual double read_time(uint, uint, ha_rows rows)
-  { return (double) rows /  20.0+1; }
+  virtual IO_AND_CPU_COST keyread_time(uint, ulong, ha_rows rows,
+                                       ulonglong blocks)
+  {
+    IO_AND_CPU_COST cost;
+    cost.io= blocks * avg_io_cost();
+    cost.cpu= (double) rows * 0.001;
+    return cost;
+  }
+
+  /** @brief
+    Cost of fetching 'rows' records through rnd_pos()
+  */
+  virtual IO_AND_CPU_COST rndpos_time(ha_rows rows)
+  {
+   IO_AND_CPU_COST cost;
+    /* 0 blocks,  0.001 ms / row */
+    cost.io= 0;
+    cost.cpu= (double) rows * avg_io_cost();
+    return cost;
+  }
 
   /*
     Everything below are methods that we implement in ha_example.cc.