Make the most important optimizer constants user variables

Variables added:
- optimizer_index_block_copy_cost
- optimizer_key_copy_cost
- optimizer_key_next_find_cost
- optimizer_key_compare_cost
- optimizer_row_copy_cost
- optimizer_where_compare_cost

Some rename of defines was done to make the internal defines similar to
the visible ones:
TIME_FOR_COMPARE -> WHERE_COST; WHERE_COST was also "inverted" to be
a number between 0 and 1 that is multiply with accepted records
(similar to other optimizer variables).
TIME_FOR_COMPARE_IDX -> KEY_COMPARE_COST. This is also inverted,
similar to TIME_FOR_COMPARE.
TIME_FOR_COMPARE_ROWID -> ROWID_COMPARE_COST. This is also inverted,
similar to TIME_FOR_COMPARE.

All default costs are identical to what they where before this patch.

Other things:
- Compare factor in get_merge_buffers_cost() was inverted.
- Changed namespace to static in filesort_utils.cc

1 files changed, 9 insertions, 0 deletions

diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc
index a984dea8836..35fb6be53b7 100644
--- a/sql/ha_partition.cc
+++ b/sql/ha_partition.cc
@@ -12145,6 +12145,15 @@ ha_partition::can_convert_nocopy(const Field &field,
   return true;
 }
 
+void ha_partition::set_optimizer_costs(THD *thd)
+{
+  handler::set_optimizer_costs(thd);
+  for (uint i= bitmap_get_first_set(&m_part_info->read_partitions);
+       i < m_tot_parts;
+       i= bitmap_get_next_set(&m_part_info->read_partitions, i))
+    m_file[i]->set_optimizer_costs(thd);
+}
+
 struct st_mysql_storage_engine partition_storage_engine=
 { MYSQL_HANDLERTON_INTERFACE_VERSION };