diff options
Diffstat (limited to 'sql/filesort_utils.cc')
| -rw-r--r-- | sql/filesort_utils.cc | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/sql/filesort_utils.cc b/sql/filesort_utils.cc index 341e43ea6cf..6790016c838 100644 --- a/sql/filesort_utils.cc +++ b/sql/filesort_utils.cc @@ -23,17 +23,16 @@ PSI_memory_key key_memory_Filesort_buffer_sort_keys; -namespace { /** A local helper function. See comments for get_merge_buffers_cost(). - */ -double get_merge_cost(ha_rows num_elements, ha_rows num_buffers, uint elem_size) +*/ + +static double get_merge_cost(double rowid_compare_cost, ha_rows num_elements, + ha_rows num_buffers, uint elem_size) { - return - 2.0 * ((double) num_elements * elem_size) / IO_SIZE - + (double) num_elements * log((double) num_buffers) / - (TIME_FOR_COMPARE_ROWID * M_LN2); -} + return (2.0 * ((double) num_elements * elem_size) / IO_SIZE + + (double) num_elements * log((double) num_buffers) * + rowid_compare_cost / M_LN2); } /** @@ -43,20 +42,21 @@ double get_merge_cost(ha_rows num_elements, ha_rows num_buffers, uint elem_size) see comments for get_merge_buffers_cost(). TODO: Use this function for Unique::get_use_cost(). */ -double get_merge_many_buffs_cost_fast(ha_rows num_rows, + +double get_merge_many_buffs_cost_fast(THD *thd, + ha_rows num_rows, ha_rows num_keys_per_buffer, uint elem_size) { ha_rows num_buffers= num_rows / num_keys_per_buffer; ha_rows last_n_elems= num_rows % num_keys_per_buffer; - double total_cost; + double total_cost, rowid_compare_cost= ROWID_COMPARE_COST_THD(thd); // Calculate CPU cost of sorting buffers. total_cost= ((num_buffers * num_keys_per_buffer * log(1.0 + num_keys_per_buffer) + - last_n_elems * log(1.0 + last_n_elems)) / - TIME_FOR_COMPARE_ROWID); - + last_n_elems * log(1.0 + last_n_elems)) * rowid_compare_cost); + // Simulate behavior of merge_many_buff(). while (num_buffers >= MERGEBUFF2) { @@ -69,14 +69,16 @@ double get_merge_many_buffs_cost_fast(ha_rows num_rows, // Cost of merge sort 'num_merge_calls'. total_cost+= num_merge_calls * - get_merge_cost(num_keys_per_buffer * MERGEBUFF, MERGEBUFF, elem_size); + get_merge_cost(rowid_compare_cost, num_keys_per_buffer * MERGEBUFF, + MERGEBUFF, elem_size); // # of records in remaining buffers. last_n_elems+= num_remaining_buffs * num_keys_per_buffer; // Cost of merge sort of remaining buffers. total_cost+= - get_merge_cost(last_n_elems, 1 + num_remaining_buffs, elem_size); + get_merge_cost(rowid_compare_cost, last_n_elems, 1 + num_remaining_buffs, + elem_size); num_buffers= num_merge_calls; num_keys_per_buffer*= MERGEBUFF; @@ -84,7 +86,8 @@ double get_merge_many_buffs_cost_fast(ha_rows num_rows, // Simulate final merge_buff call. last_n_elems+= num_keys_per_buffer * num_buffers; - total_cost+= get_merge_cost(last_n_elems, 1 + num_buffers, elem_size); + total_cost+= get_merge_cost(rowid_compare_cost, last_n_elems, 1 + num_buffers, + elem_size); return total_cost; } |