Hi Igor, Just a gentle reminder. Thanks. On 06/10/2015 04:59 PM, Alexander Barkov wrote:
Hi Igor,
I noticed that during Item_cond::fix_fields() and Item_func_between::fix_fields() update these optimizer related SELECT_LEX members:
thd->lex->current_select->cond_count and thd->lex->current_select->between_count
The purpose of these members is to allocate optimizer related buffers in: - update_ref_and_keys() in sql_select.cc and - check_func_dependency() in opt_table_elimination,cc and it seems they have no any other purposes..
From my understanding, this is a dead code and the collected values are never used:
- cond_count and_between_count are later always initialized to 0 before the walk(count_sargable_conds) call in update_ref_and_keys().
- moreover, using the values collected during fix_fields() would not be correct to allocate optimized related buffers, because the code in fix_fields() does not distinguish between different query parts, so the items can be just a part of the SELECT list rather than a part of WHERE/HAVING/ON.
Is the attached patch correct? All tests pass.
Thanks.