Hi! > 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..
Correct. > 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(). And the call to check_func_dependency() is done after this call. > - 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. This would note be a problem as the count was supposed to be an upper bound. As it's not normal that you have many IF or BETWEEN in the SELECT part, this was not a problem. I looked at the patch and it's ok to commit. Regards, Monty _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
