Sergey Petrunya wrote:
> === modified file 'sql/sql_select.cc'
> --- a/sql/sql_select.cc 2009-07-06 07:57:39 +0000
> +++ b/sql/sql_select.cc 2009-07-06 14:33:29 +0000
> @@ -7916,7 +7916,11 @@
>
> uint i_end= first + join->best_positions[first].n_sj_tables;
> for (uint i= first; i < i_end; i++)
> + {
> + if (i != first)
> + join->best_positions[i].sj_strategy= SJ_OPT_NONE;
> handled_tabs |= join->best_positions[i].table->table->map;
> + }
>
> if (tablenr != first)
> pos->sj_strategy= SJ_OPT_NONE;
Would it not, then, be best to remove the block:
if (tablenr != first)
pos->sj_strategy= SJ_OPT_NONE;
?
Also, I believe it would be best (to help future developers) to put a
short comment in the source code explaining the if() in the for loop.
Something like:
/* best_positions array is already sorted so that first POSITION in
array contains the best semijoin strategy. We remove semijoin
options for all other positions to ensure only a single semijoin
strategy is used for each unique table/join set. */
would suffice.
Cheers!
Jay
