diff options
Diffstat (limited to 'sql/opt_subselect.cc')
| -rw-r--r-- | sql/opt_subselect.cc | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc index 9bf1aaf4039..bab061a2ac7 100644 --- a/sql/opt_subselect.cc +++ b/sql/opt_subselect.cc @@ -3176,6 +3176,25 @@ at_sjmat_pos(const JOIN *join, table_map remaining_tables, const JOIN_TAB *tab, } +/* + Re-calculate values of join->best_positions[start..end].prefix_record_count +*/ + +static void recalculate_prefix_record_count(JOIN *join, uint start, uint end) +{ + for (uint j= start; j < end ;j++) + { + double prefix_count; + if (j == join->const_tables) + prefix_count= 1.0; + else + prefix_count= join->best_positions[j-1].prefix_record_count * + join->best_positions[j-1].records_read; + + join->best_positions[j].prefix_record_count= prefix_count; + } +} + /* Fix semi-join strategies for the picked join order @@ -3245,6 +3264,8 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join) sjm->is_sj_scan= FALSE; memcpy(pos - sjm->tables + 1, sjm->positions, sizeof(POSITION) * sjm->tables); + recalculate_prefix_record_count(join, tablenr - sjm->tables + 1, + tablenr); first= tablenr - sjm->tables + 1; join->best_positions[first].n_sj_tables= sjm->tables; join->best_positions[first].sj_strategy= SJ_OPT_MATERIALIZE; @@ -3258,6 +3279,7 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join) first= pos->sjmat_picker.sjm_scan_last_inner - sjm->tables + 1; memcpy(join->best_positions + first, sjm->positions, sizeof(POSITION) * sjm->tables); + recalculate_prefix_record_count(join, first, first + sjm->tables); join->best_positions[first].sj_strategy= SJ_OPT_MATERIALIZE_SCAN; join->best_positions[first].n_sj_tables= sjm->tables; /* |