diff --git a/mysql-test/r/group_min_max.result b/mysql-test/r/group_min_max.result index f2f488650d5..58be2af1bb8 100644 --- a/mysql-test/r/group_min_max.result +++ b/mysql-test/r/group_min_max.result @@ -2429,3 +2429,18 @@ id select_type table type possible_keys key key_len ref rows Extra Warnings: Note 1003 select sql_buffer_result `test`.`t1`.`a` AS `a`,(max(`test`.`t1`.`b`) + 1) AS `max(b)+1` from `test`.`t1` where (`test`.`t1`.`a` = 0) group by `test`.`t1`.`a` drop table t1; +CREATE TABLE t1 (a int, b int, c int, d int, +KEY foo (c,d,a,b), KEY bar (c,a,b,d)); +INSERT INTO t1 VALUES (1, 1, 1, 1), (1, 1, 1, 2), (1, 1, 1, 3), (1, 1, 1, 4); +INSERT INTO t1 SELECT * FROM t1; +INSERT INTO t1 SELECT * FROM t1; +INSERT INTO t1 SELECT a,b,c+1,d FROM t1; +EXPLAIN SELECT DISTINCT c FROM t1 WHERE d=4; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 range NULL foo 10 NULL 9 Using where; Using index for group-by +SELECT DISTINCT c FROM t1 WHERE d=4; +c +1 +2 +DROP TABLE t1; +End of 5.0 tests diff --git a/mysql-test/t/group_min_max.test b/mysql-test/t/group_min_max.test index f7aed7301fb..e124bf9e786 100644 --- a/mysql-test/t/group_min_max.test +++ b/mysql-test/t/group_min_max.test @@ -935,3 +935,26 @@ insert into t1 (a,b) select a, max(b)+1 from t1 where a = 0 group by a; select * from t1; explain extended select sql_buffer_result a, max(b)+1 from t1 where a = 0 group by a; drop table t1; + + +# +# Bug #41610: key_infix_len can be overwritten causing some group by queries +# to return no rows +# + +CREATE TABLE t1 (a int, b int, c int, d int, + KEY foo (c,d,a,b), KEY bar (c,a,b,d)); + +INSERT INTO t1 VALUES (1, 1, 1, 1), (1, 1, 1, 2), (1, 1, 1, 3), (1, 1, 1, 4); +INSERT INTO t1 SELECT * FROM t1; +INSERT INTO t1 SELECT * FROM t1; +INSERT INTO t1 SELECT a,b,c+1,d FROM t1; + +#Should be non-empty +--ordered_result +EXPLAIN SELECT DISTINCT c FROM t1 WHERE d=4; +SELECT DISTINCT c FROM t1 WHERE d=4; + +DROP TABLE t1; + +--echo End of 5.0 tests diff --git a/sql/opt_range.cc b/sql/opt_range.cc index ebebfafb5d8..018fc8a9d44 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -7775,32 +7775,37 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) */ KEY *cur_index_info= table->key_info; KEY *cur_index_info_end= cur_index_info + table->s->keys; - KEY_PART_INFO *cur_part= NULL; - KEY_PART_INFO *end_part; /* Last part for loops. */ - /* Last index part. */ - KEY_PART_INFO *last_part= NULL; - KEY_PART_INFO *first_non_group_part= NULL; - KEY_PART_INFO *first_non_infix_part= NULL; - uint key_infix_parts= 0; - uint cur_group_key_parts= 0; - uint cur_group_prefix_len= 0; /* Cost-related variables for the best index so far. */ double best_read_cost= DBL_MAX; ha_rows best_records= 0; SEL_ARG *best_index_tree= NULL; ha_rows best_quick_prefix_records= 0; uint best_param_idx= 0; - double cur_read_cost= DBL_MAX; - ha_rows cur_records; + + const uint pk= param->table->s->primary_key; SEL_ARG *cur_index_tree= NULL; ha_rows cur_quick_prefix_records= 0; uint cur_param_idx=MAX_KEY; - key_map cur_used_key_parts; - uint pk= param->table->s->primary_key; for (uint cur_index= 0 ; cur_index_info != cur_index_info_end ; cur_index_info++, cur_index++) { + KEY_PART_INFO *cur_part; + KEY_PART_INFO *end_part; /* Last part for loops. */ + /* Last index part. */ + KEY_PART_INFO *last_part; + KEY_PART_INFO *first_non_group_part; + KEY_PART_INFO *first_non_infix_part; + uint key_infix_parts; + uint cur_group_key_parts= 0; + uint cur_group_prefix_len= 0; + double cur_read_cost; + ha_rows cur_records; + key_map used_key_parts_map; + uint cur_key_infix_len= 0; + byte cur_key_infix[MAX_KEY_LENGTH]; + uint cur_used_key_parts; + /* Check (B1) - if current index is covering. */ if (!table->used_keys.is_set(cur_index)) goto next_index; @@ -7879,7 +7884,7 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) else if (join->select_distinct) { select_items_it.rewind(); - cur_used_key_parts.clear_all(); + used_key_parts_map.clear_all(); uint max_key_part= 0; while ((item= select_items_it++)) { @@ -7890,13 +7895,13 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) Check if this attribute was already present in the select list. If it was present, then its corresponding key part was alredy used. */ - if (cur_used_key_parts.is_set(key_part_nr)) + if (used_key_parts_map.is_set(key_part_nr)) continue; if (key_part_nr < 1 || key_part_nr > join->fields_list.elements) goto next_index; cur_part= cur_index_info->key_part + key_part_nr - 1; cur_group_prefix_len+= cur_part->store_length; - cur_used_key_parts.set_bit(key_part_nr); + used_key_parts_map.set_bit(key_part_nr); ++cur_group_key_parts; max_key_part= max(max_key_part,key_part_nr); } @@ -7908,7 +7913,7 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) */ ulonglong all_parts, cur_parts; all_parts= (1<> 1; + cur_parts= used_key_parts_map.to_ulonglong() >> 1; if (all_parts != cur_parts) goto next_index; } @@ -7958,7 +7963,8 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) &dummy); if (!get_constant_key_infix(cur_index_info, index_range_tree, first_non_group_part, min_max_arg_part, - last_part, thd, key_infix, &key_infix_len, + last_part, thd, cur_key_infix, + &cur_key_infix_len, &first_non_infix_part)) goto next_index; } @@ -8010,9 +8016,9 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) } /* If we got to this point, cur_index_info passes the test. */ - key_infix_parts= key_infix_len ? + key_infix_parts= cur_key_infix_len ? (first_non_infix_part - first_non_group_part) : 0; - used_key_parts= cur_group_key_parts + key_infix_parts; + cur_used_key_parts= cur_group_key_parts + key_infix_parts; /* Compute the cost of using this index. */ if (tree) @@ -8024,7 +8030,7 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) cur_quick_prefix_records= check_quick_select(param, cur_param_idx, cur_index_tree); } - cost_group_min_max(table, cur_index_info, used_key_parts, + cost_group_min_max(table, cur_index_info, cur_used_key_parts, cur_group_key_parts, tree, cur_index_tree, cur_quick_prefix_records, have_min, have_max, &cur_read_cost, &cur_records); @@ -8035,7 +8041,6 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) */ if (cur_read_cost < best_read_cost - (DBL_EPSILON * cur_read_cost)) { - DBUG_ASSERT(tree != 0 || cur_param_idx == MAX_KEY); index_info= cur_index_info; index= cur_index; best_read_cost= cur_read_cost; @@ -8045,11 +8050,13 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree) best_param_idx= cur_param_idx; group_key_parts= cur_group_key_parts; group_prefix_len= cur_group_prefix_len; + key_infix_len= cur_key_infix_len; + if (key_infix_len) + memcpy (key_infix, cur_key_infix, sizeof (key_infix)); + used_key_parts= cur_used_key_parts; } - next_index: - cur_group_key_parts= 0; - cur_group_prefix_len= 0; + next_index:; } if (!index_info) /* No usable index found. */ DBUG_RETURN(NULL);