diff options
| -rw-r--r-- | sql/opt_range.cc | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 9604ed1e3b3..b8f583a66ed 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -5345,6 +5345,34 @@ static SEL_TREE *get_func_mm_tree(RANGE_OPT_PARAM *param, Item_func *cond_func, { new_interval->min_value= last_val->max_value; new_interval->min_flag= NEAR_MIN; + + /* + If the interval is over a partial keypart, the + interval must be "c_{i-1} <= X < c_i" instead of + "c_{i-1} < X < c_i". Reason: + + Consider a table with a column "my_col VARCHAR(3)", + and an index with definition + "INDEX my_idx my_col(1)". If the table contains rows + with my_col values "f" and "foo", the index will not + distinguish the two rows. + + Note that tree_or() below will effectively merge + this range with the range created for c_{i-1} and + we'll eventually end up with only one range: + "NULL < X". + + Partitioning indexes are never partial. + */ + if (param->using_real_indexes) + { + const KEY key= + param->table->key_info[param->real_keynr[idx]]; + const KEY_PART_INFO *kpi= key.key_part + new_interval->part; + + if (kpi->key_part_flag & HA_PART_KEY_SEG) + new_interval->min_flag= 0; + } } } /* @@ -5827,6 +5855,7 @@ get_mm_leaf(RANGE_OPT_PARAM *param, COND *conf_func, Field *field, if (key_part->image_type == Field::itMBR) { + // @todo: use is_spatial_operator() instead? switch (type) { case Item_func::SP_EQUALS_FUNC: case Item_func::SP_DISJOINT_FUNC: |