diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index c7af4a37e9a..d905516b075 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -10859,6 +10859,9 @@ finish: acceptable, as this happens rarely. The implementation without copying would be much more complicated. + For description of how equality propagation works with SJM nests, grep + for EqualityPropagationAndSjmNests. + @param left_item left term of the quality to be checked @param right_item right term of the equality to be checked @param item equality item if the equality originates from a condition @@ -10932,12 +10935,14 @@ static bool check_simple_equality(Item *left_item, Item *right_item, { /* left_item_equal of an upper level contains left_item */ left_item_equal= new Item_equal(left_item_equal); + left_item_equal->set_context_field(((Item_field*) left_item)); cond_equal->current_level.push_back(left_item_equal); } if (right_copyfl) { /* right_item_equal of an upper level contains right_item */ right_item_equal= new Item_equal(right_item_equal); + right_item_equal->set_context_field(((Item_field*) right_item)); cond_equal->current_level.push_back(right_item_equal); } @@ -10967,6 +10972,7 @@ static bool check_simple_equality(Item *left_item, Item *right_item, Item_equal *item_equal= new Item_equal(orig_left_item, orig_right_item, FALSE); + item_equal->set_context_field((Item_field*)left_item); cond_equal->current_level.push_back(item_equal); } } @@ -11023,6 +11029,7 @@ static bool check_simple_equality(Item *left_item, Item *right_item, { item_equal= new Item_equal(item_equal); cond_equal->current_level.push_back(item_equal); + item_equal->set_context_field(field_item); } if (item_equal) { @@ -11036,6 +11043,7 @@ static bool check_simple_equality(Item *left_item, Item *right_item, else { item_equal= new Item_equal(const_item, orig_field_item, TRUE); + item_equal->set_context_field(field_item); cond_equal->current_level.push_back(item_equal); } return TRUE; @@ -11672,6 +11680,8 @@ static TABLE_LIST* embedding_sjm(Item *item) Item_equal::get_first() also takes similar measures for dealing with equality substitution in presense of SJM nests. + Grep for EqualityPropagationAndSjmNests for a more verbose description. + @return - The condition with generated simple equalities or a pointer to the simple generated equality, if success. @@ -11735,9 +11745,13 @@ Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels, on upper AND-levels. */ if (upper) - { + { + TABLE_LIST *native_sjm= embedding_sjm(item_equal->context_field); if (item_const && upper->get_const()) + { + /* Upper item also has "field_item=const". Don't produce equality here */ item= 0; + } else { Item_equal_fields_iterator li(*item_equal); @@ -11748,6 +11762,8 @@ Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels, break; } } + if (embedding_sjm(field_item) != native_sjm) + item= NULL; /* Don't produce equality */ } bool produce_equality= test(item == field_item); |