diff options
| -rw-r--r-- | sql/opt_range.cc | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 11ba6c0e465..ca8f31f5775 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -175,7 +175,7 @@ static char is_null_string[2]= {1,0}; Example: By induction: Let's take any interval on some keypart in the middle: - kp15=1 + kp15=c0 Then let's AND it with this interval 'structure' from preceding and following keyparts: @@ -184,18 +184,18 @@ static char is_null_string[2]= {1,0}; We will obtain this SEL_ARG graph: - kp14 $ kp15 $ kp16 - $ $ - +---------+ $ +--------+ $ +---------+ - | kp14=c1 |--$-->| kp15=1 |--$-->| kp16=c3 | - +---------+ $ +--------+ $ +---------+ - | $ $ - +---------+ $ +--------+ $ - | kp14=c2 |--$-->| kp15=1 | $ - +---------+ $ +--------+ $ - $ $ + kp14 $ kp15 $ kp16 + $ $ + +---------+ $ +---------+ $ +---------+ + | kp14=c1 |--$-->| kp15=c0 |--$-->| kp16=c3 | + +---------+ $ +---------+ $ +---------+ + | $ $ + +---------+ $ +---------+ $ + | kp14=c2 |--$-->| kp15=c0 | $ + +---------+ $ +---------+ $ + $ $ - Note that we had to duplicate "kp15=1" and there was no way to avoid + Note that we had to duplicate "kp15=c0" and there was no way to avoid that. The induction step: AND the obtained expression with another "wrapping" expression like (*). @@ -477,7 +477,7 @@ typedef struct st_qsel_param { max_key[MAX_KEY_LENGTH+MAX_FIELD_WIDTH]; bool quick; // Don't calulate possible keys COND *cond; - /* Numbr of SEL_ARG objects allocated by SEL_ARG::clone_tree operations */ + /* Number of SEL_ARG objects allocated by SEL_ARG::clone_tree operations */ uint alloced_sel_args; } PARAM; @@ -681,7 +681,8 @@ SEL_ARG *SEL_ARG::clone(PARAM *param, SEL_ARG *new_parent, SEL_ARG **next_arg) tmp->parent=new_parent; tmp->next_key_part=next_key_part; if (left != &null_element) - tmp->left=left->clone(param, tmp, next_arg); + if (!(tmp->left=left->clone(param, tmp, next_arg))) + return 0; // OOM tmp->prev= *next_arg; // Link into next/prev chain (*next_arg)->next=tmp; |