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Fix ORDER BY ... DESC optimization

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This commit is contained in:
monty@hundin.mysql.fi
2001-06-29 04:04:29 +03:00
parent 545e596ef7
commit f0dc189227
7 changed files with 377 additions and 106 deletions
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10
sql/opt_range.h
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@ -54,9 +54,10 @@ class QUICK_RANGE :public Sql_alloc {
{}
};
class QUICK_SELECT {
public:
bool next;
bool next,dont_free;
int error;
uint index,max_used_key_length;
TABLE *head;
@ -80,16 +81,17 @@ public:
bool unique_key_range();
};
class QUICK_SELECT_DESC: public QUICK_SELECT
{
public:
QUICK_SELECT_DESC(QUICK_SELECT *q);
QUICK_SELECT_DESC(QUICK_SELECT *q, uint used_key_parts);
int get_next();
private:
int cmp_prev(QUICK_RANGE *range);
bool range_reads_after_key(QUICK_RANGE *range);
QUICK_SELECT *quick;
bool test_if_null_range(QUICK_RANGE *range, uint used_key_parts);
void reset(void) { next=0; rev_it.rewind(); }
List<QUICK_RANGE> rev_ranges;
List_iterator<QUICK_RANGE> rev_it;
};