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This commit is contained in:
Sergey Petrunia
2008-07-17 22:28:42 +04:00
parent 6cac08bcfb 7f16afccfb
commit 19e2ed7642
5 changed files with 70 additions and 62 deletions
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66
sql/opt_range.cc
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@ -8560,7 +8560,8 @@ bool QUICK_RANGE_SELECT::row_in_ranges()
QUICK_SELECT_DESC::QUICK_SELECT_DESC(QUICK_RANGE_SELECT *q,
uint used_key_parts_arg)
:QUICK_RANGE_SELECT(*q), rev_it(rev_ranges)
:QUICK_RANGE_SELECT(*q), rev_it(rev_ranges),
used_key_parts (used_key_parts_arg)
{
QUICK_RANGE *r;
@ -8602,10 +8603,11 @@ int QUICK_SELECT_DESC::get_next()
int result;
if (last_range)
{ // Already read through key
result = ((last_range->flag & EQ_RANGE)
? file->index_next_same(record, last_range->min_key,
last_range->min_length) :
file->index_prev(record));
result = ((last_range->flag & EQ_RANGE &&
used_key_parts <= head->key_info[index].key_parts) ?
file->index_next_same(record, last_range->min_key,
last_range->min_length) :
file->index_prev(record));
if (!result)
{
if (cmp_prev(*rev_it.ref()) == 0)
@ -8629,7 +8631,9 @@ int QUICK_SELECT_DESC::get_next()
continue;
}
if (last_range->flag & EQ_RANGE)
if (last_range->flag & EQ_RANGE &&
used_key_parts <= head->key_info[index].key_parts)
{
result = file->index_read_map(record, last_range->max_key,
last_range->max_keypart_map,
@ -8638,6 +8642,8 @@ int QUICK_SELECT_DESC::get_next()
else
{
DBUG_ASSERT(last_range->flag & NEAR_MAX ||
(last_range->flag & EQ_RANGE &&
used_key_parts > head->key_info[index].key_parts) ||
range_reads_after_key(last_range));
result=file->index_read_map(record, last_range->max_key,
last_range->max_keypart_map,
@ -8735,54 +8741,6 @@ bool QUICK_SELECT_DESC::range_reads_after_key(QUICK_RANGE *range_arg)
}
/* TRUE if we are reading over a key that may have a NULL value */
#ifdef NOT_USED
bool QUICK_SELECT_DESC::test_if_null_range(QUICK_RANGE *range_arg,
uint used_key_parts)
{
uint offset, end;
KEY_PART *key_part = key_parts,
*key_part_end= key_part+used_key_parts;
for (offset= 0, end = min(range_arg->min_length, range_arg->max_length) ;
offset < end && key_part != key_part_end ;
offset+= key_part++->store_length)
{
if (!memcmp((char*) range_arg->min_key+offset,
(char*) range_arg->max_key+offset,
key_part->store_length))
continue;
if (key_part->null_bit && range_arg->min_key[offset])
return 1; // min_key is null and max_key isn't
// Range doesn't cover NULL. This is ok if there is no more null parts
break;
}
/*
If the next min_range is > NULL, then we can use this, even if
it's a NULL key
Example: SELECT * FROM t1 WHERE a = 2 AND b >0 ORDER BY a DESC,b DESC;
*/
if (key_part != key_part_end && key_part->null_bit)
{
if (offset >= range_arg->min_length || range_arg->min_key[offset])
return 1; // Could be null
key_part++;
}
/*
If any of the key parts used in the ORDER BY could be NULL, we can't
use the key to sort the data.
*/
for (; key_part != key_part_end ; key_part++)
if (key_part->null_bit)
return 1; // Covers null part
return 0;
}
#endif
void QUICK_RANGE_SELECT::add_info_string(String *str)
{
KEY *key_info= head->key_info + index;