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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
View File

@ -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;

4
sql/opt_range.h
View File

@ -686,12 +686,10 @@ public:
int get_type() { return QS_TYPE_RANGE_DESC; }
private:
bool range_reads_after_key(QUICK_RANGE *range);
#ifdef NOT_USED
bool test_if_null_range(QUICK_RANGE *range, uint used_key_parts);
#endif
int reset(void) { rev_it.rewind(); return QUICK_RANGE_SELECT::reset(); }
List<QUICK_RANGE> rev_ranges;
List_iterator<QUICK_RANGE> rev_it;
uint used_key_parts;
};

29
sql/sql_select.cc
View File

@ -12508,6 +12508,9 @@ part_of_refkey(TABLE *table,Field *field)
@note
used_key_parts is set to correct key parts used if return value != 0
(On other cases, used_key_part may be changed)
Note that the value may actually be greater than the number of index
key parts. This can happen for storage engines that have the primary
key parts as a suffix for every secondary key.
@retval
1 key is ok.
@ -12580,11 +12583,27 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
reverse=flag; // Remember if reverse
key_part++;
}
*used_key_parts= on_primary_key ? table->key_info[idx].key_parts :
(uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) &
HA_READ_PREV))
reverse= 0; // Index can't be used
if (on_primary_key)
{
uint used_key_parts_secondary= table->key_info[idx].key_parts;
uint used_key_parts_pk=
(uint) (key_part - table->key_info[table->s->primary_key].key_part);
*used_key_parts= used_key_parts_pk + used_key_parts_secondary;
if (reverse == -1 &&
(!(table->file->index_flags(idx, used_key_parts_secondary - 1, 1) &
HA_READ_PREV) ||
!(table->file->index_flags(table->s->primary_key,
used_key_parts_pk - 1, 1) & HA_READ_PREV)))
reverse= 0; // Index can't be used
}
else
{
*used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 &&
!(table->file->index_flags(idx, *used_key_parts-1, 1) & HA_READ_PREV))
reverse= 0; // Index can't be used
}
DBUG_RETURN(reverse);
}