Commit 0b15557c authored by Sergei Petrunia's avatar Sergei Petrunia

MDEV-6796: Unable to skip filesort when using implicit extended key

Re-work test_if_order_by_key() to work correctly for extended indexes.
parent 15ad0d0b
......@@ -46,3 +46,45 @@ EXPLAIN SELECT * FROM t2 WHERE pk1=9 AND fd5 < 500 ORDER B
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range PRIMARY,ux_pk1_fd5 ux_pk1_fd5 13 NULL 137 Using where
drop table t0,t1, t2;
#
# MDEV-6796: Unable to skip filesort when using implicit extended key
#
CREATE TABLE t1 (
pk1 int(11) NOT NULL,
pk2 varchar(64) NOT NULL,
col1 varchar(16) DEFAULT NULL,
PRIMARY KEY (pk1,pk2),
KEY key1 (pk1,col1)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE t2 (
pk1 int(11) NOT NULL,
pk2 varchar(64) NOT NULL,
col1 varchar(16) DEFAULT NULL,
PRIMARY KEY (pk1,pk2),
KEY key1 (pk1,col1,pk2)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `t1` VALUES
(12321321,'a8f5f167f44f4964e6c998dee827110c','video'),
(12321321,'d77a17a3659ffa60c54e0ea17b6c6d16','video'),
(12321321,'wwafdsafdsafads','video'),
(12321321,'696aa249f0738e8181957dd57c2d7d0b','video-2014-09-23'),
(12321321,'802f9f29584b486f356693e3aa4ef0af','video=sdsd'),
(12321321,'2f94543ff74aab82e9a058b4e8316d75','video=sdsdsds'),
(12321321,'c1316b9df0d203fd1b9035308de52a0a','video=sdsdsdsdsd');
insert into t2 select * from t1;
# this must not use filesort:
explain SELECT pk2
FROM t1 USE INDEX(key1)
WHERE pk1 = 123
AND col1 = 'video'
ORDER BY pk2 DESC LIMIT 21;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref key1 key1 55 const,const 1 Using where; Using index
# this must not use filesort, either:
explain SELECT pk2
FROM t2 USE INDEX(key1)
WHERE pk1 = 123 AND col1 = 'video'
ORDER BY pk2 DESC LIMIT 21;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref key1 key1 55 const,const 1 Using where; Using index
drop table t1, t2;
......@@ -41,3 +41,50 @@ EXPLAIN SELECT * FROM t2 USE INDEX(ux_pk1_fd5) WHERE pk1=9 AND fd5 < 500 ORDER B
EXPLAIN SELECT * FROM t2 WHERE pk1=9 AND fd5 < 500 ORDER BY fd5 DESC LIMIT 10;
drop table t0,t1, t2;
--echo #
--echo # MDEV-6796: Unable to skip filesort when using implicit extended key
--echo #
CREATE TABLE t1 (
pk1 int(11) NOT NULL,
pk2 varchar(64) NOT NULL,
col1 varchar(16) DEFAULT NULL,
PRIMARY KEY (pk1,pk2),
KEY key1 (pk1,col1)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE t2 (
pk1 int(11) NOT NULL,
pk2 varchar(64) NOT NULL,
col1 varchar(16) DEFAULT NULL,
PRIMARY KEY (pk1,pk2),
KEY key1 (pk1,col1,pk2)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `t1` VALUES
(12321321,'a8f5f167f44f4964e6c998dee827110c','video'),
(12321321,'d77a17a3659ffa60c54e0ea17b6c6d16','video'),
(12321321,'wwafdsafdsafads','video'),
(12321321,'696aa249f0738e8181957dd57c2d7d0b','video-2014-09-23'),
(12321321,'802f9f29584b486f356693e3aa4ef0af','video=sdsd'),
(12321321,'2f94543ff74aab82e9a058b4e8316d75','video=sdsdsds'),
(12321321,'c1316b9df0d203fd1b9035308de52a0a','video=sdsdsdsdsd');
insert into t2 select * from t1;
--echo # this must not use filesort:
explain SELECT pk2
FROM t1 USE INDEX(key1)
WHERE pk1 = 123
AND col1 = 'video'
ORDER BY pk2 DESC LIMIT 21;
--echo # this must not use filesort, either:
explain SELECT pk2
FROM t2 USE INDEX(key1)
WHERE pk1 = 123 AND col1 = 'video'
ORDER BY pk2 DESC LIMIT 21;
drop table t1, t2;
......@@ -281,6 +281,12 @@ public:
LEX_STRING comment;
/* Field is part of the following keys */
key_map key_start, part_of_key, part_of_key_not_clustered;
/*
Bitmap of indexes that have records ordered by col1, ... this_field, ...
For example, INDEX (col(prefix_n)) is not present in col.part_of_sortkey.
*/
key_map part_of_sortkey;
/*
We use three additional unireg types for TIMESTAMP to overcome limitation
......
......@@ -15044,6 +15044,11 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
@retval true can be used
@retval false cannot be used
*/
/*
psergey-todo: this returns false for int_column='1234' (here '1234' is a
constant. Need to discuss this with Bar).
*/
static bool
test_if_equality_guarantees_uniqueness(Item *l, Item *r)
{
......@@ -19676,12 +19681,21 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
{
KEY_PART_INFO *key_part,*key_part_end;
key_part=table->key_info[idx].key_part;
key_part_end=key_part+table->key_info[idx].user_defined_key_parts;
key_part_end=key_part + table->key_info[idx].ext_key_parts;
key_part_map const_key_parts=table->const_key_parts[idx];
uint user_defined_kp= table->key_info[idx].user_defined_key_parts;
int reverse=0;
uint key_parts;
my_bool on_pk_suffix= FALSE;
bool have_pk_suffix= false;
uint pk= table->s->primary_key;
DBUG_ENTER("test_if_order_by_key");
if ((table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
table->key_info[idx].ext_key_part_map &&
pk != MAX_KEY && pk != idx)
{
have_pk_suffix= true;
}
for (; order ; order=order->next, const_key_parts>>=1)
{
......@@ -19694,58 +19708,37 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
*/
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
/*
This check was in this function historically (although I think it's
better to check it outside of this function):
if (key_part >= key_part_end)
{
/*
We are at the end of the key. Check if the engine has the primary
key as a suffix to the secondary keys. If it has continue to check
the primary key as a suffix.
*/
if (!on_pk_suffix && (table->key_info[idx].ext_key_part_map & 1) &&
(table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
table->s->primary_key != MAX_KEY &&
table->s->primary_key != idx)
{
KEY_PART_INFO *start,*end;
uint pk_part_idx= 0;
on_pk_suffix= TRUE;
start= key_part= table->key_info[table->s->primary_key].key_part;
const_key_parts=table->const_key_parts[table->s->primary_key];
/*
Calculate true key_part_end and const_key_parts
(we have to stop as first not continous primary key part)
*/
for (key_part_end= key_part,
end= key_part+table->key_info[table->s->primary_key].user_defined_key_parts;
key_part_end < end; key_part_end++, pk_part_idx++)
{
/* Found hole in the pk_parts; Abort */
if (!(table->key_info[idx].ext_key_part_map &
(((key_part_map) 1) << pk_part_idx)))
break;
}
"Test if the primary key parts were all const (i.e. there's one row).
The sorting doesn't matter"
/* Adjust const_key_parts */
const_key_parts&= (((key_part_map) 1) << pk_part_idx) -1;
So, we're checking that
(1) this is an extended key
(2) we've reached its end
*/
key_parts= (key_part - table->key_info[idx].key_part);
if (have_pk_suffix &&
reverse == 0 && // all were =const so far
key_parts == table->key_info[idx].ext_key_parts &&
table->const_key_parts[pk] == PREV_BITS(uint,
table->key_info[pk].
user_defined_key_parts))
{
key_parts= 0;
reverse= 1; // Key is ok to use
goto ok;
}
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
/*
Test if the primary key parts were all const (i.e. there's one row).
The sorting doesn't matter.
*/
if (key_part == start+table->key_info[table->s->primary_key].user_defined_key_parts &&
reverse == 0)
{
key_parts= 0;
reverse= 1; // Key is ok to use
goto ok;
}
}
else
DBUG_RETURN(0);
if (key_part == key_part_end)
{
/*
There are some items left in ORDER BY that we don't
*/
DBUG_RETURN(0);
}
if (key_part->field != field || !field->part_of_sortkey.is_set(idx))
......@@ -19760,27 +19753,20 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
if (key_part < key_part_end)
key_part++;
}
if (on_pk_suffix)
{
uint used_key_parts_secondary= table->key_info[idx].user_defined_key_parts;
uint used_key_parts_pk=
(uint) (key_part - table->key_info[table->s->primary_key].key_part);
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
key_parts= (uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 &&
!(table->file->index_flags(idx, user_defined_kp, 1) & HA_READ_PREV))
reverse= 0; // Index can't be used
if (have_pk_suffix && reverse == -1)
{
key_parts= (uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 &&
!(table->file->index_flags(idx, key_parts-1, 1) & HA_READ_PREV))
uint pk_parts= table->key_info[pk].user_defined_key_parts;
if (!table->file->index_flags(pk, pk_parts, 1) & HA_READ_PREV)
reverse= 0; // Index can't be used
}
ok:
if (used_key_parts != NULL)
*used_key_parts= key_parts;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment