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MDEV-10325: Queries examines all rows of a tables when it should not

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The problem was introduced by 1859caf60b:
  MDEV-10175: range optimizer calls records_in_range() for full extended keys

  Make the range optimizer not call records_in_range() when it would
  not give any benefit.

that patch used an incorrect way to check for full extended key. Now fixing
the check.
This commit is contained in:
Sergei Petrunia
2016-07-11 22:01:24 +03:00
parent 53e7fcca41
commit 0bb5d95542
3 changed files with 55 additions and 3 deletions
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24
mysql-test/r/innodb_ext_key.result
View File

@ -1040,5 +1040,29 @@ a
1
drop table t1, t2;
set optimizer_switch=@save_optimizer_switch;
#
# MDEV-10325: Queries examines all rows of a tables when it should not
#
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (
pk int not null,
col1 varchar(32),
filler varchar(100),
key idx1(col1(10)),
primary key (pk)
)engine=innodb;
insert into t1
select
A.a + 10*B.a + 100*C.a,
concat('1234567890-', 1000+ A.a + 10*B.a + 100*C.a),
repeat('filler-data-', 4)
from
t0 A, t0 B, t0 C;
# The following must use type=ALL (and NOT type=ref, rows=1)
explain select * from t1 where col1='1234567890-a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL idx1 NULL NULL NULL # Using where
drop table t0,t1;
set optimizer_switch=@save_ext_key_optimizer_switch;
SET SESSION STORAGE_ENGINE=DEFAULT;

28
mysql-test/t/innodb_ext_key.test
View File

@ -693,5 +693,33 @@ drop table t1, t2;
set optimizer_switch=@save_optimizer_switch;
--echo #
--echo # MDEV-10325: Queries examines all rows of a tables when it should not
--echo #
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (
pk int not null,
col1 varchar(32),
filler varchar(100),
key idx1(col1(10)),
primary key (pk)
)engine=innodb;
insert into t1
select
A.a + 10*B.a + 100*C.a,
concat('1234567890-', 1000+ A.a + 10*B.a + 100*C.a),
repeat('filler-data-', 4)
from
t0 A, t0 B, t0 C;
--echo # The following must use type=ALL (and NOT type=ref, rows=1)
--replace_column 9 #
explain select * from t1 where col1='1234567890-a';
drop table t0,t1;
set optimizer_switch=@save_ext_key_optimizer_switch;
SET SESSION STORAGE_ENGINE=DEFAULT;

6
sql/opt_range_mrr.cc
View File

@ -278,14 +278,14 @@ walk_up_n_right:
(1) - range analysis is used for estimating condition selectivity
(2) - This is a unique key, and we have conditions for all its
user-defined key parts.
(3) - The table uses extended keys, and we have conditions for
all key parts.
(3) - The table uses extended keys, this key covers all components,
and we have conditions for all key parts.
*/
if (!(cur->min_key_flag & ~NULL_RANGE) && !cur->max_key_flag &&
(!key_info || // (1)
((uint)key_tree->part+1 == key_info->user_defined_key_parts && // (2)
key_info->flags & HA_NOSAME) || // (2)
(seq->param->table->s->use_ext_keys && // (3)
((key_info->flags & HA_EXT_NOSAME) && // (3)
(uint)key_tree->part+1 == key_info->ext_key_parts) // (3)
) &&
range->start_key.length == range->end_key.length &&