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MDEV-6105: Emoji unicode character string search query makes mariadb performance down

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- When range optimizer cannot the lookup value into [VAR]CHAR(n) column,
  it should produce:
  = "Impossible range" for equality
  = "no range" for non-equalities.
This commit is contained in:
Sergey Petrunya 2014-06-05 19:18:35 +04:00
parent 7d3a67a976
commit c7e5a1f70d
3 changed files with 103 additions and 0 deletions
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54
mysql-test/r/range.result
View File

@ -2046,3 +2046,57 @@ f1 f2 f3 f4
10 0 0 0
DROP TABLE t1;
DROP VIEW v3;
#
# MDEV-6105: Emoji unicode character string search query makes mariadb performance down
#
SET NAMES utf8;
DROP TABLE IF EXISTS t1;
Warnings:
Note 1051 Unknown table 't1'
CREATE TABLE t1(
id int AUTO_INCREMENT,
fd varchar(20),
primary key(id),
index ix_fd(fd)
)engine=innodb default charset=UTF8;
INSERT INTO t1(id, fd) VALUES (null, ''),(null, 'matt'),(null, 'pitt'),(null, 'lee'),(null, 'kim');
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
# The following should show "Impossible WHERE" :
explain
SELECT * FROM t1 WHERE fd='😁';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
Warnings:
Warning 1366 Incorrect string value: '\xF0\x9F\x98\x81' for column 'fd' at row 1
SELECT * FROM t1 WHERE fd='😁';
id fd
Warnings:
Warning 1366 Incorrect string value: '\xF0\x9F\x98\x81' for column 'fd' at row 1
# The following must not use range access:
explain select count(*) from t1 where fd <'😁';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index ix_fd ix_fd 63 NULL 41410 Using where; Using index
Warnings:
Warning 1366 Incorrect string value: '\xF0\x9F\x98\x81' for column 'fd' at row 1
select count(*) from t1 where fd <'😁';
count(*)
40960
Warnings:
Warning 1366 Incorrect string value: '\xF0\x9F\x98\x81' for column 'fd' at row 1
select count(*) from t1 ignore index (ix_fd) where fd <'😁';
count(*)
40960
drop table t1;
set names default;

38
mysql-test/t/range.test
View File

@ -1638,3 +1638,41 @@ UPDATE v3 SET f3=0, f4=4 WHERE f2=68 ORDER BY f1;
SELECT * FROM v3;
DROP TABLE t1;
DROP VIEW v3;
--echo #
--echo # MDEV-6105: Emoji unicode character string search query makes mariadb performance down
--echo #
SET NAMES utf8;
DROP TABLE IF EXISTS t1;
CREATE TABLE t1(
id int AUTO_INCREMENT,
fd varchar(20),
primary key(id),
index ix_fd(fd)
)engine=innodb default charset=UTF8;
INSERT INTO t1(id, fd) VALUES (null, ''),(null, 'matt'),(null, 'pitt'),(null, 'lee'),(null, 'kim');
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
INSERT INTO t1 (fd) SELECT fd FROM t1;
--echo # The following should show "Impossible WHERE" :
explain
SELECT * FROM t1 WHERE fd='😁';
SELECT * FROM t1 WHERE fd='😁';
--echo # The following must not use range access:
explain select count(*) from t1 where fd <'😁';
select count(*) from t1 where fd <'😁';
select count(*) from t1 ignore index (ix_fd) where fd <'😁';
drop table t1;
set names default;

11
sql/opt_range.cc
View File

@ -7775,6 +7775,17 @@ get_mm_leaf(RANGE_OPT_PARAM *param, COND *conf_func, Field *field,
if (field->cmp_type() == STRING_RESULT && value->cmp_type() != STRING_RESULT)
goto end;
err= value->save_in_field_no_warnings(field, 1);
if (err == 2 && field->cmp_type() == STRING_RESULT)
{
if (type == Item_func::EQ_FUNC)
{
tree= new (alloc) SEL_ARG(field, 0, 0);
tree->type= SEL_ARG::IMPOSSIBLE;
}
else
tree= NULL; /* Cannot infer anything */
goto end;
}
if (err > 0)
{
if (field->cmp_type() != value->result_type())