incorrect result when inlining CTE #52833
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affects-6.5
This bug affects the 6.5.x(LTS) versions.
affects-7.1
This bug affects the 7.1.x(LTS) versions.
affects-7.5
This bug affects the 7.5.x(LTS) versions.
affects-8.1
This bug affects the 8.1.x(LTS) versions.
fuzz/randomtest
severity/major
sig/sql-infra
SIG: SQL Infra
type/bug
The issue is confirmed as a bug.
Comments
ti-chi-bot
bot
added
may-affects-5.4
ti-chi-bot
added
affects-8.1
|
A smaller reproduce: CREATE TABLE
`t1` (
`col_5` json NOT NULL,
`col_7` date DEFAULT NULL
) ENGINE = InnoDB DEFAULT CHARSET = utf8 COLLATE = utf8_bin;
INSERT INTO
`t1`
VALUES
(
'[2]',
'2008-11-29'
);
CREATE TABLE
`t2` (
`col_5` json NOT NULL,
`col_7` date DEFAULT NULL
) ENGINE = InnoDB DEFAULT CHARSET = utf8 COLLATE = utf8_bin;
INSERT INTO
`t2`
VALUES
(
'[2]',
'2006-11-16'
);
WITH
`cte_3600` (`col_10746`) AS (
SELECT
EXPORT_SET (
3,
`t2`.`col_5`,
`t2`.`col_7`,
'-',
8
) AS `r0`
FROM
`t1`
JOIN `t2` ON `t1`.`col_5` = `t2`.`col_5`
) (
SELECT
1
FROM
`cte_3600`
WHERE
`cte_3600`.`col_10746` BETWEEN 'Wz%vodzG3' AND 'm*RzhE#Kif(H'
);I think the issue is that the internal expression SELECT
EXPORT_SET (
3,
`t2`.`col_5`,
`t2`.`col_7`,
'-',
8
) AS `r0`
FROM
`t1`
JOIN `t2` ON `t1`.`col_5` = `t2`.`col_5`The |
|
A smaller reproduce: SELECT EXPORT_SET (3,cast('[]' as json),'2','-',8) BETWEEN 'W' AND 'm';It gives |
|
MySQL has a strange function to set the string type: /**
Set the Item to be variable length string. Actual type is determined from
maximum string size. Collation must have been set before calling function.
@param max_l Maximum number of characters in string
*/
inline void set_data_type_string(uint32 max_l) {
max_length = max_l * collation.collation->mbmaxlen;
decimals = DECIMAL_NOT_SPECIFIED;
if (max_length <= Field::MAX_VARCHAR_WIDTH)
set_data_type(MYSQL_TYPE_VARCHAR);
else if (max_length <= Field::MAX_MEDIUM_BLOB_WIDTH)
set_data_type(MYSQL_TYPE_MEDIUM_BLOB);
else
set_data_type(MYSQL_TYPE_LONG_BLOB);
}The type of bool Item_func_export_set::resolve_type(THD *thd) {
if (param_type_is_default(thd, 0, 1, MYSQL_TYPE_LONGLONG)) return true;
if (param_type_is_default(thd, 1, 4)) return true;
if (param_type_is_default(thd, 4, 5, MYSQL_TYPE_LONGLONG)) return true;
if (agg_arg_charsets_for_string_result(collation, args + 1,
min(4U, arg_count) - 1))
return true;
const ulonglong length = max(args[1]->max_char_length(collation.collation),
args[2]->max_char_length(collation.collation));
const ulonglong sep_length =
(arg_count > 3 ? args[3]->max_char_length(collation.collation) : 1);
set_data_type_string(length * 64U + sep_length * 63U);
set_nullable(is_nullable() || max_length > thd->variables.max_allowed_packet);
return false;
}The problem is that, the /**
Set the data type of the Item to be JSON.
*/
void set_data_type_json() {
set_data_type(MYSQL_TYPE_JSON);
collation.set(&my_charset_utf8mb4_bin, DERIVATION_IMPLICIT);
decimals = DECIMAL_NOT_SPECIFIED;
max_length = Field::MAX_LONG_BLOB_WIDTH;
}As TiDB didn't have a unified |
|
Other incompatible cases: select concat(cast('[]' as json), '[]') between 'W' AND 'm';A lot of functions also have similar problem: |
13 tasks
YangKeao
added
severity/major
affects-6.5
ti-chi-bot
bot
added
may-affects-5.4
YangKeao
removed
may-affects-5.4
|
#53126 Fixed most of the situations. Not all functions mentioned above is included in this PR, because:
|
This was referenced May 11, 2024
terry1purcell
pushed a commit
to terry1purcell/tidb
that referenced
this issue
May 17, 2024
RidRisR
pushed a commit
to RidRisR/tidb
that referenced
this issue
May 23, 2024
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Bug Report
Please answer these questions before submitting your issue. Thanks!
1. Minimal reproduce step (Required)
2. What did you expect to see? (Required)
MySQL:
3. What did you see instead (Required)
TiDB
If disabled inlining CTE by referring cte_3600 one more time.
4. What is your TiDB version? (Required)
cfbabfa
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