Re: bk commit into 5.0 tree (kaa:1.2606) BUG#35298

[Alexey Kopytov]

Hi Sergey,

Sergey Petrunia wrote:
> Hi,
> 
> On Thu, Apr 17, 2008 at 11:18:50AM +0400, Alexey Kopytov wrote:
>> diff -Nrup a/mysql-test/t/func_gconcat.test b/mysql-test/t/func_gconcat.test
>> --- a/mysql-test/t/func_gconcat.test	2008-02-28 14:31:18 +03:00
>> +++ b/mysql-test/t/func_gconcat.test	2008-04-17 11:18:45 +04:00
>> @@ -657,4 +657,40 @@ SELECT s1.d1 FROM
>>  ) AS s1;
>>  DROP TABLE t1;
>>  
>> +#
>> +# Bug #35298: GROUP_CONCAT with DISTINCT can crash the server
>> +#
>> +
>> +CREATE TABLE t1 (a INT);
>> +CREATE TABLE t2 (a INT);
>> +
>> +INSERT INTO t1 VALUES(1);
>> +
>> +SELECT GROUP_CONCAT(DISTINCT t2.a) FROM t1 LEFT JOIN t2 ON t2.a = t1.a GROUP BY
> t1.a;
>> +
>> +DROP TABLE t1, t2;
>> +
>> +#
>> +# Bug #36024: group_concat distinct in subquery crash
>> +#
>> +
>> +CREATE TABLE t1 (a INT);
>> +CREATE TABLE t2 (b INT);
>> +
>> +INSERT INTO t1 VALUES (NULL), (8), (2);
>> +INSERT INTO t2 VALUES (4), (10);
>> +
>> +SELECT 1 FROM t1 WHERE t1.a NOT IN
>> +(
>> +  SELECT GROUP_CONCAT(DISTINCT t1.a)
>> +  FROM  t1 WHERE t1.a IN   
>> +  (
>> +    SELECT b FROM t2
>> +  ) 
>> +  AND NOT t1.a >= (SELECT t1.a FROM t1 LIMIT 1)
>> +  GROUP BY t1.a
>> +);
>> +
>> +DROP TABLE t1, t2;
>> +
>>  --echo End of 5.0 tests
> The commited testcase doesn't demonstrate the problem, for it we have 
>  
>   distinct!=NULL && unique!=NULL 
> 
> at all times. Please use the test case provided by the bug reporter. it 
> has COUNT(DISTINCT const_column_that_is_always_null) for which we really 
> can have (distinct=TRUE && unique_filter==NULL)
> 
> Ok to push after the above is addressed.
> 
> BR
>  Sergey


I just omitted KEY specification from t1 in the second test case for 
brevity. Adding it back leads to unique == NULL with a non-zero 
distinct. Good catch!

Thanks and regards,

-- 
Alexey Kopytov, Software Developer
MySQL AB, www.mysql.com

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