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  1. MariaDB ColumnStore
  2. MCOL-4728

Query with unusual use of aggregate functions on ColumnStore table crashes MariaDB Server

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 5.5.1
    • Fix Version/s: 6.2.1, 6.2.2
    • Component/s: None
    • Labels:
    • Sprint:
      2021-10, 2021-11

      Description

      A query was discovered that can kill the MariaDB process:

      MariaDB [nn]> alter table t engine='innodb';
      Query OK, 0 rows affected (0.118 sec)
      Records: 0  Duplicates: 0  Warnings: 0
       
      MariaDB [nn]> SELECT sum(0+0)-sum(0+0) from t;
      +-------------------+
      | sum(0+0)-sum(0+0) |
      +-------------------+
      |              NULL |
      +-------------------+
      1 row in set (0.000 sec)
       
      MariaDB [nn]> alter table t engine='columnstore';
      Query OK, 0 rows affected (0.094 sec)
      Records: 0  Duplicates: 0  Warnings: 0
       
      MariaDB [nn]> SELECT sum(0+0)-sum(0+0) from t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query
      MariaDB [nn]>
       
      Here are some variations on the same query:
      MariaDB [nn]> select sum(null) from t;
      +-----------+
      | sum(null) |
      +-----------+
      |      NULL |
      +-----------+
      1 row in set (0.042 sec)
       
      MariaDB [nn]> select sum(null)-sum(null) from t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query
       
      MariaDB [nn]> select avg(null)-avg(null) from t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query
      

      Looking in the mariadb.err file:

      210518 12:38:21 [ERROR] mysqld got signal 11 ;
      This could be because you hit a bug. It is also possible that this binary
      ...
      

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            Assignee:
            dleeyh Daniel Lee
            Reporter:
            edward Edward Stoever
            Votes:
            1 Vote for this issue
            Watchers:
            6 Start watching this issue

              Dates

              Created:
              Updated:
              Resolved:

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