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  1. MariaDB Server
  2. MDEV-11307

sum() and avg() return incorrect result for float when calculation overflows float range

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Details

    • Bug
    • Status: Confirmed (View Workflow)
    • Major
    • Resolution: Unresolved
    • 5.5, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 10.10
    • 10.4, 10.5, 10.6
    • None
    • CentOS x86_64

    Description

      I believe MCOL-148 is the same issue and is not restricted to the InfiniDB use case.

      – Create table

      DROP TABLE IF EXISTS `inno_1`;
      CREATE TABLE `inno_1` (
        `uINT` int unsigned DEFAULT NULL,
        `uDECIMAL_65_30` decimal(65,30) unsigned DEFAULT NULL
      ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
      INSERT INTO `inno_1` VALUES
      (1,34750000000000003551216178095456255.999999999999999999999999999738),
      (1,26750000000000003986614330199113727.999999999999999999999999999706),
      (1,32750000000000003660065716121370623.999999999999999999999999999730),
      (1,77250000000000001238163495044775935.999999999999999999999999999908);
      

      – Compare results of query (incorrect result)

      SELECT uINT,avg(uDECIMAL_65_30) FROM inno_1 GROUP BY uINT;
      -- With (correct result):
      SELECT avg(uDECIMAL_65_30) FROM inno_1;
       
      MariaDB [test]> SELECT uINT,avg(uDECIMAL_65_30) FROM inno_1 GROUP BY uINT;
      +------+--------------------------------------------------------------------+
      | uINT | avg(uDECIMAL_65_30)                                                |
      +------+--------------------------------------------------------------------+
      |    1 | 17875000000000003109014929865179135.999999999999999999999999999771 |
      +------+--------------------------------------------------------------------+
      1 row in set, 1 warning (0.00 sec)
       
      MariaDB [test]> show warnings;
      +---------+------+--------------------------------------------------------------+
      | Level   | Code | Message                                                      |
      +---------+------+--------------------------------------------------------------+
      | Warning | 1916 | Got overflow when converting '' to DECIMAL. Value truncated. |
      +---------+------+--------------------------------------------------------------+
      1 row in set (0.00 sec)
      

      Vs.

      MariaDB [test]> SELECT avg(uDECIMAL_65_30) FROM inno_1;
      +--------------------------------------------------------------------+
      | avg(uDECIMAL_65_30)                                                |
      +--------------------------------------------------------------------+
      | 42875000000000003109014929865179135.999999999999999999999999999771 |
      +--------------------------------------------------------------------+
      1 row in set (0.00 sec)
      

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              Unassigned Unassigned
              ashwing Ashwin Gopalakrishnan
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              Dates

                Created:
                Updated:

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