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  1. MariaDB Server
  2. MDEV-17846

Inconsistent results with optimizer_switch='derived_merge=ON/OFF';

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Details

    • Bug
    • Status: Confirmed (View Workflow)
    • Critical
    • Resolution: Unresolved
    • 10.3.11, 5.5(EOL), 10.0(EOL), 10.1(EOL), 10.2(EOL), 10.3(EOL), 10.4(EOL), 10.5, 10.6, 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL), 10.11
    • 10.5, 10.6
    • Optimizer
    • Redhat el6

    Description

      With the same select statement, it produces different results with optimizer_switch='derived_merge=ON'; and optimizer_switch='derived_merge=OFF';

      Reproduce test case:
      1. Follow the test_case.rtf attached, create table t1 and insert data into t1; create table t2 and insert data to t2.
      2. Set optimizer_switch='derived_merge=ON'; and run the select statement. It has empty set result.
      3. Set optimizer_switch='derived_merge=OFF'; and run the same select statement. It has result set:

      +--------------------+------------+ 
      | T_FP               | Test_Value | 
      +--------------------+------------+ 
      | 731834939448428685 |         22 | 
      +--------------------+------------+
      

      Thanks,

      KT Chow

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            monty Michael Widenius
            ktchow_ogcio Chow King Tak
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            Dates

              Created:
              Updated:

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