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  1. MariaDB Server
  2. MDEV-4025

Wrong estimate of rows in the test case for LP bug #934348

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: 5.3.11
    • Fix Version/s: 5.3.12
    • Component/s: Optimizer
    • Labels:
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      Description

      The following EXPLAIN command from the test case for LP bug #934348

      EXPLAIN
      SELECT a FROM t1 t WHERE a IN (SELECT b FROM t1, t2 WHERE b = a)
      GROUP BY a HAVING a != 'z';

      returns

      id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
      1	PRIMARY	t	index	idx_a	idx_a	4	NULL	1	Using index
      ...

      It should return

      id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
      1	PRIMARY	t	index	idx_a	idx_a	4	NULL	3	Using index

      as the number of rows in the table t1 is equal to 3.

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            Assignee:
            igor Igor Babaev
            Reporter:
            igor Igor Babaev
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              Dates

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              Updated:
              Resolved: