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  1. MariaDB Server
  2. MDEV-4025

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

Details

    • Bug
    • Status: Closed (View Workflow)
    • Minor
    • Resolution: Fixed
    • 5.3.11
    • 5.3.12
    • Optimizer
    • None

    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.

      Attachments

        Activity

          igor Igor Babaev (Inactive) created issue -
          igor Igor Babaev (Inactive) made changes -
          Field Original Value New Value
          Description The following EXPLAIN command from the test case for LP bug #934348

          {code}
          EXPLAIN
          SELECT a FROM t1 t WHERE a IN (SELECT b FROM t1, t2 WHERE b = a)
          GROUP BY a HAVING a != 'z';
          {/code}
          returns
          {code}
          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
          ...
          {/code}
          It should return
          {code}
          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
          {/code}
          as the number of rows in the table t1 is equal to 3.

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

          {code}
          EXPLAIN
          SELECT a FROM t1 t WHERE a IN (SELECT b FROM t1, t2 WHERE b = a)
          GROUP BY a HAVING a != 'z';
          {code}
          returns
          {code}
          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
          ...
          {/code}
          It should return
          {code}
          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
          {/code}
          as the number of rows in the table t1 is equal to 3.

          igor Igor Babaev (Inactive) made changes -
          Description The following EXPLAIN command from the test case for LP bug #934348

          {code}
          EXPLAIN
          SELECT a FROM t1 t WHERE a IN (SELECT b FROM t1, t2 WHERE b = a)
          GROUP BY a HAVING a != 'z';
          {code}
          returns
          {code}
          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
          ...
          {/code}
          It should return
          {code}
          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
          {/code}
          as the number of rows in the table t1 is equal to 3.

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

          {code}
          EXPLAIN
          SELECT a FROM t1 t WHERE a IN (SELECT b FROM t1, t2 WHERE b = a)
          GROUP BY a HAVING a != 'z';
          {code}
          returns
          {code}
          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
          ...
          {code}
          It should return
          {code}
          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
          {code}
          as the number of rows in the table t1 is equal to 3.

          serg Sergei Golubchik made changes -
          Priority Major [ 3 ] Minor [ 4 ]
          serg Sergei Golubchik made changes -
          Fix Version/s 5.3.13 [ 12602 ]
          Fix Version/s 5.3.12 [ 12000 ]
          serg Sergei Golubchik made changes -
          Workflow defaullt [ 25805 ] MariaDB v2 [ 45963 ]
          ratzpo Rasmus Johansson (Inactive) made changes -
          Workflow MariaDB v2 [ 45963 ] MariaDB v3 [ 66649 ]
          serg Sergei Golubchik made changes -
          Assignee Igor Babaev [ igor ]
          elenst Elena Stepanova made changes -
          Component/s Optimizer [ 10200 ]
          Fix Version/s 5.3.12 [ 12000 ]
          Fix Version/s 5.3.13 [ 12602 ]
          Assignee Igor Babaev [ igor ]
          Resolution Fixed [ 1 ]
          Status Open [ 1 ] Closed [ 6 ]
          serg Sergei Golubchik made changes -
          Workflow MariaDB v3 [ 66649 ] MariaDB v4 [ 146323 ]

          People

            igor Igor Babaev (Inactive)
            igor Igor Babaev (Inactive)
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            Dates

              Created:
              Updated:
              Resolved:

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