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  1. MariaDB Server
  2. MDEV-4025

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

        Details

        • Type: Bug
        • Status: Open
        • Priority: Minor
        • Resolution: Unresolved
        • Affects Version/s: 5.3.11
        • Fix Version/s: 5.3.13
        • Component/s: None
        • Labels:
          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.

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                  • Assignee:
                    igor Igor Babaev
                    Reporter:
                    igor Igor Babaev
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                    Dates

                    • Created:
                      Updated: