Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-4025

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

    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:
      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

            People

            • Assignee:
              igor Igor Babaev
              Reporter:
              igor Igor Babaev
            • Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: