[MDEV-3995] Wrong result with materialization, IN subquery, MyISAM. - Jira

Type: Bug
Status: Closed (View Workflow)
Priority: Major
Resolution: Fixed
Affects Version/s: 5.5.28a, 5.3.11
Fix Version/s: 5.5.30, 5.3.13
Component/s: None
Labels:
- optimizer
Environment:
RedHat EL6.3 x86_64 using 5.3.11 bintar and HEAD of lp:maria/5.3

Hello and thank you for mariadb-5.3.11-MariaDB-linux-x86_64,

This query:

SELECT

  count(*)

FROM

  wives, cats

WHERE

  cats.cat_id = wives.cat_id AND

  wives.cat_id IN (SELECT cat_id FROM kits) AND

  wives.sack_id = 33479 AND wives.kit_id = 6;

with materialization on returns 0, with it off returns 94.

Explain plan with materialization on:

+----+--------------+-------------+--------+---------------+--------------+---------+-------------------+------+--------------------------+

| id | select_type  | table       | type   | possible_keys | key          | key_len | ref               | rows | Extra                    |

+----+--------------+-------------+--------+---------------+--------------+---------+-------------------+------+--------------------------+

|  1 | PRIMARY      | wives       | index  | PRIMARY       | PRIMARY      | 9       | NULL              | 3690 | Using where; Using index |

|  1 | PRIMARY      | <subquery2> | eq_ref | distinct_key  | distinct_key | 4       | func              |    1 | Using where              |

|  1 | PRIMARY      | cats        | eq_ref | PRIMARY       | PRIMARY      | 4       | test2.kits.cat_id |    1 | Using where; Using index |

|  2 | MATERIALIZED | kits        | index  | cat_id        | cat_id       | 4       | NULL              | 7578 | Using index              |

+----+--------------+-------------+--------+---------------+--------------+---------+-------------------+------+--------------------------+

Schema and data attached (4MB). I tested with 5.3.11 and the HEAD of lp:maria/5.3

Thank you.

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