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  1. MariaDB Server
  2. MDEV-4854

ConnectSE: table_type=mysql does not send the WHERE part -> full table scan

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Not a Bug
    • 10.0.3
    • 10.0.5
    • None
    • Ubuntu/Precise/LXContainer

    Description

      ConnectSE does not send the WHERE part of an statement in opposite to the docs (https://kb.askmonty.org/en/connect-table-types-mysql-table-type-accessing-mysqlmariadb-tables/) to the remote server.
      Given:

      CREATE TABLE `federatedconnect` (
        `id` int(11) NOT NULL,
        `id2` int(11) DEFAULT NULL
      ) ENGINE=CONNECT DEFAULT CHARSET=latin1 `TABLE_TYPE`='mysql' `TABNAME`='aha' `DBNAME`='test' `OPTION_LIST`='user=me,host=10.0.3.191'

      Regarding to the docs select * from federatedconnect where id=1 should be sent as: SELECT id,id2 FROM aha WHERE id=1 to the remote server.
      Using ngrep I see only: SELECT `id`, `id2` FROM `aha` So all rows are send instead of only one.
      The table aha has about 1000 rows. So even another 'proof'.

      MariaDB [test]> show status like 'handler_read_rnd_next'; select * from federate_classic where id=1;  show status like 'handler_read_rnd_next';
      +-----------------------+-------+
      | Variable_name         | Value |
      +-----------------------+-------+
      | Handler_read_rnd_next | 7347  |
      +-----------------------+-------+
      1 row in set (0.00 sec)
       
      +------+------+
      | id   | id2  |
      +------+------+
      |    1 |    4 |
      +------+------+
      1 row in set (0.00 sec)
       
      +-----------------------+-------+
      | Variable_name         | Value |
      +-----------------------+-------+
      | Handler_read_rnd_next | 8356  |
      +-----------------------+-------+
      1 row in set (0.00 sec)
       

      So we see all rows are send.

      Regads
      Erkan

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            bertrandop Olivier Bertrand
            erkules erkan yanar
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              Created:
              Updated:
              Resolved:

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