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  1. MariaDB Server
  2. MDEV-6026

MySQL Bug #11757397 49437: CANNOT DO SHOW FIELDS FOR BIG VIEW

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    Details

    • Type: Bug
    • Status: Open (View Workflow)
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: 10.0.10
    • Fix Version/s: 10.0
    • Component/s: None
    • Labels:
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      Description

      Test case for MySQL "Bug #11757397 49437: CANNOT DO SHOW FIELDS FOR BIG VIEW" fails in 10.0. Please check if the problem affects MariaDB: it could have been fixed differently.

      revno: 3256
      committer: Jon Olav Hauglid <jon.hauglid@oracle.com>
      branch nick: mysql-trunk-bug11757397
      timestamp: Wed 2011-07-13 12:29:51 +0200
      message:
        Bug #11757397 49437: CANNOT DO SHOW FIELDS FOR BIG VIEW
       
        The problem was that views with too many columns in some
        cases would appear to work correctly, while in other cases gave
        various error messages. For example, DESCRIBE and SHOW commands
        could give "Incorrect key file for table..." errors.
       
        Depending on column datatypes used, views are materialized
        as either MyISAM or Memory internal temporary tables.
        The root cause of the problem was that MyISAM tables support
        a limited number of columns. This is due too a 64K file header
        size limitation. This limitation was not checked by CREATE VIEW.
        Therefore views with unsupported sizes could be made, leading to
        various errors when the view was later used.
       
        This patch fixes the problem by reporting ER_TOO_MANY_FIELDS
        error ("Too many columns") if views with more than 4096 columns
        are created. Thus ensuring that any MyISAM table which might
        be created for view processing will fit into the 64K header limit.
        Note that 4096 was chosen as limit as this number is already the
        limit on the number of columns for base tables.
       
        Test case added to view.test.

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              Assignee:
              Unassigned
              Reporter:
              svoj Sergey Vojtovich
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                Created:
                Updated: