MySQL Scheduling and Locking Issues

MySQL Scheduling and Locking Issues

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  1. Which table is preferred when there are many updates?










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: D

    The InnoDB tables can provide better performance when there are many updates. Locking is done at the row level rather than at the table level. So the extent of the table that is locked is smaller.

  1. The use of table level locks is always useful in MyISAM tables.










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: B

    MyISAM is extremely fast for retrievals but the use of table level locks can be a problem in environments with mixed retrievals and updates if the retrievals are long running.

  1. Find the odd one out in terms of scheduling policies.










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: D

    The InnoDB storage engine implements locking at a different level. It has differing performance characteristics in terms of contention management. It uses row-level locks.

  1. The number of tables for which DELAYED works is _________________.
    MyISAM, MEMORY, ARCHIVE, BLACKHOLE










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: A

    The ‘DELAYED’ statement modifier that influences the default scheduling policies of MySQL works for the following tables: MyISAM, MEMORY, ARCHIVE and as of MySQL 5.1.19, also for BLACKHOLE tables.

  1. The number of tables among the following for which HIGH_PRIORITY have an effect are _________________.
    MyISAM, MEMORY, MERGE










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: A

    In MySQL, the LOW_PRIORITY and HIGH_PRIORITY modifiers have an effect only for those storage engines that use table locks. The storage engines MyISAM, MERGE and MEMORY use table locks.