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  1. #1
    Join Date
    Nov 2011
    Posts
    17

    Unanswered: query cache problem.....

    Hi,

    I am using workbench to know the status of the server and the query cache hit rate is 0.20 and key efficiency is 100% and the status variables are

    mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';
    +-------------------------+-----------+
    | Variable_name | Value |
    +-------------------------+-----------+
    | Qcache_free_blocks | 54 |
    | Qcache_free_memory | 26309232 |
    | Qcache_hits | 934615 |
    | Qcache_inserts | 454680839 |
    | Qcache_lowmem_prunes | 230756 |
    | Qcache_not_cached | 1700867 |
    | Qcache_queries_in_cache | 6167 |
    | Qcache_total_blocks | 12443 |
    +-------------------------+-----------+
    8 rows in set (0.00 sec)

    please help me in improving query cache hit rate????

  2. #2
    Join Date
    Sep 2009
    Location
    San Sebastian, Spain
    Posts
    880
    You are missing query_cache_limit. This parameter defines the maximum result set size stored in the query cache. If your Qcache_hits to Qcache_inserts is low (which it appears to be here) this can suggest that your query_cache_limit is too low and should be increased. All other parameters look good.
    Ronan Cashell
    Certified Oracle DBA/Certified MySQL Expert (DBA & Cluster DBA)
    http://www.it-iss.com
    Follow me on Twitter

  3. #3
    Join Date
    Nov 2011
    Posts
    17
    thanks Ronan,
    query_cache_limit variable is set to 1MB in my.cnf.Can it be increased to 2MB???

  4. #4
    Join Date
    Sep 2009
    Location
    San Sebastian, Spain
    Posts
    880
    Change it and see the results. If it still results in poor usage of query cache then increase it again.
    Ronan Cashell
    Certified Oracle DBA/Certified MySQL Expert (DBA & Cluster DBA)
    http://www.it-iss.com
    Follow me on Twitter

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