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Sysadmin Mysqltuner ..questions

Discussion in 'System Administration' started by elargento, Sep 7, 2017.

  1. elargento

    elargento Member

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     MySQL started within last 24 hours - recommendations may be inaccurate
    Reduce your SELECT DISTINCT queries which have no LIMIT clause
        Performance should be activated for better diagnostics
        Consider installing Sys schema from https://github.com/mysql/mysql-sys
    Variables to adjust:
        query_cache_size (=0)
        query_cache_type (=0)
        query_cache_limit (> 1M, or use smaller result sets)
        tmp_table_size (> 16M)
        max_heap_table_size (> 16M)
        performance_schema = ON enable PFS
        innodb_buffer_pool_size (>= 4G) if possible.
        innodb_log_file_size should be (=16M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.
    
    Got the above results.

    How can I activate performance?
    Is it totally safe to install mysql-sys? Will that allow mysqltuner to access to more db usage details?

    mysql service is running more than 24 hours ago if I'm not wrong. Am I missing something?
    Is it enough to run it through perl like How to Optimize MySQL Performance Using MySQLTuner instructions?
     
  2. eva2000

    eva2000 Administrator Staff Member

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    Read official documentation and tutorials online for performance_schema and why it's recommended to disable normally due to performance overhead. It's catch 22, enabling it to monitor performance will in fact reduce performance itself. So read and understand what it does and decide if you want to enable. Centmin Mod disables it by default for performance reasons.
    read up on what it does and decide for yourself and better yet test on test VPS/local test server first GitHub - mysql/mysql-sys: The MySQL sys schema. Looks like it's made for Oracle MySQL 5.6 and 5.7 so some variables wouldn't match MariaDB 10.0/10.1/10.2+ so be careful Compatibility for MariaDB by Esysteme · Pull Request #99 · mysql/mysql-sys · GitHub

    mysqltuner output should say how long mysql has been running
     
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