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Mysql DB Optimization

Discussion in 'Workarounds and Optimization' started by keerti.rastogi, Sep 12, 2014.

  1. keerti.rastogi

    keerti.rastogi Registered

    Sep 12, 2014
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    Hello All,

    I am using AWS M3.2xlarge instance for a Moodle 2.4 site, but for the last few days we are observing very high cpu usage on server when traffic is high. So I have used script to examine me server & database, below are the results for same -

    >>  MySQLTuner 1.3.0 - Major Hayden <>
     >>  Bug reports, feature requests, and downloads at [url=]MySQLTuner-perl by major[/url]
     >>  Run with '--help' for additional options and output filtering
    [[0;34m--[0m] Performing tests on
    [[0;34m--[0m] Assuming 30000 MB of physical memory
    [[0;31m!![0m] Assuming 0 MB of swap space (use --forceswap to specify)
    [[0;32mOK[0m] Currently running supported MySQL version 5.5.31-log
    -------- Storage Engine Statistics -------------------------------------------
    [[0;34m--[0m] Status: [0;32m+ARCHIVE [0m[0;32m+BLACKHOLE [0m[0;32m+CSV [0m[0;31m-FEDERATED [0m[0;32m+InnoDB [0m[0;32m+MRG_MYISAM [0m
    [[0;34m--[0m] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
    [[0;34m--[0m] Data in InnoDB tables: 11G (Tables: 663)
    [[0;34m--[0m] Data in MyISAM tables: 30M (Tables: 17)
    [[0;31m!![0m] Total fragmented tables: 60
    -------- Security Recommendations  -------------------------------------------
    [[0;32mOK[0m] All database users have passwords assigned
    -------- Performance Metrics -------------------------------------------------
    [[0;34m--[0m] Up for: 27d 0h 18m 35s (183M q [78.458 qps], 1M conn, TX: 7680B, RX: 112B)
    [[0;34m--[0m] Reads / Writes: 71% / 29%
    [[0;34m--[0m] Total buffers: 15.3G global + 3.9M per thread (2836 max threads)
    [[0;31m!![0m] Maximum possible memory usage: 26.0G (88% of installed RAM)
    [[0;32mOK[0m] Slow queries: 0% (11K/183M)
    [[0;32mOK[0m] Highest usage of available connections: 8% (254/2836)
    [[0;32mOK[0m] Key buffer size / total MyISAM indexes: 128.0M/29.1M
    [[0;32mOK[0m] Key buffer hit rate: 99.8% (4M cached / 7K reads)
    [[0;32mOK[0m] Query cache efficiency: 75.3% (121M cached / 160M selects)
    [[0;31m!![0m] Query cache prunes per day: 180978
    [[0;32mOK[0m] Sorts requiring temporary tables: 0% (2K temp sorts / 11M sorts)
    [[0;31m!![0m] Joins performed without indexes: 74090
    [[0;32mOK[0m] Temporary tables created on disk: 11% (804K on disk / 6M total)
    [[0;32mOK[0m] Thread cache hit rate: 99% (254 created / 1M connections)
    [[0;31m!![0m] Table cache hit rate: 0% (400 open / 2M opened)
    [[0;32mOK[0m] Open file limit used: 0% (53/65K)
    [[0;32mOK[0m] Table locks acquired immediately: 99% (61M immediate / 61M locks)
    [[0;32mOK[0m] InnoDB buffer pool / data size: 15.0G/11.0G
    [[0;32mOK[0m] InnoDB log waits: 0
    -------- Recommendations -----------------------------------------------------
    General recommendations:
        Run OPTIMIZE TABLE to defragment tables for better performance
        Reduce your overall MySQL memory footprint for system stability
        Adjust your join queries to always utilize indexes
        Increase table_open_cache gradually to avoid file descriptor limits
        Read this before increasing table_open_cache over 64: [url=]table_cache negative scalability - MySQL Performance Blog[/url]
    Variables to adjust:
        query_cache_size (> 128M)
        join_buffer_size (> 128.0K, or always use indexes with joins)
        table_open_cache (> 400)

    Below are few parameters from mysql configurations -

    log_slow_queries	        ON
    slow_query_log	                ON
    slow_query_log_file	        /rdsdbdata/log/slowquery/mysql-slowquery.log
    long_query_time	                10.000000
    max_connections	        2836
    max_user_connections	0
    query_cache_type	        ON
    query_cache_limit	        16777216
    query_cache_size	        134217728
    join_buffer_size	                131072
    read_rnd_buffer_size	        524288
    max_allowed_packet	        134217728
    tmp_table_size	                16777216
    max_heap_table_size 	16777216
    table_open_cache	        400
    thread_cache_size	        300
    open_files_limit	                65535
    key_buffer_size	                134217728
    myisam_sort_buffer_size	8388608
    innodb_file_per_table	        ON
    innodb_buffer_pool_size	16106127360 
    innodb_log_file_size	        134217728
    We are working to examine the fragmented tables in our database and fixing them. But, it would be great if any one can suggest other areas/parameters, where do we need to improvements. Let me know if any other information is required.

    Great Thanks in advance !! :)
  2. cPanelMichael

    cPanelMichael Technical Support Community Manager Staff Member

    Apr 11, 2011
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