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mysql CPU usage too high

Discussion in 'Workarounds and Optimization' started by harivaag, Nov 25, 2013.

  1. harivaag

    harivaag Registered

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    Hi All,


    my cpu load is always high and my LA is between 1 to 4
    I want to optimize the same for performance, coz 4 months back, i had about 100+ visitors real time on my website with a traffic of 15000+ per day and now i just have about 30 - 40 visitors and also the website goes down at times for some time and i have to restart mysql.

    I have multiple Databases and making use of max myisam and min of innodb tables



    Any help would be appreciated please


    My server config as below
    HP DL 120 G7, Single Proc Quad Core
    - Intel Xeon E1220 (1 CPU x 4 Cores)
    - 500 GB x 2 SATA Hard Disks on Raid 1
    - 16 GB DDRII ECC Registered RAM

    my.cnf as below
    Code:
    [mysqld]
    
    local-infile=0
    skip-name-resolve
    max_connections=600
    low_priority_updates=1
    myisam-recover=backup,force
    thread_concurrency=8
    concurrent_insert=2
    thread_cache_size=48
    max_allowed_packet=8M
    
    innodb_buffer_pool_size=512M
    innodb_additional_mem_pool_size=10M
    innodb_flush_method=O_DIRECT
    
    symbolic-links=0
    socket=/var/lib/mysql/mysql.sock
    
    interactive_timeout = 100
    connect_timeout = 60
    wait_timeout = 120
    
    tmp_table_size = 256M
    max_heap_table_size = 256M
    join_buffer_size=2M
    read_buffer_size=4M
    sort_buffer_size=2M
    table_open_cache=1024
    read_rnd_buffer_size=2M
    key_buffer =2G
    max_allowed_packet=8M
    max_connect_errors=10
    myisam_sort_buffer_size=64M
    query_cache_limit=3M
    query_cache_size=1G
    query_cache_type=1
    
    open_files_limit=4466
    [mysqldump]
    quick
    max_allowed_packet=16M
    
    [mysql]
    no-auto-rehash
    
    [isamchk]
    key_buffer=128M
    sort_buffer=128M
    read_buffer=4M
    write_buffer=2M
    
    [myisamchk]
    key_buffer_size = 128M
    sort_buffer_size = 128M
    read_buffer = 4M
    write_buffer = 2M
    =================
    mysqlunner resutls
    Code:
    -----------------
    
    -------- General Statistics -----------------------------------------                           ---------
    [--] Skipped version check for MySQLTuner script
    [OK] Currently running supported MySQL version 5.1.70-cll
    [OK] Operating on 64-bit architecture
    
    -------- Storage Engine Statistics ----------------------------------                           ---------
    [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
    [--] Data in MyISAM tables: 2G (Tables: 676)
    [--] Data in InnoDB tables: 137M (Tables: 85)
    [!!] Total fragmented tables: 98
    
    -------- Security Recommendations  ----------------------------------                           ---------
    [OK] All database users have passwords assigned
    
    -------- Performance Metrics ----------------------------------------                           ---------
    [--] Up for: 6h 16m 36s (5M q [246.189 qps], 28K conn, TX: 8B, RX: 1B                           )
    [--] Reads / Writes: 83% / 17%
    [--] Total buffers: 3.8G global + 10.2M per thread (600 max threads)
    [OK] Maximum possible memory usage: 9.8G (62% of installed RAM)
    [OK] Slow queries: 0% (60/5M)
    [OK] Highest usage of available connections: 5% (35/600)
    [OK] Key buffer size / total MyISAM indexes: 2.0G/1.1G
    [OK] Key buffer hit rate: 100.0% (749M cached / 39K reads)
    [OK] Query cache efficiency: 84.1% (4M cached / 5M selects)
    [OK] Query cache prunes per day: 0
    [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 79K sorts)
    [!!] Joins performed without indexes: 455
    [!!] Temporary tables created on disk: 29% (29K on disk / 100K total)
    [OK] Thread cache hit rate: 99% (35 created / 28K connections)
    [OK] Table cache hit rate: 98% (460 open / 467 opened)
    [OK] Open file limit used: 13% (610/4K)
    [OK] Table locks acquired immediately: 99% (1M immediate / 1M locks)
    [OK] InnoDB data size / buffer pool: 137.7M/512.0M
    
    -------- Recommendations --------------------------------------------                           ---------
    General recommendations:
        Run OPTIMIZE TABLE to defragment tables for better performance
        MySQL started within last 24 hours - recommendations may be inacc                           urate
        Enable the slow query log to troubleshoot bad queries
        Adjust your join queries to always utilize indexes
        Temporary table size is already large - reduce result set size
        Reduce your SELECT DISTINCT queries without LIMIT clauses
    Variables to adjust:
        join_buffer_size (> 2.0M, or always use indexes with joins)
    
    
    ==================
    
    tuning-primer.sh results as below
    -------------------------------
    
    SLOW QUERIES
    The slow query log is NOT enabled.
    Current long_query_time = 10.000000 sec.
    You have 60 out of 5611712 that take longer than 10.000000 sec. to complete
    Your long_query_time seems to be fine
    
    BINARY UPDATE LOG
    The binary update log is NOT enabled.
    You will not be able to do point in time recovery
    See [url=http://dev.mysql.com/doc/refman/5.1/en/point-in-time-recovery.html]MySQL :: MySQL 5.1 Reference Manual :: 7.5 Point-in-Time (Incremental) Recovery Using the Binary Log[/url]
    
    WORKER THREADS
    Current thread_cache_size = 48
    Current threads_cached = 30
    Current threads_per_sec = 0
    Historic threads_per_sec = 0
    Your thread_cache_size is fine
    
    MAX CONNECTIONS
    Current max_connections = 600
    Current threads_connected = 4
    Historic max_used_connections = 35
    The number of used connections is 5% of the configured maximum.
    You are using less than 10% of your configured max_connections.
    Lowering max_connections could help to avoid an over-allocation of memory
    See "MEMORY USAGE" section to make sure you are not over-allocating
    
    INNODB STATUS
    Current InnoDB index space = 22 M
    Current InnoDB data space = 137 M
    Current InnoDB buffer pool free = 92 %
    Current innodb_buffer_pool_size = 512 M
    Depending on how much space your innodb indexes take up it may be safe
    to increase this value to up to 2 / 3 of total system memory
    
    MEMORY USAGE
    Max Memory Ever Allocated : 3.86 G
    Configured Max Per-thread Buffers : 6.00 G
    Configured Max Global Buffers : 3.51 G
    Configured Max Memory Limit : 9.51 G
    Physical Memory : 15.64 G
    Max memory limit seem to be within acceptable norms
    
    KEY BUFFER
    Current MyISAM index space = 1.12 G
    Current key_buffer_size = 2.00 G
    Key cache miss rate is 1 : 18978
    Key buffer free ratio = 79 %
    Your key_buffer_size seems to be too high.
    Perhaps you can use these resources elsewhere
    
    QUERY CACHE
    Query cache is enabled
    Current query_cache_size = 1.00 G
    Current query_cache_used = 606 M
    Current query_cache_limit = 3 M
    Current Query cache Memory fill ratio = 59.25 %
    Current query_cache_min_res_unit = 4 K
    MySQL won't cache query results that are larger than query_cache_limit in size
    
    SORT OPERATIONS
    Current sort_buffer_size = 2 M
    Current read_rnd_buffer_size = 2 M
    Sort buffer seems to be fine
    
    JOINS
    Current join_buffer_size = 2.00 M
    You have had 76 queries where a join could not use an index properly
    You have had 379 joins without keys that check for key usage after each row
    You should enable "log-queries-not-using-indexes"
    Then look for non indexed joins in the slow query log.
    If you are unable to optimize your queries you may want to increase your
    join_buffer_size to accommodate larger joins in one pass.
    
    Note! This script will still suggest raising the join_buffer_size when
    ANY joins not using indexes are found.
    
    OPEN FILES LIMIT
    Current open_files_limit = 4466 files
    The open_files_limit should typically be set to at least 2x-3x
    that of table_cache if you have heavy MyISAM usage.
    Your open_files_limit value seems to be fine
    
    TABLE CACHE
    Current table_open_cache = 1024 tables
    Current table_definition_cache = 256 tables
    You have a total of 784 tables
    You have 1024 open tables.
    Current table_cache hit rate is 95%
    , while 100% of your table cache is in use
    You should probably increase your table_cache
    You should probably increase your table_definition_cache value.
    
    TEMP TABLES
    Current max_heap_table_size = 256 M
    Current tmp_table_size = 256 M
    Of 71818 temp tables, 29% were created on disk
    Perhaps you should increase your tmp_table_size and/or max_heap_table_size
    to reduce the number of disk-based temporary tables
    Note! BLOB and TEXT columns are not allow in memory tables.
    If you are using these columns raising these values might not impact your
    ratio of on disk temp tables.
    
    TABLE SCANS
    Current read_buffer_size = 4 M
    Current table scan ratio = 448 : 1
    read_buffer_size seems to be fine
    
    TABLE LOCKING
    Current Lock Wait ratio = 1 : 2558
    You may benefit from selective use of InnoDB.
    
    ======================
     
  2. thinkbot

    thinkbot Well-Known Member

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    adjust:

    tmp_table_size = 50M
    max_heap_table_size = 50M
    join_buffer_size=1M
    read_buffer_size=128K
    sort_buffer_size=2M
    read_rnd_buffer_size=256K
    table_open_cache=1024

    query_cache_size=100M
    myisam_sort_buffer_size=512M


    slow_query_log=1
    slow_query_log_file=mysql-slow.log
    long_query_time=0.1


    - what script do you use ? custom or CMS ? with some third party plugins ?
    - it would be good to review your slow queries, since
    [!!] Temporary tables created on disk: 29% (29K on disk / 100K total)
     
  3. harivaag

    harivaag Registered

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    HI,

    Thanks, have applied the same and will check for the day today...

    - - - Updated - - -

    hi sorry forgot to answer your questions,
    we use X-cart for the website and use custom build php based CMS
     
  4. harivaag

    harivaag Registered

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    Hi,

    After making the changes and checking for a day, just now the LA just went up to 80% and then i had to restart....
    Kindly help me to resolve the same
     
  5. thinkbot

    thinkbot Well-Known Member

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    what do you mean by LA and where do you check it ?

    please review slow queries, like that :

    cd /root/install
    wget http://percona.com/get/pt-query-digest
    chmod +x pt-query-digest
    ./pt-query-digest /var/lib/mysql/mysql-slow.log > slow.txt

    and copy slow.txt here
     
  6. harivaag

    harivaag Registered

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    Thanks,

    LA means Load Average on the PUTTY

    I will put the slow.txt soon
     
  7. cPanelMichael

    cPanelMichael Forums Analyst
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