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mysql using about 80% cpu, recomendation?

Discussion in 'Workarounds and Optimization' started by fastuning, Feb 18, 2018.

  1. fastuning

    fastuning Registered

    Jun 10, 2014
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    my mysql is using about 70-80% every time of cpu and about 5% memory, and many times when high traffic, websites takes too long to load

    could someone help me?

    my server is 8 core with 32gb ram, im using cloudlinux

    here is my my.cnf and mysqltuner log

    tmpdir =/dev/shm
    max_connections = 1024
    key_buffer_size = 1024M
    myisam_sort_buffer_size = 64M
    join_buffer_size = 1M
    read_buffer_size = 1M
    sort_buffer_size = 256K
    thread_cache_size = 384
    wait_timeout = 20
    connect_timeout = 10
    tmp_table_size = 64M
    max_heap_table_size = 64M
    max_allowed_packet = 64M
    net_buffer_length = 16384
    max_connect_errors = 10
    thread_concurrency = 16
    concurrent_insert = 2
    read_rnd_buffer_size = 786432
    bulk_insert_buffer_size = 8M
    query_cache_limit = 7M
    query_cache_size = 64M
    query_cache_type = 1
    query_prealloc_size = 262144
    query_alloc_block_size = 65536
    transaction_alloc_block_size = 8192
    transaction_prealloc_size = 4096
    max_write_lock_count = 16
    innodb_buffer_pool_size=8G   #75 % of RAM
    innodb_thread_concurrency=8   # of cpus
    open_files_limit = 8192
    max_allowed_packet = 16M
    key_buffer = 384M
    sort_buffer = 384M
    read_buffer = 256M
    -------- Performance Metrics -----------------------------------------------------------------------
    [--] Up for: 2d 3h 25m 54s (23M q [127.290 qps], 468K conn, TX: 138G, RX: 7G)
    [--] Reads / Writes: 89% / 11%
    [--] Binary logging is disabled
    [--] Physical Memory     : 31.3G
    [--] Max MySQL memory    : 12.9G
    [--] Other process memory: 3.9G
    [--] Total buffers: 9.1G global + 3.2M per thread (1024 max threads)
    [--] P_S Max memory usage: 555M
    [--] Galera GCache Max memory usage: 0B
    [OK] Maximum reached memory usage: 10.0G (31.77% of installed RAM)
    [OK] Maximum possible memory usage: 12.9G (41.28% of installed RAM)
    [OK] Overall possible memory usage with other process is compatible with memory available
    [OK] Slow queries: 0% (5K/23M)
    [OK] Highest usage of available connections: 8% (85/1024)
    [OK] Aborted connections: 0.55%  (2598/468725)
    [!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
    [!!] Query cache may be disabled by default due to mutex contention.
    [OK] Query cache efficiency: 61.7% (12M cached / 19M selects)
    [!!] Query cache prunes per day: 1008253
    [OK] Sorts requiring temporary tables: 0% (2K temp sorts / 34M sorts)
    [!!] Joins performed without indexes: 150075
    [!!] Temporary tables created on disk: 52% (577K on disk / 1M total)
    [OK] Thread cache hit rate: 99% (85 created / 468K connections)
    [!!] Table cache hit rate: 1% (2K open / 102K opened)
    [OK] Open file limit used: 24% (1K/8K)
    [OK] Table locks acquired immediately: 99% (38M immediate / 38M locks)
    -------- Performance schema ------------------------------------------------------------------------
    [--] Memory used by P_S: 555.4M
    [--] Sys schema isn't installed.
    -------- ThreadPool Metrics ------------------------------------------------------------------------
    [--] ThreadPool stat is disabled.
    -------- MyISAM Metrics ----------------------------------------------------------------------------
    [!!] Key buffer used: 26.8% (287M used / 1B cache)
    [OK] Key buffer size / total MyISAM indexes: 1.0G/1.5G
    [OK] Read Key buffer hit rate: 100.0% (2B cached / 572K reads)
    [!!] Write Key buffer hit rate: 30.1% (2M cached / 899K writes)
    -------- InnoDB Metrics ----------------------------------------------------------------------------
    [--] InnoDB is enabled.
    [--] InnoDB Thread Concurrency: 8
    [OK] InnoDB File per table is activated
    [OK] InnoDB buffer pool / data size: 8.0G/1.2G
    [!!] Ratio InnoDB log file size / InnoDB Buffer pool size (1.171875 %): 48.0M * 2/8.0G should be equal 25%
    [OK] InnoDB buffer pool instances: 8
    [--] InnoDB Buffer Pool Chunk Size not used or defined in your version
    [OK] InnoDB Read buffer efficiency: 100.00% (786635092 hits/ 786673138 total)
    [!!] InnoDB Write Log efficiency: 51.42% (236640 hits/ 460226 total)
    [OK] InnoDB log waits: 0.00% (0 waits / 223586 writes)
    -------- AriaDB Metrics ----------------------------------------------------------------------------
    [--] AriaDB is disabled.
    -------- TokuDB Metrics ----------------------------------------------------------------------------
    [--] TokuDB is disabled.
    -------- XtraDB Metrics ----------------------------------------------------------------------------
    [--] XtraDB is disabled.
    -------- RocksDB Metrics ---------------------------------------------------------------------------
    [--] RocksDB is disabled.
    -------- Spider Metrics ----------------------------------------------------------------------------
    [--] Spider is disabled.
    -------- Connect Metrics ---------------------------------------------------------------------------
    [--] Connect is disabled.
    -------- Galera Metrics ----------------------------------------------------------------------------
    [--] Galera is disabled.
    -------- Replication Metrics -----------------------------------------------------------------------
    [--] Galera Synchronous replication: NO
    [--] No replication slave(s) for this server.
    [--] This is a standalone server.
    -------- Recommendations ---------------------------------------------------------------------------
    General recommendations:
        /var/lib/mysql/ is > 32Mb, you should analyze why or implement a rotation log strategy such as logrotate!
        Control warning line(s) into /var/lib/mysql/ file
        Control error line(s) into /var/lib/mysql/ file
        Run OPTIMIZE TABLE to defragment tables for better performance
          OPTIMIZE TABLE `modsec`.`hits`; -- can free 382.777297973633 MB
        Total freed space after theses OPTIMIZE TABLE : 382.777297973633 Mb
        Set up a Secure Password for user@host ( SET PASSWORD FOR 'user'@'SpecificDNSorIp' = PASSWORD('secure_password'); )
        Restrict Host for user@% to user@SpecificDNSorIp
        Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
        Adjust your join queries to always utilize indexes
        When making adjustments, make tmp_table_size/max_heap_table_size equal
        Reduce your SELECT DISTINCT queries which have no LIMIT clause
        Increase table_open_cache gradually to avoid file descriptor limits
        Read this before increasing table_open_cache over 64: table_cache negative scalability
        Beware that open_files_limit (8192) variable
        should be greater than table_open_cache (2000)
        Consider installing Sys schema from GitHub - mysql/mysql-sys: The MySQL sys schema
        Read this before changing innodb_log_file_size and/or innodb_log_files_in_group: MySQL :: MySQL 5.7 Reference Manual :: 14.7.2 Changing the Number or Size of InnoDB Redo Log Files
    Variables to adjust:
        query_cache_size (=0)
        query_cache_type (=0)
        query_cache_size (> 64M)
        join_buffer_size (> 1.0M, or always use indexes with joins)
        tmp_table_size (> 64M)
        max_heap_table_size (> 64M)
        table_open_cache (> 2000)
        innodb_log_file_size should be (=1G) if possible, so InnoDB total log files size equals to 25% of buffer pool size.
    #1 fastuning, Feb 18, 2018
    Last edited by a moderator: Feb 19, 2018
  2. cPanelMichael

    cPanelMichael Forums Analyst
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    Apr 11, 2011
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    Advice about tuning specific configuration values typically requires the help of a qualified system administrator. I'll leave this thread open for additional user-feedback, but I did want to note the "mysqladmin processlist" command is helpful if you are noticing bad MySQL performance. The command can help determine if any specific databases are responsible for the poor performance.

    You can also find a list of companies offering system administration services if you do not receive sufficient user-feedback to this thread:

    System Administration Services | cPanel Forums

    Thank you.
    cesarlopes likes this.
  3. fastuning

    fastuning Registered

    Jun 10, 2014
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    Yes the problem is after a sysadmin check all parameters and all is ok, all seems similar, and the problem begin after migration from EA3 to EA4, same mysql configuration and now mysql pass from 20-25% to 80-90%

    i have open a ticket, because must be something wrong in the migration

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