Mysql高CPU使用率(100%)

时间:2015-05-27 13:33:46

标签: php mysql mysqli

我们正面临着mysql进程的高CPU使用率问题(差不多100%)。 以下是与服务器相关的信息

  1. 服务器信息:Windows Server 2008 R2 Datacenter Edition Service Pack 1 i586
  2. 运行PHP:Microsoft-IIS / 7.5
  3. PHP版本:5.3.28
  4. MySql Server版本:5.5.16 - MySQL社区服务器(GPL)
  5. 我们还添加了my.ini文件的代码 - mysql的配置文件

        # MySQL Server Instance Configuration File
    # ----------------------------------------------------------------------
    # Generated by the MySQL Server Instance Configuration Wizard
    #
    #
    # Installation Instructions
    # ----------------------------------------------------------------------
    #
    # On Linux you can copy this file to /etc/my.cnf to set global options,
    # mysql-data-dir/my.cnf to set server-specific options
    # (@localstatedir@ for this installation) or to
    # ~/.my.cnf to set user-specific options.
    #
    # On Windows you should keep this file in the installation directory 
    # of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
    # make sure the server reads the config file use the startup option 
    # "--defaults-file". 
    #
    # To run run the server from the command line, execute this in a 
    # command line shell, e.g.
    # mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
    #
    # To install the server as a Windows service manually, execute this in a 
    # command line shell, e.g.
    # mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
    #
    # And then execute this in a command line shell to start the server, e.g.
    # net start MySQLXY
    #
    #
    # Guildlines for editing this file
    # ----------------------------------------------------------------------
    #
    # In this file, you can use all long options that the program supports.
    # If you want to know the options a program supports, start the program
    # with the "--help" option.
    #
    # More detailed information about the individual options can also be
    # found in the manual.
    #
    #
    # CLIENT SECTION
    # ----------------------------------------------------------------------
    #
    # The following options will be read by MySQL client applications.
    # Note that only client applications shipped by MySQL are guaranteed
    # to read this section. If you want your own MySQL client program to
    # honor these values, you need to specify it as an option during the
    # MySQL client library initialization.
    #
    [client]
    
    port=3306
    
    [mysql]
    
    default-character-set=utf8
    
    
    # SERVER SECTION
    # ----------------------------------------------------------------------
    #
    # The following options will be read by the MySQL Server. Make sure that
    # you have installed the server correctly (see above) so it reads this 
    # file.
    #
    [mysqld]
    
    # The TCP/IP Port the MySQL Server will listen on
    port=3306
    
    
    #Path to installation directory. All paths are usually resolved relative to this.
    basedir="C:/Program Files/MySQL/MySQL Server 5.5/"
    
    #Path to the database root
    datadir="C:/ProgramData/MySQL/MySQL Server 5.5/Data/"
    
    # The default character set that will be used when a new schema or table is
    # created and no character set is defined
    character-set-server=utf8
    
    # The default storage engine that will be used when create new tables when
    default-storage-engine=INNODB
    
    # Set the SQL mode to strict
    sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
    
    # The maximum amount of concurrent sessions the MySQL server will
    # allow. One of these connections will be reserved for a user with
    # SUPER privileges to allow the administrator to login even if the
    # connection limit has been reached.
    max_connections=100
    
    # Query cache is used to cache SELECT results and later return them
    # without actual executing the same query once again. Having the query
    # cache enabled may result in significant speed improvements, if your
    # have a lot of identical queries and rarely changing tables. See the
    # "Qcache_lowmem_prunes" status variable to check if the current value
    # is high enough for your load.
    # Note: In case your tables change very often or if your queries are
    # textually different every time, the query cache may result in a
    # slowdown instead of a performance improvement.
    query_cache_size=0
    
    # The number of open tables for all threads. Increasing this value
    # increases the number of file descriptors that mysqld requires.
    # Therefore you have to make sure to set the amount of open files
    # allowed to at least 4096 in the variable "open-files-limit" in
    # section [mysqld_safe]
    table_cache=256
    
    # Maximum size for internal (in-memory) temporary tables. If a table
    # grows larger than this value, it is automatically converted to disk
    # based table This limitation is for a single table. There can be many
    # of them.
    tmp_table_size=205M
    
    
    # How many threads we should keep in a cache for reuse. When a client
    # disconnects, the client's threads are put in the cache if there aren't
    # more than thread_cache_size threads from before.  This greatly reduces
    # the amount of thread creations needed if you have a lot of new
    # connections. (Normally this doesn't give a notable performance
    # improvement if you have a good thread implementation.)
    thread_cache_size=8
    
    #*** MyISAM Specific options
    
    # The maximum size of the temporary file MySQL is allowed to use while
    # recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
    # If the file-size would be bigger than this, the index will be created
    # through the key cache (which is slower).
    myisam_max_sort_file_size=100G
    
    # If the temporary file used for fast index creation would be bigger
    # than using the key cache by the amount specified here, then prefer the
    # key cache method.  This is mainly used to force long character keys in
    # large tables to use the slower key cache method to create the index.
    myisam_sort_buffer_size=410M
    
    # Size of the Key Buffer, used to cache index blocks for MyISAM tables.
    # Do not set it larger than 30% of your available memory, as some memory
    # is also required by the OS to cache rows. Even if you're not using
    # MyISAM tables, you should still set it to 8-64M as it will also be
    # used for internal temporary disk tables.
    key_buffer_size=354M
    
    # Size of the buffer used for doing full table scans of MyISAM tables.
    # Allocated per thread, if a full scan is needed.
    read_buffer_size=64K
    read_rnd_buffer_size=256K
    
    # This buffer is allocated when MySQL needs to rebuild the index in
    # REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
    # into an empty table. It is allocated per thread so be careful with
    # large settings.
    sort_buffer_size=256K
    
    
    #*** INNODB Specific options ***
    
    
    # Use this option if you have a MySQL server with InnoDB support enabled
    # but you do not plan to use it. This will save memory and disk space
    # and speed up some things.
    #skip-innodb
    
    # Additional memory pool that is used by InnoDB to store metadata
    # information.  If InnoDB requires more memory for this purpose it will
    # start to allocate it from the OS.  As this is fast enough on most
    # recent operating systems, you normally do not need to change this
    # value. SHOW INNODB STATUS will display the current amount used.
    innodb_additional_mem_pool_size=15M
    
    # If set to 1, InnoDB will flush (fsync) the transaction logs to the
    # disk at each commit, which offers full ACID behavior. If you are
    # willing to compromise this safety, and you are running small
    # transactions, you may set this to 0 or 2 to reduce disk I/O to the
    # logs. Value 0 means that the log is only written to the log file and
    # the log file flushed to disk approximately once per second. Value 2
    # means the log is written to the log file at each commit, but the log
    # file is only flushed to disk approximately once per second.
    innodb_flush_log_at_trx_commit=1
    
    # The size of the buffer InnoDB uses for buffering log data. As soon as
    # it is full, InnoDB will have to flush it to disk. As it is flushed
    # once per second anyway, it does not make sense to have it very large
    # (even with long transactions).
    innodb_log_buffer_size=7M
    
    # InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
    # row data. The bigger you set this the less disk I/O is needed to
    # access data in tables. On a dedicated database server you may set this
    # parameter up to 80% of the machine physical memory size. Do not set it
    # too large, though, because competition of the physical memory may
    # cause paging in the operating system.  Note that on 32bit systems you
    # might be limited to 2-3.5G of user level memory per process, so do not
    # set it too high.
    innodb_buffer_pool_size=686M
    
    # Size of each log file in a log group. You should set the combined size
    # of log files to about 25%-100% of your buffer pool size to avoid
    # unneeded buffer pool flush activity on log file overwrite. However,
    # note that a larger logfile size will increase the time needed for the
    # recovery process.
    innodb_log_file_size=100M
    
    # Number of threads allowed inside the InnoDB kernel. The optimal value
    # depends highly on the application, hardware as well as the OS
    # scheduler properties. A too high value may lead to thread thrashing.
    innodb_thread_concurrency=8
    

    这是我们在脚本中用来连接mysql的代码:

    public function MySqlConnect()
    {
        static $MySqli;
    
        if (!isset($MySqli))
        {
            $MySqli = @new mysqli($this->DbHost, $this->DbUser, $this->Dbpassword, $this->Db);
        }
        return $MySqli;
    }
    

    请帮助我们了解my.ini文件或连接脚本有什么问题导致mysql 100%的CPU使用率,或者我们需要更改一些不同的内容。

    感谢。

1 个答案:

答案 0 :(得分:3)

MySQL高CPU与PHP无关。您首先需要了解高CPU的原因然后再进行处理。执行以下操作以跟踪实际原因

  1. 启用 slow_query.log ,查找非常适合优化的查询。 slow_query.log中的一些查询可能会使用大量的CPU

  2. 如果您有任何线索,请检查这些状态

    SHOW ENGINE INNODB STATUS\G; SHOW FULL PROCESSLIST;

  3. 确保所有表格拆分

  4. 增加innodb_buffer_pool_size以便有更多缓存

  5. 还调整以下参数。如果可能的话,使用 mysqltuner.pl 来获取建议值以在MySQL配置中调整这些参数

    innodb_fast_shutdown=0 innodb_log_buffer_size innodb_log_file_size innodb_flush_method=O_DIRECT query_cache_size=0