mysql性能優化

時間 2019-11-13

標籤 mysql 性能優化欄目 MySQL 简体版

原文原文鏈接

標題：MySQL-5.5.32 配置文件優化詳解做者：陳明乾 的BLOG 轉載地址：http://freeloda.blog.51cto.com/2033581/1253709 html

大綱mysql

1、配置文件說明web

my-small.cnf sql

my-medium.cnf 數據庫

my-large.cnf vim

my-huge.cnf windows

my-innodb-heavy-4G.cnf promise

2、詳解 my-innodb-heavy-4G.cnf緩存

3、配置文件優化安全

注：環境說明，CentO5.5 x86_64+MySQL-5.5.32 相關軟件下載：http://yunpan.cn/QtaCuLHLRKzRq

1、配置文件說明

Mysql-5.5.32是Mysql5.5系列中最後一個版本，也是最後一個有配置文件的版本，爲何這麼說呢，用過5.6的博友都知道，在mysql5.6中已經不提供配置文件選擇，只有一個默認的配置文件，好了，咱們今天說的是5.5.32這個版，就不和你們說5.6了，下面咱們來具體說一下，mysql5.5.32中，提供可選的幾個配置文件，

my-small.cnf

my-medium.cnf

my-large.cnf

my-huge.cnf

my-innodb-heavy-4G.cnf

下面咱們就來分別的看一下^_^……

1.my-small.cnf

 
        [root@mysql support-files] 
        # vim my-small.cnf 
       
        # Example MySQL config file for small systems. 
       
        # This is for a system with little memory (<= 64M) where MySQL is only used  
       
        # from time to time and it's important that the mysqld daemon   
       
        # doesn't use much resources.

這是my-small.cnf配置文件中開頭的簡介，它說明了，這個配置文件是在內存小於等於64M時使用的，小型數據庫系統，目的是不佔更多的系統資源！

2.my-medium.cnf

 
        [root@mysql support-files] 
        # vim my-medium.cnf 
       
        # Example MySQL config file for medium systems. 
       
        # This is for a system with little memory (32M - 64M) where MySQL plays  
       
        # an important part, or systems up to 128M where MySQL is used together with   
       
        # other programs (such as a web server)

這個配置文件是中型數據系統使用，內存在128M左右！

3.my-large.cnf

 
        [root@mysql support-files] 
        # vim my-large.cnf 
       
        # Example MySQL config file for large systems.  
       
        # This is for a large system with memory = 512M where the system runs mainly   
       
        # MySQL.

這個配置文件是大型數據庫系統使用，內存在512M左右！

4.my-huge.cnf

 
        [root@mysql support-files] 
        # vim my-huge.cnf 
       
        # Example MySQL config file for very large systems.  
       
        # This is for a large system with memory of 1G-2G where the system runs mainly   
       
        # MySQL.

這個配置文件是巨型數據庫系統使用，內存在1G-2G左右！

5.my-innodb-heavy-4G.cnf

 
        [root@mysql support-files] 
        # vim my-innodb-heavy-4G.cnf 
       
        #BEGIN CONFIG INFO  
       
        #DESCR: 4GB RAM, InnoDB only, ACID, few connections, heavy queries   
       
        #TYPE: SYSTEM   
       
        #END CONFIG INFO 
       
        # This is a MySQL example config file for systems with 4GB of memory  
       
        # running mostly MySQL using InnoDB only tables and performing complex   
       
        # queries with few connections.

這個配置文件主要做用是,支持4G內存，支持InnoDB引擎，支持事務（ACID）等特性所使用！

說明：ACID，指數據庫事務正確執行的四個基本要素的縮寫。包含：原子性(Atomicity）、一致性（Consistency）、隔離性（Isolation）、持久性（Durability）！

6.總結

從上面的說明咱們能夠出，基本是經過內存大小來選擇mysql的配置文件的，那有博友會說了，如今的服務器動不動就是32G內存或者64G內存，甚至更大的內存，你那個配置文件最大隻支持4G內存是否是有點小了，確認會有這樣的問題，從mysql5.6之後，爲了更大的發揮mysql的性能，已經去除了配置文件選擇，只有一個默認的配置文件，裏面只有一些基本配置，全部設置管理員均可以根據本身實際的需求進行自行設置，好了說了這麼多，咱們就來講一說，在企業的用的最多的my-innodb-heavy-4G.cnf配置文件！

2、詳解 my-innodb-heavy-4G.cnf

1.詳細說明

注：下面是my-innodb-heavy-4G.cnf默認配置我沒有作任何修改，下面咱們就來詳細的說一說！

 
        [root@mysql support-files] 
        # vim my-innodb-heavy-4G.cnf 
       
        #BEGIN CONFIG INFO  
       
        #DESCR: 4GB RAM, InnoDB only, ACID, few connections, heavy queries   
       
        #TYPE: SYSTEM   
       
        #END CONFIG INFO 
       
        #  
       
        # This is a MySQL example config file for systems with 4GB of memory   
       
        # running mostly MySQL using InnoDB only tables and performing complex   
       
        # queries with few connections.   
       
        #   
       
        # MySQL programs look for option files in a set of   
       
        # locations which depend on the deployment platform.   
       
        # You can copy this option file to one of those   
       
        # locations. For information about these locations, see:   
       
        # http://dev.mysql.com/doc/mysql/en/option-files.html 
       
        #   
       
        # In this file, you can use all long options that a program supports.   
       
        # If you want to know which options a program supports, run the program   
       
        # with the "--help" option.   
       
        #   
       
        # More detailed information about the individual options can also be   
       
        # found in the manual.   
       
        # 
       
        #  
       
        # 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.   
       
        # 
       
        # 如下選項會被MySQL客戶端應用讀取, 注意只有MySQL附帶的客戶端應用程序保證能夠讀取這段內容,若是你想你本身的MySQL應用程序獲取這些值,須要在MySQL客戶端庫初始化的時候指定這些選項 
       
        [client]  
       
        #password    = [your_password] #mysql客戶端鏈接mysql時的密碼   
       
        port        = 3306  
        #mysql客戶端鏈接時的默認端口   
       
        socket        =  
        /tmp/mysql 
        .sock  
        #與mysql服務器本地通訊所使用的socket文件路徑 
       
        # *** Application-specific options follow here *** 
       
        #  
       
        # The MySQL server   
       
        #   
       
        [mysqld] 
       
        # generic configuration options #通常配置選項  
       
        port        = 3306  
        #mysql服務器監聽的默認端口   
       
        socket        =  
        /tmp/mysql 
        .sock  
        #socket本地通訊文件路徑 
       
        # back_log is the number of connections the operating system can keep in  
       
        # the listen queue, before the MySQL connection manager thread has   
       
        # processed them. If you have a very high connection rate and experience   
       
        # "connection refused" errors, you might need to increase this value.   
       
        # Check your OS documentation for the maximum value of this parameter.   
       
        # Attempting to set back_log higher than your operating system limit   
       
        # will have no effect. 
       
        # back_log 是操做系統在監聽隊列中所能保持的鏈接數,  
       
        # 隊列保存了在MySQL鏈接管理器線程處理以前的鏈接.   
       
        # 若是你有很是高的鏈接率而且出現「connection refused」報錯,   
       
        # 你就應該增長此處的值.   
       
        # 檢查你的操做系統能打開文件數來獲取這個變量的最大值.   
       
        # 若是將back_log設定到比你操做系統限制更高的值,將會沒有效果 
       
        back_log = 50 
       
        # Don't listen on a TCP/IP port at all. This can be a security  
       
        # enhancement, if all processes that need to connect to mysqld run   
       
        # on the same host.  All interaction with mysqld must be made via Unix   
       
        # sockets or named pipes.   
       
        # Note that using this option without enabling named pipes on Windows   
       
        # (via the "enable-named-pipe" option) will render mysqld useless! 
       
        # 不在TCP/IP端口上進行監聽.  
       
        # 若是全部的進程都是在同一臺服務器鏈接到本地的mysqld,   
       
        # 這樣設置將是加強安全的方法   
       
        # 全部mysqld的鏈接都是經過Unix sockets 或者命名管道進行的.   
       
        # 注意在windows下若是沒有打開命名管道選項而只是用此項   
       
        # (經過 「enable-named-pipe」 選項) 將會致使mysql服務沒有任何做用! 
       
        #skip-networking #默認是沒有開啓的 
       
        # 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. 
       
        # MySQL 服務器所容許的同時會話數的上限  
       
        # 其中一個鏈接將被SUPER權限保留做爲管理員登陸.   
       
        # 即使已經達到了鏈接數的上限.   
       
        max_connections = 100 
       
        # Maximum amount of errors allowed per host. If this limit is reached,  
       
        # the host will be blocked from connecting to the MySQL server until   
       
        # "FLUSH HOSTS" has been run or the server was restarted. Invalid   
       
        # passwords and other errors during the connect phase result in   
       
        # increasing this value. See the "Aborted_connects" status variable for   
       
        # global counter. 
       
        # 每一個客戶端鏈接最大的錯誤容許數量,若是達到了此限制.  
       
        # 這個客戶端將會被MySQL服務阻止直到執行了」FLUSH HOSTS」 或者服務重啓   
       
        # 非法的密碼以及其餘在連接時的錯誤會增長此值.   
       
        # 查看 「Aborted_connects」 狀態來獲取全局計數器.   
       
        max_connect_errors = 10 
       
        # 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] 
       
        # 全部線程所打開表的數量.  
       
        # 增長此值就增長了mysqld所須要的文件描述符的數量   
       
        # 這樣你須要確認在[mysqld_safe]中 「open-files-limit」 變量設置打開文件數量容許至少2048 
       
        table_open_cache = 2048 
       
        # Enable external file level locking. Enabled file locking will have a  
       
        # negative impact on performance, so only use it in case you have   
       
        # multiple database instances running on the same files (note some   
       
        # restrictions still apply!) or if you use other software relying on   
       
        # locking MyISAM tables on file level. 
       
        # 容許外部文件級別的鎖. 打開文件鎖會對性能形成負面影響  
       
        # 因此只有在你在一樣的文件上運行多個數據庫實例時才使用此選項(注意仍會有其餘約束!)   
       
        # 或者你在文件層面上使用了其餘一些軟件依賴來鎖定MyISAM表 
       
        #external-locking #默認是沒有開啓的 
       
        # The maximum size of a query packet the server can handle as well as  
       
        # maximum query size server can process (Important when working with   
       
        # large BLOBs).  enlarged dynamically, for each connection. 
       
        # 服務所能處理的請求包的最大大小以及服務所能處理的最大的請求大小(當與大的BLOB字段一塊兒工做時至關必要)  
       
        # 每一個鏈接獨立的大小.大小動態增長   
       
        max_allowed_packet = 16M 
       
        # The size of the cache to hold the SQL statements for the binary log  
       
        # during a transaction. If you often use big, multi-statement   
       
        # transactions you can increase this value to get more performance. All   
       
        # statements from transactions are buffered in the binary log cache and   
       
        # are being written to the binary log at once after the COMMIT.  If the   
       
        # transaction is larger than this value, temporary file on disk is used   
       
        # instead.  This buffer is allocated per connection on first update   
       
        # statement in transaction 
       
        # 在一個事務中binlog爲了記錄SQL狀態所持有的cache大小  
       
        # 若是你常用大的,多聲明的事務,你能夠增長此值來獲取更大的性能.   
       
        # 全部從事務來的狀態都將被緩衝在binlog緩衝中而後在提交後一次性寫入到binlog中   
       
        # 若是事務比此值大, 會使用磁盤上的臨時文件來替代.   
       
        # 此緩衝在每一個鏈接的事務第一次更新狀態時被建立   
       
        binlog_cache_size = 1M 
       
        # Maximum allowed size for a single HEAP (in memory) table. This option  
       
        # is a protection against the accidential creation of a very large HEAP   
       
        # table which could otherwise use up all memory resources. 
       
        # 獨立的內存表所容許的最大容量.  
       
        # 此選項爲了防止意外建立一個超大的內存表致使永盡全部的內存資源.   
       
        max_heap_table_size = 64M 
       
        # Size of the buffer used for doing full table scans.  
       
        # Allocated per thread, if a full scan is needed. 
       
        #MySql讀入緩衝區大小。對錶進行順序掃描的請求將分配一個讀入緩衝區，MySql會爲它分#配一段內存緩衝區。read_buffer_size變量控制這一緩衝區的大小。若是對錶的順序掃描請求很是頻繁，#而且你認爲頻繁掃描進行得太慢，能夠經過增長該變量值以及內存緩衝區大小提升其性能。  
       
        read_buffer_size = 2M 
       
        # When reading rows in sorted order after a sort, the rows are read  
       
        # through this buffer to avoid disk seeks. You can improve ORDER BY   
       
        # performance a lot, if set this to a high value.   
       
        # Allocated per thread, when needed. 
       
        #是MySql的隨機讀緩衝區大小。當按任意順序讀取行時(例如，按照排序順序)，將分配一個隨機讀緩存區。進行排序查詢時，MySql會首先掃描一遍該緩衝，以免磁盤搜索，提升查詢速度，若是需#要排序大量數據，可適當調高該值。但MySql會爲每一個客戶鏈接發放該緩衝空間，因此應儘可能適當設置該值，以免內存開銷過大。  
       
        read_rnd_buffer_size = 16M 
       
        # Sort buffer is used to perform sorts for some ORDER BY and GROUP BY  
       
        # queries. If sorted data does not fit into the sort buffer, a disk   
       
        # based merge sort is used instead - See the "Sort_merge_passes"   
       
        # status variable. Allocated per thread if sort is needed. 
       
        # 排序緩衝被用來處理相似ORDER BY以及GROUP BY隊列所引發的排序  
       
        # 若是排序後的數據沒法放入排序緩衝,   
       
        # 一個用來替代的基於磁盤的合併分類會被使用   
       
        # 查看 「Sort_merge_passes」 狀態變量.   
       
        # 在排序發生時由每一個線程分配   
       
        sort_buffer_size = 8M 
       
        # This buffer is used for the optimization of full JOINs (JOINs without  
       
        # indexes). Such JOINs are very bad for performance in most cases   
       
        # anyway, but setting this variable to a large value reduces the   
       
        # performance impact. See the "Select_full_join" status variable for a   
       
        # count of full JOINs. Allocated per thread if full join is found 
       
        # 此緩衝被使用來優化全聯合(full JOINs 不帶索引的聯合).  
       
        # 相似的聯合在極大多數狀況下有很是糟糕的性能表現,   
       
        # 可是將此值設大可以減輕性能影響.   
       
        # 經過 「Select_full_join」 狀態變量查看全聯合的數量   
       
        # 當全聯合發生時,在每一個線程中分配   
       
        join_buffer_size = 8M 
       
        # 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.) 
       
        # 咱們在cache中保留多少線程用於重用  
       
        # 當一個客戶端斷開鏈接後,若是cache中的線程還少於thread_cache_size,   
       
        # 則客戶端線程被放入cache中.   
       
        # 這能夠在你須要大量新鏈接的時候極大的減小線程建立的開銷   
       
        # (通常來講若是你有好的線程模型的話,這不會有明顯的性能提高.)   
       
        thread_cache_size = 8 
       
        # This permits the application to give the threads system a hint for the  
       
        # desired number of threads that should be run at the same time.  This   
       
        # value only makes sense on systems that support the thread_concurrency()   
       
        # function call (Sun Solaris, for example).   
       
        # You should try [number of CPUs]*(2..4) for thread_concurrency 
       
        # 此容許應用程序給予線程系統一個提示在同一時間給予渴望被運行的線程的數量.  
       
        # 此值只對於支持 thread_concurrency() 函數的系統有意義( 例如Sun Solaris).   
       
        # 你可能夠嘗試使用 [CPU數量]*(2..4) 來做爲thread_concurrency的值   
       
        thread_concurrency = 8 
       
        # 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. 
       
        # 查詢緩衝常被用來緩衝 SELECT 的結果而且在下一次一樣查詢的時候再也不執行直接返回結果.  
       
        # 打開查詢緩衝能夠極大的提升服務器速度, 若是你有大量的相同的查詢而且不多修改表.   
       
        # 查看 「Qcache_lowmem_prunes」 狀態變量來檢查是否當前值對於你的負載來講是否足夠高.   
       
        # 注意: 在你表常常變化的狀況下或者若是你的查詢原文每次都不一樣,   
       
        # 查詢緩衝也許引發性能降低而不是性能提高.   
       
        query_cache_size = 64M 
       
        # Only cache result sets that are smaller than this limit. This is to  
       
        # protect the query cache of a very large result set overwriting all   
       
        # other query results. 
       
        # 只有小於此設定值的結果纔會被緩衝  
       
        # 此設置用來保護查詢緩衝,防止一個極大的結果集將其餘全部的查詢結果都覆蓋. 
       
        query_cache_limit = 2M 
       
        # Minimum word length to be indexed by the full text search index.  
       
        # You might wish to decrease it if you need to search for shorter words.   
       
        # Note that you need to rebuild your FULLTEXT index, after you have   
       
        # modified this value. 
       
        # 被全文檢索索引的最小的字長.  
       
        # 你也許但願減小它,若是你須要搜索更短字的時候.   
       
        # 注意在你修改此值以後,   
       
        # 你須要重建你的 FULLTEXT 索引   
       
        ft_min_word_len = 4 
       
        # If your system supports the memlock() function call, you might want to  
       
        # enable this option while running MySQL to keep it locked in memory and   
       
        # to avoid potential swapping out in case of high memory pressure. Good   
       
        # for performance. 
       
        # 若是你的系統支持 memlock() 函數,你也許但願打開此選項用以讓運行中的mysql在在內存高度緊張的時候,數據在內存中保持鎖定而且防止可能被swapping out  
       
        # 此選項對於性能有益   
       
        #memlock 
       
        # Table type which is used by default when creating new tables, if not  
       
        # specified differently during the CREATE TABLE statement. 
       
        # 當建立新表時做爲默認使用的表類型,  
       
        # 若是在建立表示沒有特別執行表類型,將會使用此值   
       
        default-storage-engine = MYISAM 
       
        # Thread stack size to use. This amount of memory is always reserved at  
       
        # connection time. MySQL itself usually needs no more than 64K of   
       
        # memory, while if you use your own stack hungry UDF functions or your   
       
        # OS requires more stack for some operations, you might need to set this   
       
        # to a higher value. 
       
        # 線程使用的堆大小. 此容量的內存在每次鏈接時被預留.  
       
        # MySQL 自己常不會須要超過64K的內存   
       
        # 若是你使用你本身的須要大量堆的UDF函數   
       
        # 或者你的操做系統對於某些操做須要更多的堆,   
       
        # 你也許須要將其設置的更高一點.   
       
        thread_stack = 192K 
       
        # Set the default transaction isolation level. Levels available are: 
       
        # 設定默認的事務隔離級別.可用的級別以下:  
       
        # READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, SERIALIZABLE   
       
        transaction_isolation = REPEATABLE-READ 
       
        # 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. 
       
        # 內部(內存中)臨時表的最大大小  
       
        # 若是一個表增加到比此值更大,將會自動轉換爲基於磁盤的表.   
       
        # 此限制是針對單個表的,而不是總和.   
       
        tmp_table_size = 64M 
       
        # Enable binary logging. This is required for acting as a MASTER in a  
       
        # replication configuration. You also need the binary log if you need   
       
        # the ability to do point in time recovery from your latest backup. 
       
        # 打開二進制日誌功能.  
       
        # 在複製(replication)配置中,做爲MASTER主服務器必須打開此項   
       
        # 若是你須要從你最後的備份中作基於時間點的恢復,你也一樣須要二進制日誌.   
       
        log-bin=mysql-bin 
       
        # binary logging format - mixed recommended 
       
        #設定記錄二進制日誌的格式，有三種格式，基於語句 statement、 基於行 row、 混合方式 mixed  
       
        binlog_format=mixed 
       
        # If you're using replication with chained slaves (A->B->C), you need to  
       
        # enable this option on server B. It enables logging of updates done by   
       
        # the slave thread into the slave's binary log. 
       
        # 若是你在使用鏈式從服務器結構的複製模式 (A->B->C),  
       
        # 你須要在服務器B上打開此項.   
       
        # 此選項打開在從線程上重作過的更新的日誌,   
       
        # 並將其寫入從服務器的二進制日誌.   
       
        #log_slave_updates 
       
        # Enable the full query log. Every query (even ones with incorrect  
       
        # syntax) that the server receives will be logged. This is useful for   
       
        # debugging, it is usually disabled in production use. 
       
        # 打開查詢日誌. 全部的由服務器接收到的查詢 (甚至對於一個錯誤語法的查詢)  
       
        # 都會被記錄下來. 這對於調試很是有用, 在生產環境中經常關閉此項.   
       
        #log #默認是沒有開啓的，會影響服務器性能 
       
        # Print warnings to the error log file.  If you have any problem with  
       
        # MySQL you should enable logging of warnings and examine the error log   
       
        # for possible explanations. 
       
        # 將警告打印輸出到錯誤log文件. 若是你對於MySQL有任何問題  
       
        # 你應該打開警告log而且仔細審查錯誤日誌,查出可能的緣由.   
       
        #log_warnings 
       
        # Log slow queries. Slow queries are queries which take more than the  
       
        # amount of time defined in "long_query_time" or which do not use   
       
        # indexes well, if log_short_format is not enabled. It is normally good idea   
       
        # to have this turned on if you frequently add new queries to the   
       
        # system. 
       
        # 記錄慢速查詢. 慢速查詢是指消耗了比 「long_query_time」 定義的更多時間的查詢.  
       
        # 若是 log_long_format 被打開,那些沒有使用索引的查詢也會被記錄.   
       
        # 若是你常常增長新查詢到已有的系統內的話. 通常來講這是一個好主意   
       
        slow_query_log 
       
        # All queries taking more than this amount of time (in seconds) will be  
       
        # trated as slow. Do not use "1" as a value here, as this will result in   
       
        # even very fast queries being logged from time to time (as MySQL   
       
        # currently measures time with second accuracy only).   
       
        # 全部的使用了比這個時間(以秒爲單位)更多的查詢會被認爲是慢速查詢.   
       
        # 不要在這裏使用」1″, 不然會致使全部的查詢,甚至很是快的查詢頁被記錄下來(因爲MySQL 目前時間的精確度只能達到秒的級別). 
       
        long_query_time = 2 
       
        # ***  Replication related settings  # *** 主從複製相關的設置 
       
        # Unique server identification number between 1 and 2^32-1. This value  
       
        # is required for both master and slave hosts. It defaults to 1 if   
       
        # "master-host" is not set, but will MySQL will not function as a master   
       
        # if it is omitted. 
       
        # 惟一的服務辨識號,數值位於 1 到 2^32-1之間.  
       
        # 此值在master和slave上都須要設置.   
       
        # 若是 「master-host」 沒有被設置,則默認爲1, 可是若是忽略此選項,MySQL不會做爲master生效.   
       
        server- 
        id 
        = 1 
       
        # Replication Slave (comment out master section to use this) #複製的Slave (去掉master段的註釋來使其生效)  
       
        #   
       
        # To configure this host as a replication slave, you can choose between   
       
        # two methods : #爲了配置此主機做爲複製的slave服務器,你能夠選擇兩種方法:   
       
        #   
       
        # 1) Use the CHANGE MASTER TO command (fully described in our manual) -   
       
        #    the syntax is: #使用 CHANGE MASTER TO 命令 (在咱們的手冊中有完整描述) -   
       
        # 語法以下: 
       
        #  
       
        #    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,   
       
        #    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;   
       
        #   
       
        #    where you replace <host>, <user>, <password> by quoted strings and   
       
        #    <port> by the master's port number (3306 by default).   
       
        #    你須要替換掉 , , 等被尖括號包圍的字段以及使用master的端口號替換 (默認3306).   
       
        #    Example: 案例   
       
        #   
       
        #    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,   
       
        #    MASTER_USER='joe', MASTER_PASSWORD='secret';   
       
        #   
       
        # OR 或者   
       
        #   
       
        # 2) Set the variables below. However, in case you choose this method, then   
       
        #    start replication for the first time (even unsuccessfully, for example   
       
        #    if you mistyped the password in master-password and the slave fails to   
       
        #    connect), the slave will create a master.info file, and any later   
       
        #    changes in this file to the variable values below will be ignored and   
       
        #    overridden by the content of the master.info file, unless you shutdown   
       
        #    the slave server, delete master.info and restart the slaver server.   
       
        #    For that reason, you may want to leave the lines below untouched   
       
        #    (commented) and instead use CHANGE MASTER TO (see above)   
       
        # 
       
        #設置如下的變量. 不論如何, 在你選擇這種方法的狀況下, 而後第一次啓動複製(甚至不成功的狀況下,  
       
        # 例如若是你輸入錯密碼在master-password字段而且slave沒法鏈接),   
       
        # slave會建立一個 master.info 文件,而且以後任何對於包含在此文件內的參數的變化都會被忽略   
       
        # 而且由 master.info 文件內的內容覆蓋, 除非你關閉slave服務, 刪除 master.info 而且重啓slave 服務.   
       
        # 因爲這個緣由,你也許不想碰一下的配置(註釋掉的) 而且使用 CHANGE MASTER TO (查看上面) 來代替 
       
        # required unique id between 2 and 2^32 - 1   
       
        # (and different from the master)   
       
        # defaults to 2 if master-host is set   
       
        # but will not function as a slave if omitted 
       
        # 所須要的惟一id號位於 2 和 2^32 – 1之間  
       
        # (而且和master不一樣)   
       
        # 若是master-host被設置了.則默認值是2   
       
        # 可是若是省略,則不會生效   
       
        #server-id = 2   
       
        #   
       
        # The replication master for this slave – required 
       
        # 複製結構中的master – 必須  
       
        #master-host = <hostname>   
       
        #   
       
        # The username the slave will use for authentication when connecting   
       
        # to the master – required 
       
        # 當鏈接到master上時slave所用來認證的用戶名 – 必須 
       
        #master-user = <username>   
       
        #   
       
        # The password the slave will authenticate with when connecting to 
       
        # the master – required 
       
        # 當鏈接到master上時slave所用來認證的密碼 – 必須 
       
        #master-password = <password>  
       
        #   
       
        # The port the master is listening on.   
       
        # optional - defaults to 3306 
       
        # master監聽的端口.  
       
        # 可選 – 默認是3306   
       
        #master-port = <port> 
       
        # Make the slave read-only. Only users with the SUPER privilege and the  
       
        # replication slave thread will be able to modify data on it. You can   
       
        # use this to ensure that no applications will accidently modify data on   
       
        # the slave instead of the master 
       
        # 使得slave只讀.只有用戶擁有SUPER權限和在上面的slave線程可以修改數據.  
       
        # 你可使用此項去保證沒有應用程序會意外的修改slave而不是master上的數據 
       
        #read_only 
       
        #*** MyISAM Specific options 
       
        #*** MyISAM 相關選項  
       
        # 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. 
       
        # 關鍵詞緩衝的大小, 通常用來緩衝MyISAM表的索引塊.  
       
        # 不要將其設置大於你可用內存的30%,   
       
        # 由於一部份內存一樣被OS用來緩衝行數據   
       
        # 甚至在你並不使用MyISAM 表的狀況下, 你也須要仍舊設置起 8-64M 內存因爲它一樣會被內部臨時磁盤表使用.   
       
        key_buffer_size = 32M 
       
        # MyISAM uses special tree-like cache to make bulk inserts (that is,  
       
        # INSERT ... SELECT, INSERT ... VALUES (...), (...), ..., and LOAD DATA   
       
        # INFILE) faster. This variable limits the size of the cache tree in   
       
        # bytes per thread. Setting it to 0 will disable this optimisation.  Do   
       
        # not set it larger than "key_buffer_size" for optimal performance.   
       
        # This buffer is allocated when a bulk insert is detected. 
       
        # MyISAM 使用特殊的相似樹的cache來使得突發插入  
       
        # (這些插入是,INSERT … SELECT, INSERT … VALUES (…), (…), …, 以及 LOAD DATA   
       
        # INFILE) 更快. 此變量限制每一個進程中緩衝樹的字節數.   
       
        # 設置爲 0 會關閉此優化.   
       
        # 爲了最優化不要將此值設置大於 「key_buffer_size」.   
       
        # 當突發插入被檢測到時此緩衝將被分配.   
       
        bulk_insert_buffer_size = 64M 
       
        # This buffer is allocated when MySQL needs to rebuild the index in  
       
        # REPAIR, OPTIMIZE, 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. 
       
        # 此緩衝當MySQL須要在 REPAIR, OPTIMIZE, ALTER 以及 LOAD DATA INFILE 到一個空表中引發重建索引時被分配.  
       
        # 這在每一個線程中被分配.因此在設置大值時須要當心.   
       
        myisam_sort_buffer_size = 128M 
       
        # 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). 
       
        # MySQL重建索引時所容許的最大臨時文件的大小 (當 REPAIR, ALTER TABLE 或者 LOAD DATA INFILE).  
       
        # 若是文件大小比此值更大,索引會經過鍵值緩衝建立(更慢)   
       
        myisam_max_sort_file_size = 10G 
       
        # If a table has more than one index, MyISAM can use more than one  
       
        # thread to repair them by sorting in parallel. This makes sense if you   
       
        # have multiple CPUs and plenty of memory. 
       
        # 若是一個表擁有超過一個索引, MyISAM 能夠經過並行排序使用超過一個線程去修復他們.  
       
        # 這對於擁有多個CPU以及大量內存狀況的用戶,是一個很好的選擇.   
       
        myisam_repair_threads = 1 
       
        # Automatically check and repair not properly closed MyISAM tables. 
       
        # 自動檢查和修復沒有適當關閉的 MyISAM 表.  
       
        myisam_recover 
       
        # *** INNODB Specific options *** 
       
        # *** INNODB 相關選項 *** 
       
        # 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. 
       
        # 若是你的MySQL服務包含InnoDB支持可是並不打算使用的話,  
       
        # 使用此選項會節省內存以及磁盤空間,而且加速某些部分   
       
        #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. 
       
        # 附加的內存池被InnoDB用來保存 metadata 信息  
       
        # 若是InnoDB爲此目的須要更多的內存,它會開始從OS這裏申請內存.   
       
        # 因爲這個操做在大多數現代操做系統上已經足夠快, 你通常不須要修改此值.   
       
        # SHOW INNODB STATUS 命令會顯示當先使用的數量.   
       
        innodb_additional_mem_pool_size = 16M 
       
        # 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使用一個緩衝池來保存索引和原始數據, 不像 MyISAM.   
       
        # 這裏你設置越大,你在存取表裏面數據時所須要的磁盤I/O越少.   
       
        # 在一個獨立使用的數據庫服務器上,你能夠設置這個變量到服務器物理內存大小的80%   
       
        # 不要設置過大,不然,因爲物理內存的競爭可能致使操做系統的換頁顛簸.   
       
        # 注意在32位系統上你每一個進程可能被限制在 2-3.5G 用戶層面內存限制,   
       
        # 因此不要設置的過高. 
       
        innodb_buffer_pool_size = 2G 
       
        # InnoDB stores data in one or more data files forming the tablespace.  
       
        # If you have a single logical drive for your data, a single   
       
        # autoextending file would be good enough. In other cases, a single file   
       
        # per device is often a good choice. You can configure InnoDB to use raw   
       
        # disk partitions as well - please refer to the manual for more info   
       
        # about this. 
       
        # InnoDB 將數據保存在一個或者多個數據文件中成爲表空間.  
       
        # 若是你只有單個邏輯驅動保存你的數據,一個單個的自增文件就足夠好了.   
       
        # 其餘狀況下.每一個設備一個文件通常都是個好的選擇.   
       
        # 你也能夠配置InnoDB來使用裸盤分區 – 請參考手冊來獲取更多相關內容   
       
        innodb_data_file_path = ibdata1:10M:autoextend 
       
        # Set this option if you would like the InnoDB tablespace files to be  
       
        # stored in another location. By default this is the MySQL datadir. 
       
        # 設置此選項若是你但願InnoDB表空間文件被保存在其餘分區.  
       
        # 默認保存在MySQL的datadir中.   
       
        #innodb_data_home_dir = <directory> 
       
        # Number of IO threads to use for async IO operations. This value is  
       
        # hardcoded to 8 on Unix, but on Windows disk I/O may benefit from a   
       
        # larger number. 
       
        # 用來同步IO操做的IO線程的數量. This value is  
       
        # 此值在Unix下被硬編碼爲8,可是在Windows磁盤I/O可能在一個大數值下表現的更好.   
       
        innodb_write_io_threads = 8   
       
        innodb_read_io_threads = 8 
       
        # If you run into InnoDB tablespace corruption, setting this to a nonzero  
       
        # value will likely help you to dump your tables. Start from value 1 and   
       
        # increase it until you're able to dump the table successfully. 
       
        # 若是你發現InnoDB表空間損壞, 設置此值爲一個非零值可能幫助你導出你的表.  
       
        # 從1開始而且增長此值知道你可以成功的導出表.   
       
        #innodb_force_recovery=1 
       
        # 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. 
       
        # 在InnoDb核心內的容許線程數量.  
       
        # 最優值依賴於應用程序,硬件以及操做系統的調度方式.   
       
        # 太高的值可能致使線程的互斥顛簸.   
       
        innodb_thread_concurrency = 16 
       
        # 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. 
       
        # 若是設置爲1 ,InnoDB會在每次提交後刷新(fsync)事務日誌到磁盤上,  
       
        # 這提供了完整的ACID行爲.   
       
        # 若是你願意對事務安全折衷, 而且你正在運行一個小的食物, 你能夠設置此值到0或者2來減小由事務日誌引發的磁盤I/O   
       
        # 0表明日誌只大約每秒寫入日誌文件而且日誌文件刷新到磁盤.   
       
        # 2表明日誌寫入日誌文件在每次提交後,可是日誌文件只有大約每秒纔會刷新到磁盤上.   
       
        innodb_flush_log_at_trx_commit = 1 
       
        # Speed up InnoDB shutdown. This will disable InnoDB to do a full purge  
       
        # and insert buffer merge on shutdown. It may increase shutdown time a   
       
        # lot, but InnoDB will have to do it on the next startup instead. 
       
        # 加速InnoDB的關閉. 這會阻止InnoDB在關閉時作全清除以及插入緩衝合併.  
       
        # 這可能極大增長關機時間, 可是取而代之的是InnoDB可能在下次啓動時作這些操做.   
       
        #innodb_fast_shutdown 
       
        # 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). 
       
        # 用來緩衝日誌數據的緩衝區的大小.  
       
        # 當此值快滿時, InnoDB將必須刷新數據到磁盤上.   
       
        # 因爲基本上每秒都會刷新一次,因此沒有必要將此值設置的太大(甚至對於長事務而言)   
       
        innodb_log_buffer_size = 8M 
       
        # 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. 
       
        # 在日誌組中每一個日誌文件的大小.  
       
        # 你應該設置日誌文件總合大小到你緩衝池大小的25%~100%   
       
        # 來避免在日誌文件覆寫上沒必要要的緩衝池刷新行爲.   
       
        # 不論如何, 請注意一個大的日誌文件大小會增長恢復進程所須要的時間.   
       
        innodb_log_file_size = 256M 
       
        # Total number of files in the log group. A value of 2-3 is usually good  
       
        # enough. 
       
        # 在日誌組中的文件總數.  
       
        # 一般來講2~3是比較好的.   
       
        innodb_log_files_in_group = 3 
       
        # Location of the InnoDB log files. Default is the MySQL datadir. You  
       
        # may wish to point it to a dedicated hard drive or a RAID1 volume for   
       
        # improved performance 
       
        # InnoDB的日誌文件所在位置. 默認是MySQL的datadir.  
       
        # 你能夠將其指定到一個獨立的硬盤上或者一個RAID1捲上來提升其性能   
       
        #innodb_log_group_home_dir 
       
        # Maximum allowed percentage of dirty pages in the InnoDB buffer pool.  
       
        # If it is reached, InnoDB will start flushing them out agressively to   
       
        # not run out of clean pages at all. This is a soft limit, not   
       
        # guaranteed to be held. 
       
        # 在InnoDB緩衝池中最大容許的髒頁面的比例.  
       
        # 若是達到限額, InnoDB會開始刷新他們防止他們妨礙到乾淨數據頁面.   
       
        # 這是一個軟限制,不被保證絕對執行.   
       
        innodb_max_dirty_pages_pct = 90 
       
        # The flush method InnoDB will use for Log. The tablespace always uses  
       
        # doublewrite flush logic. The default value is "fdatasync", another   
       
        # option is "O_DSYNC". 
       
        # InnoDB用來刷新日誌的方法.  
       
        # 表空間老是使用雙重寫入刷新方法   
       
        # 默認值是 「fdatasync」, 另外一個是 「O_DSYNC」.   
       
        #innodb_flush_method=O_DSYNC 
       
        # How long an InnoDB transaction should wait for a lock to be granted  
       
        # before being rolled back. InnoDB automatically detects transaction   
       
        # deadlocks in its own lock table and rolls back the transaction. If you   
       
        # use the LOCK TABLES command, or other transaction-safe storage engines   
       
        # than InnoDB in the same transaction, then a deadlock may arise which   
       
        # InnoDB cannot notice. In cases like this the timeout is useful to   
       
        # resolve the situation. 
       
        # 在被回滾前,一個InnoDB的事務應該等待一個鎖被批准多久.  
       
        # InnoDB在其擁有的鎖表中自動檢測事務死鎖而且回滾事務.   
       
        # 若是你使用 LOCK TABLES 指令, 或者在一樣事務中使用除了InnoDB之外的其餘事務安全的存儲引擎   
       
        # 那麼一個死鎖可能發生而InnoDB沒法注意到.   
       
        # 這種狀況下這個timeout值對於解決這種問題就很是有幫助.   
       
        innodb_lock_wait_timeout = 120 
       
        [mysqldump]   
       
        # Do not buffer the whole result set in memory before writing it to   
       
        # file. Required for dumping very large tables 
       
        # 不要在將內存中的整個結果寫入磁盤以前緩存. 在導出很是巨大的表時須要此項  
       
        quick 
       
        max_allowed_packet = 16M 
       
        [mysql]  
       
        no-auto-rehash 
       
        # Only allow UPDATEs and DELETEs that use keys. 
       
        # 僅僅容許使用鍵值的 UPDATEs 和 DELETEs .  
       
        #safe-updates 
       
        [myisamchk]  
       
        key_buffer_size = 512M   
       
        sort_buffer_size = 512M   
       
        read_buffer = 8M   
       
        write_buffer = 8M 
       
        [mysqlhotcopy]  
       
        interactive-timeout 
       
        [mysqld_safe]  
       
        # Increase the amount of open files allowed per process. Warning: Make   
       
        # sure you have set the global system limit high enough! The high value   
       
        # is required for a large number of opened tables 
       
        # 增長每一個進程的可打開文件數量.  
       
        # 警告: 確認你已經將全系統限制設定的足夠高!   
       
        # 打開大量表須要將此值設大   
       
        open 
        -files-limit = 8192

3、配置文件優化（根據實際狀況優化）

說明，上文中我對my-innodb-heavy-4G.cnf中默認的全部選項進行了說明，下面我就根據咱們公司的實際狀況進行優化！

1.服務器的運行環境

硬件服務器：Dell R710，雙至強E5620 CPU、16G內存、6*500G硬盤
操做系統：CentOS5.5 X86_64 系統
Mysql版本：MySQL 5.5.32
適用於：日IP 100-200W ，日PV 200-500W 的站點

2.具體優化配置以下

 
        [client]  
       
        port        = 3306   
       
        socket        =  
        /tmp/mysql 
        .sock 
       
        default-character- 
        set 
        = utf8  
        #設置客戶端的字符編碼 
       
        [mysqld] 
       
        # generic configuration options  
       
        port        = 3306   
       
        socket        =  
        /tmp/mysql 
        .sock 
       
        #*** char set *** 
       
        character- 
        set 
        -server = utf8  
        #設置服務器端的字符編碼 
       
        #*** network *** 
       
        back_log = 512 
       
        #skip-networking #默認沒有開啓 
       
        max_connections = 3000 
       
        max_connect_errors = 30 
       
        table_open_cache = 4096 
       
        #external-locking #默認沒有開啓 
       
        max_allowed_packet = 32M 
       
        max_heap_table_size = 128 M 
       
        # *** global cache *** 
       
        read_buffer_size = 8M 
       
        read_rnd_buffer_size = 64M 
       
        sort_buffer_size = 16M 
       
        join_buffer_size = 16M 
       
        # *** thread *** 
       
        thread_cache_size = 16 
       
        thread_concurrency = 8 
       
        thread_stack = 512K 
       
        # *** query  cache *** 
       
        query_cache_size = 128M 
       
        query_cache_limit = 4M 
       
        # *** index *** 
       
        ft_min_word_len = 8 
       
        #memlock #默認沒有開啓 
       
        default-storage-engine = INNODB 
       
        transaction_isolation = REPEATABLE-READ 
       
        # *** tmp table *** 
       
        tmp_table_size = 64M 
       
        # *** bin log *** 
       
        log-bin=mysql-bin 
       
        binlog_cache_size = 4M 
       
        binlog_format=mixed 
       
        #log_slave_updates #默認沒有開啓 
       
        #log #默認沒有開啓，此處是查詢日誌，開啓會影響服務器性能 
       
        log_warnings  
        #開啓警告日誌 
       
        # *** slow query log *** 
       
        slow_query_log 
       
        long_query_time = 10 
       
        # ***  Replication related settings 
       
        server- 
        id 
        = 1 
       
        #server-id = 2  
       
        #master-host = <hostname>   
       
        #master-user = <username>   
       
        #master-password = <password>   
       
        #master-port = <port> 
       
        #read_only 
       
        #*** MyISAM Specific options 
       
        key_buffer_size = 128M 
       
        bulk_insert_buffer_size = 256M 
       
        myisam_sort_buffer_size = 256M 
       
        myisam_max_sort_file_size = 10G 
       
        myisam_repair_threads = 1 
       
        myisam_recover 
       
        # *** INNODB Specific options *** 
       
        #skip-innodb #默認沒有開啓 
       
        innodb_additional_mem_pool_size = 64M 
       
        innodb_buffer_pool_size = 6G  
        #注意在32位系統上你每一個進程可能被限制在 2-3.5G 用戶層面內存限制, 因此不要設置的過高. 
       
        innodb_data_file_path = ibdata1:10M:autoextend 
       
        #innodb_data_home_dir = <directory> 
       
        innodb_write_io_threads = 8  
       
        innodb_read_io_threads = 8 
       
        #innodb_force_recovery=1 
       
        innodb_thread_concurrency = 16 
       
        innodb_flush_log_at_trx_commit = 2 
       
        #說明：innodb_flush_log_at_trx_commit = 2 若是是遊戲服務器，建議此值設置爲2；若是是對數據安全要求極高的應用，建議設置爲1；設置爲0性能最高，但若是發生故障，數據可能會有丟失的危險！默認值1的意思是每一次事務提交或事務外的指令都須要把日誌寫入（flush）硬盤，這是很費時的。特別是使用電池供電緩存（Battery backed up cache）時。設成2對於不少運用，特別是從MyISAM錶轉過來的是能夠的，它的意思是不寫入硬盤而是寫入系統緩存。日誌仍然會每秒flush到硬盤，因此你通常不會丟失超過1-2秒的更新。設成0會更快一點，但安全方面比較差，即便MySQL掛了也可能會丟失事務的數據。而值2只會在整個操做系統掛了時纔可能丟數據。 
       
        #innodb_fast_shutdown 
       
        innodb_log_buffer_size = 16M 
       
        innodb_log_file_size = 512M 
       
        innodb_log_files_in_group = 3 
       
        #innodb_log_group_home_dir 
       
        innodb_max_dirty_pages_pct = 90 
       
        #innodb_flush_method=O_DSYNC 
       
        innodb_lock_wait_timeout = 120 
       
        [mysqldump]   
       
        quick 
       
        max_allowed_packet = 32M 
       
        [mysql]  
       
        no-auto-rehash 
       
        [myisamchk]  
       
        key_buffer_size = 2048M   
       
        sort_buffer_size = 2048M   
       
        read_buffer = 32M   
       
        write_buffer = 32M 
       
        [mysqlhotcopy]  
       
        interactive-timeout 
       
        [mysqld_safe]  
       
        open 
        -files-limit = 10240

3.總結

MySQL 配置文件的優化是根據線上環境的實際須要進行優化，不能隨便沒有根據的進行優化，寫這篇博文就是給博友們一些參考！

4.MySQL狀態查看的經常使用命令

 
        mysql> show status;  
        #顯示狀態信息  
       
        mysql> show variables;  
        #顯示系統變量   
       
        mysql> show engines;  
        #查看全部引擎 
       
        mysql> show engine innodb status;  
        #顯示InnoDB存儲引擎的狀態