第一步,我們找到mysql安裝文件下面的my.ini文件,打開可以看到第一句:
# MySQL Server Instance Configuration File
Mysql服務實例配置文件
好,咱們撇開那些不是那麼重要的字幕,直接進入重點,看看它可以配置些什麼,和到底配置了些什麼,那麼帶着這樣的心態,我們往下看。
CLIENT SECTION
客戶端章節:
[client]
port=3306 端口號=3306
[mysql]
default-character-set=latin1 默認字符編碼=latin1
SERVER SECTION
服務端章節
[mysqld]
# The TCP/IP Port the MySQL Server will listen on
TCP/IP Port 監聽mysql的端口號
port=3306
#Path to installation directory. All paths are usually resolved relative to this.
安裝目錄路徑 。所有的路徑都是作爲這個路徑的相對路徑。
basedir="E:/programfile/MySql5.1/"
#Path to the database root
數據庫數據的根路徑
datadir="C:/ProgramData/MySQL/MySQL Server 5.1/Data/"
# The default character set that will be used when a new schema or table is
# created and no character set is defined
默認的字符集編碼作用於當一個新的schema 或者表被創建的時候沒有指定字符集。
default-character-set=latin1
# The default storage engine that will be used when create new tables when
默認的存儲引擎作用於當創建新表的時候
default-storage-engine=INNODB
# Set the SQL mode to strict
設置嚴格的SQL模型
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.
Mysql 服務端允許最大的併發數,其中一個連接將留給用戶使用超級權限連接數據庫,即使連接數已經達到最高限額
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.
查詢緩存用於在緩存中SELECT結果,返回不是實際查詢數據庫的結果。
從緩存中查詢的結果會顯著的提升查詢速度,如果你有很多相同的查詢和很少改變表結構。
查看“Qcache_lowmem_prunes”狀態變量來檢查當前值對於你的負載是否足夠高。
NOTE:如果你的表結構經常改變或者,你每次查詢都不相同,那麼使用查詢緩存結果可能不是一個性能改進。
query_cache_size=15M
# 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]
所有的線程打開表的數量。
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.
臨時表最大內存大小。如果一個表生長大於這個值,它會自動轉換爲磁盤,這只是限制單個表,可以有很多個
tmp_table_size=18M
# 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.)
有很多線程我們應該保持在一個緩存裏以便重用。在沒有超過超過線程緩存大小之前,當一個客戶端斷開連接時,把客戶端線程放在緩存中。如果你有很多新的連接,那麼這大大降低了線程的數量創造需要。(如果你有一個好的改進線程實現方案,那麼這個並不會給出一個顯著的性能)
thread_cache_size=8
#*** MyISAM Specific options
MYISAM 特殊配置項
# 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臨時文件允許使用重建索引(在修復,修改表結構,導入數據文件時)的最大大小。
如果文件大小會比這個大,該指數將被創建通過鍵緩存(很慢)
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.
如果臨時文件用於快速創建索引將比使用鍵緩存更大,那麼鍵緩存的方法是很好的。這主要用於在比較大型的表使用緩慢的基礎上,使用長字符串創建索引。
myisam_sort_buffer_size=35M
# 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.
在MyISAM表裏用於緩存索引塊。不要把它設置爲大於你的可用內存的30%,因爲一些內存還需要由OS緩存行,即使您沒有使用MyISAM表,您仍然應該將其設置爲8 - 64 m,因爲它也會用於內部臨時磁盤表
key_buffer_size=8M
# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
MyISAM表用來做全表掃描的緩衝區大小
如果需要一個完整的掃描,就分配給每一個線程
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.
這個緩衝區是分配給:當MYSQL在需要修理,OPTIMZE,修改表結構語句以及導入加載數據
到一個空表時重建索引。它是分配給每個線程,所以在大型設置中要小心使用。
sort_buffer_size=256K
#*** INNODB Specific options ***
INNODB特殊項
INNODB保存數據目錄
innodb_data_home_dir="E:/MySQL Datafiles/"
# 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存儲元數據信息時的額外的內存池。如果需要更多的內存,InnoDB爲此它會分配它的操作系統內存。因爲在大多數操作系統中,這已經是足夠快的了,所以通常不需要修改這個值。SHOW INNODB STATUS會顯示當前的使用量
innodb_additional_mem_pool_size=2M
# 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.
如果設置爲1,InnoDB會在每個提交磁盤沖洗事務日誌,這提供了完整的ACID的行爲.
如果你想安全,並且正在執行一些小操作,你可以設置爲0或者2在減少磁盤I / O日誌。
#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).
這個大小用於緩衝InnoDB在緩衝日誌數據。一旦它滿了,InnoDB會在磁盤上釋放它。
它無論如何都會一秒緩衝一次,這對於非常大的日誌是沒有意義的。(即使有長事務)
innodb_log_buffer_size=1M
# 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,不像MyISAM,使用一個緩衝池來緩存的兩個索引和行數據。這個磁盤I / O設置的更大,需要訪問的數據表更少。在專用的數據庫服務器上你可以設置參數高達80%的機器的物理內存大小。不用把它設置的太大,不過,因爲在操作系統中競爭的物理內存可能導致內存不夠分。注意,32位系統上的你可能被限制在2 - 3.5g的用戶級內存,所以不要設置的太高。
innodb_buffer_pool_size=83M
# 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.
每個日誌文件在日誌組裏的大小。你應該將日誌文件大約爲25% - -100%緩衝池大小合併來避免不必要的緩衝池的緩衝行爲覆蓋日誌文件。然而,一個大的日誌文件將增加復甦過程的所需時間。
innodb_log_file_size=17M
# 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的內核允許多線程。最高性能取決於高的應用程序、硬件以及操作系統。
一個很高的值可能導致線程抖動
innodb_thread_concurrency=8
總結:Mysql數據庫,分INNODB和MYISAM存儲引擎,MYISAM不支持多線程,也就是說,當有一個鏈接在對某表進行存儲操作的時候,會自動鎖表。當這個鏈接操作完成以後,後面的鏈接才能繼續執行存儲操作。而INNODB支持多線程,只要不是自己手動鎖表,都不是出現類似MYISAM的情況。然後再查詢速度上,比如:select count(*) from table1;,MYISAM要強於INNODB,因爲,在表數據存進來的時候,MYISAM的引擎就會自動存儲一個該表的總數量等信息,那麼查詢的時候就會自動從那裏取得。一般MYISAM在統計數據時用的比較多
Mysql的my.ini文件
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