下面允許我介紹一下MySQL的my.ini配置檔案：

my.ini是什麼？

　　my.ini是MySQL資料庫中使用的配置檔案，修改這個檔案可以達到更新配置的目的。

my.ini存放在哪裡？

　　my.ini存放在MySql安裝的根目錄，如圖所示：

my.ini的具體內容介紹：

# 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=gb2312
 

上面顯示的是客戶端的引數，[client]和[mysql]都是客戶端，下面是引數簡介：

　　1.port引數表示的是MySQL資料庫的埠，預設的埠是3306，如果你需要更改埠號的話，就可以通過在這裡修改。

　　2.default-character-set引數是客戶端預設的字符集，如果你希望它支援中文，可以設定成gbk或者utf8。

　　3.這裡還有一個password引數，在這裡設定了password引數的值就可以在登陸時不用輸入密碼直接進入

# 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="E:/Java/Mysql/"

#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=gb2312

# 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=35M


# 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=69M

# 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=55M

# 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
 

上面是伺服器斷引數，一下是引數的簡介：

　　1.port引數也是表示資料庫的埠。

　　2.basedir引數表示MySQL的安裝路徑。

　　3.datadir引數表示MySQL資料檔案的儲存位置，也是資料庫表的存放位置。

　　4.default-character-set引數表示預設的字符集，這個字符集是伺服器端的。

　　5.default-storage-engine引數預設的儲存引擎。

　　6.sql-mode引數表示SQL模式的引數，通過這個引數可以設定檢驗SQL語句的嚴格程度。

　　7.max_connections引數表示允許同時訪問MySQL伺服器的最大連線數，其中一個連線是保留的，留給管理員專用的。

　　8.query_cache_size引數表示查詢時的快取大小，快取中可以儲存以前通過select語句查詢過的資訊，再次查詢時就可以直接從快取中拿出資訊。

　　9.table_cache引數表示所有程序開啟表的總數。

　　10.tmp_table_size引數表示記憶體中臨時表的總數。

　　11.thread_cache_size引數表示保留客戶端執行緒的快取。

　　12.myisam_max_sort_file_size引數表示MySQL重建索引時所允許的最大臨時檔案的大小。

　　13.myisam_sort_buffer_size引數表示重建索引時的快取大小。

　　14.key_buffer_size引數表示關鍵詞的快取大小。

　　15.read_buffer_size引數表示MyISAM表全表掃描的快取大小。

　　16.read_rnd_buffer_size引數表示將排序好的資料存入該快取中。

　　17.sort_buffer_size引數表示用於排序的快取大小

#*** 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=3M

# 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=2M

# 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=107M

# 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=54M

# 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=18

上面是InnoDB儲存引擎使用的引數，一下是引數的簡介：

　　1.innodb_additional_mem_pool_size引數表示附加的記憶體池，用來儲存InnoDB表的內容。

　　2.innodb_flush_log_at_trx_commit引數是設定提交日誌的時機，若設定為1，InnoDB會在每次提交後將事務日誌寫到磁碟上。

　　3.innodb_log_buffer_size引數表示用來儲存日誌資料的快取區的大小。

　　4.innodb_buffer_pool_size引數表示快取的大小，InnoDB使用一個緩衝池類儲存索引和原始資料。

　　5.innodb_log_file_size引數表示日誌檔案的大小。

　　6.innodb_thread_concurrency引數表示在InnoDB儲存引擎允許的執行緒最大數。

注意：每次修改引數後，必須重新啟動MySQL服務才會有效。