一、MySQL的目錄結構
bin目錄：用於放置一些可執行文件，如mysql.exe、mysqld.exe、mysqlshow.exe等。
data目錄： 用於放置一些日志文件以及數據庫。
include目錄：用於放置一些頭文件，如：mysql.h、mysql_ername.h等。
lib目錄：用於放置一系列庫文件。
share目錄： 用於存放字符集、語言等信息。
my.ini： 是MySQL數據庫中使用的配置文件。
my-huge.ini：適合超大型數據庫的配置文件。
my-large.ini：適合大型數據庫的配置文件。
my-medium.ini：適合中型數據庫的配置文件。
my-small.ini：適合小型數據庫的配置文件。
my-template.ini：是配置文件的模板，MySQL配置向導將該配置文件中選擇項寫入到my.ini文件。
my-innodb-heavy-4G.ini：表示該配置文件只對於InnoDB存儲引擎有效，而且服務器的內存不能小於4GB。
二、mysql配置文件 my.ini
# 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
上面顯示的是客戶端的參數，[client]和[mysql]都是客戶端，下面是參數簡介：
1.port參數表示的是MySQL數據庫的端口，默認的端口是3306，如果你需要更改端口號的話，就可以通過在這里修改。
2.default-character-set參數是客戶端默認的字符集，如果你希望它支持中文，可以設置成gbk或者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
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
# created and no character set is defined
character-set-server=utf8
# The default storage engine that will be used when create new tableswhen
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
上面是服務器斷參數，一下是參數的簡介：
1.port參數也是表示數據庫的端口。
2.basedir參數表示MySQL的安裝路徑。
3.datadir參數表示MySQL數據文件的存儲位置，也是數據庫表的存放位置。
4.default-character-set參數表示默認的字符集，這個字符集是服務器端的。
5.default-storage-engine參數默認的存儲引擎。
6.sql-mode參數表示SQL模式的參數，通過這個參數可以設置檢驗SQL語句的嚴格程度。
7.max_connections參數表示允許同時訪問MySQL服務器的最大連接數，其中一個連接是保留的，留給管理員專用的。
8.query_cache_size參數表示查詢時的緩存大小，緩存中可以存儲以前通過select語句查詢過的信息，再次查詢時就可以直接從緩存中拿出信息。
9.table_cache參數表示所有進程打開表的總數。
10.tmp_table_size參數表示內存中臨時表的總數。
11.thread_cache_size參數表示保留客戶端線程的緩存。
12.myisam_max_sort_file_size參數表示MySQL重建索引時所允許的最大臨時文件的大小。
13.myisam_sort_buffer_size參數表示重建索引時的緩存大小。
14.key_buffer_size參數表示關鍵詞的緩存大小。
15.read_buffer_size參數表示MyISAM表全表掃描的緩存大小。
16.read_rnd_buffer_size參數表示將排序好的數據存入該緩存中。
17.sort_buffer_size參數表示用於排序的緩存大小
#*** 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存儲引擎使用的參數，一下是參數的簡介：
1.innodb_additional_mem_pool_size參數表示附加的內存池，用來存儲InnoDB表的內容。
2.innodb_flush_log_at_trx_commit參數是設置提交日志的時機，若設置為1，InnoDB會在每次提交后將事務日志寫到磁盤上。
3.innodb_log_buffer_size參數表示用來存儲日志數據的緩存區的大小。
4.innodb_buffer_pool_size參數表示緩存的大小，InnoDB使用一個緩沖池類保存索引和原始數據。
5.innodb_log_file_size參數表示日志文件的大小。
6.innodb_thread_concurrency參數表示在InnoDB存儲引擎允許的線程最大數。