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my.ini是什么？

my.ini是MySQL数据库中使用的配置文件，修改这个文件可以达到更新配置的目的。

my.ini存放在哪里？

my.ini存放在MySql安装的根目录，如图所示：

my.ini的具体内容介绍：

 1 # CLIENT SECTION
2 # ----------------------------------------------------------------------
3 #
4 # The following options will be read by MySQL client applications.
5 # Note that only client applications shipped by MySQL are guaranteed
6 # to read this section. If you want your own MySQL client program to
7 # honor these values, you need to specify it as an option during the
8 # MySQL client library initialization.
9 #
10 [client]
11
12 port=3306
13
14 [mysql]
15
16 default-character-set=gb2312

1.port参数表示的是MySQL数据库的端口，默认的端口是3306，如果你需要更改端口号的话，就可以通过在这里修改。

2.default-character-set参数是客户端默认的字符集，如果你希望它支持中文，可以设置成gbk或者utf8。

 1 # SERVER SECTION
2 # ----------------------------------------------------------------------
3 #
4 # The following options will be read by the MySQL Server. Make sure that
5 # you have installed the server correctly (see above) so it reads this
6 # file.
7 #
8 [mysqld]
9
10 # The TCP/IP Port the MySQL Server will listen on
11 port=3306
12
13
14 #Path to installation directory. All paths are usually resolved relative to this.
15 basedir="E:/Java/Mysql/"
16
17 #Path to the database root
18 datadir="C:/ProgramData/MySQL/MySQL Server 5.5/Data/"
19
20 # The default character set that will be used when a new schema or table is
21 # created and no character set is defined
22 character-set-server=gb2312
23
24 # The default storage engine that will be used when create new tables when
25 default-storage-engine=INNODB
26
27 # Set the SQL mode to strict
28 sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
29
30 # The maximum amount of concurrent sessions the MySQL server will
31 # allow. One of these connections will be reserved for a user with
32 # SUPER privileges to allow the administrator to login even if the
33 # connection limit has been reached.
34 max_connections=100
35
36 # Query cache is used to cache SELECT results and later return them
37 # without actual executing the same query once again. Having the query
38 # cache enabled may result in significant speed improvements, if your
39 # have a lot of identical queries and rarely changing tables. See the
40 # "Qcache_lowmem_prunes" status variable to check if the current value
41 # is high enough for your load.
42 # Note: In case your tables change very often or if your queries are
43 # textually different every time, the query cache may result in a
44 # slowdown instead of a performance improvement.
45 query_cache_size=0
46
47 # The number of open tables for all threads. Increasing this value
48 # increases the number of file descriptors that mysqld requires.
49 # Therefore you have to make sure to set the amount of open files
50 # allowed to at least 4096 in the variable "open-files-limit" in
51 # section [mysqld_safe]
52 table_cache=256
53
54 # Maximum size for internal (in-memory) temporary tables. If a table
55 # grows larger than this value, it is automatically converted to disk
56 # based table This limitation is for a single table. There can be many
57 # of them.
58 tmp_table_size=35M
59
60
61 # How many threads we should keep in a cache for reuse. When a client
62 # disconnects, the client's threads are put in the cache if there aren't
63 # more than thread_cache_size threads from before.  This greatly reduces
64 # the amount of thread creations needed if you have a lot of new
65 # connections. (Normally this doesn't give a notable performance
66 # improvement if you have a good thread implementation.)
68
69 #*** MyISAM Specific options
70
71 # The maximum size of the temporary file MySQL is allowed to use while
72 # recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
73 # If the file-size would be bigger than this, the index will be created
74 # through the key cache (which is slower).
75 myisam_max_sort_file_size=100G
76
77 # If the temporary file used for fast index creation would be bigger
78 # than using the key cache by the amount specified here, then prefer the
79 # key cache method.  This is mainly used to force long character keys in
80 # large tables to use the slower key cache method to create the index.
81 myisam_sort_buffer_size=69M
82
83 # Size of the Key Buffer, used to cache index blocks for MyISAM tables.
84 # Do not set it larger than 30% of your available memory, as some memory
85 # is also required by the OS to cache rows. Even if you're not using
86 # MyISAM tables, you should still set it to 8-64M as it will also be
87 # used for internal temporary disk tables.
88 key_buffer_size=55M
89
90 # Size of the buffer used for doing full table scans of MyISAM tables.
91 # Allocated per thread, if a full scan is needed.
94
95 # This buffer is allocated when MySQL needs to rebuild the index in
96 # REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
97 # into an empty table. It is allocated per thread so be careful with
98 # large settings.
99 sort_buffer_size=256K

1.port参数也是表示数据库的端口。

2.basedir参数表示MySQL的安装路径。

4.default-character-set参数表示默认的字符集，这个字符集是服务器端的。

5.default-storage-engine参数默认的存储引擎。

6.sql-mode参数表示SQL模式的参数，通过这个参数可以设置检验SQL语句的严格程度。

7.max_connections参数表示允许同时访问MySQL服务器的最大连接数，其中一个连接是保留的，留给管理员专用的。

8.query_cache_size参数表示查询时的缓存大小，缓存中可以存储以前通过select语句查询过的信息，再次查询时就可以直接从缓存中拿出信息。

9.table_cache参数表示所有进程打开表的总数。

10.tmp_table_size参数表示内存中临时表的总数。

12.myisam_max_sort_file_size参数表示MySQL重建索引时所允许的最大临时文件的大小。

13.myisam_sort_buffer_size参数表示重建索引时的缓存大小。

14.key_buffer_size参数表示关键词的缓存大小。

17.sort_buffer_size参数表示用于排序的缓存大小

 1 #*** INNODB Specific options ***
2
3
4 # Use this option if you have a MySQL server with InnoDB support enabled
5 # but you do not plan to use it. This will save memory and disk space
6 # and speed up some things.
7 #skip-innodb
8
9 # Additional memory pool that is used by InnoDB to store metadata
10 # information.  If InnoDB requires more memory for this purpose it will
11 # start to allocate it from the OS.  As this is fast enough on most
12 # recent operating systems, you normally do not need to change this
13 # value. SHOW INNODB STATUS will display the current amount used.
15
16 # If set to 1, InnoDB will flush (fsync) the transaction logs to the
17 # disk at each commit, which offers full ACID behavior. If you are
18 # willing to compromise this safety, and you are running small
19 # transactions, you may set this to 0 or 2 to reduce disk I/O to the
20 # logs. Value 0 means that the log is only written to the log file and
21 # the log file flushed to disk approximately once per second. Value 2
22 # means the log is written to the log file at each commit, but the log
23 # file is only flushed to disk approximately once per second.
24 innodb_flush_log_at_trx_commit=1
25
26 # The size of the buffer InnoDB uses for buffering log data. As soon as
27 # it is full, InnoDB will have to flush it to disk. As it is flushed
28 # once per second anyway, it does not make sense to have it very large
29 # (even with long transactions).
30 innodb_log_buffer_size=2M
31
32 # InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
33 # row data. The bigger you set this the less disk I/O is needed to
34 # access data in tables. On a dedicated database server you may set this
35 # parameter up to 80% of the machine physical memory size. Do not set it
36 # too large, though, because competition of the physical memory may
37 # cause paging in the operating system.  Note that on 32bit systems you
38 # might be limited to 2-3.5G of user level memory per process, so do not
39 # set it too high.
40 innodb_buffer_pool_size=107M
41
42 # Size of each log file in a log group. You should set the combined size
43 # of log files to about 25%-100% of your buffer pool size to avoid
44 # unneeded buffer pool flush activity on log file overwrite. However,
45 # note that a larger logfile size will increase the time needed for the
46 # recovery process.
47 innodb_log_file_size=54M
48
49 # Number of threads allowed inside the InnoDB kernel. The optimal value
50 # depends highly on the application, hardware as well as the OS
51 # scheduler properties. A too high value may lead to thread thrashing.
52 innodb_thread_concurrency=18

2.innodb_flush_log_at_trx_commit参数是设置提交日志的时机，若设置为1，InnoDB会在每次提交后将事务日志写到磁盘上。

3.innodb_log_buffer_size参数表示用来存储日志数据的缓存区的大小。

4.innodb_buffer_pool_size参数表示缓存的大小，InnoDB使用一个缓冲池类保存索引和原始数据。

5.innodb_log_file_size参数表示日志文件的大小。

posted on 2013-09-15 12:46 Ray_xujianguo 阅读(...) 评论(...) 编辑 收藏