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mysql配置_MySQL

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Freigeben: 2016-05-30 17:10:06
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前言:《mysql配置》,在centOS上安装完成mysql后,自然是要对mysql进行配置,对于mysql来说,my.cnf可是很重要的,相当于画龙点睛的作用呢。

经常不经意间就发现文章被扣到各式各样的网站上面,甚是可恶!
那么人生何处不爬虫,爬虫请标http://blog.csdn.net/qing_gee
见贤思齐焉,见不贤而内自省也!

特此说明,我这个配置文件内容是结合我项目实战经验多次总结出来的王道,对提升mysql性能有着关键性的作用,当然了,这要看你的项目是否需要这样做喽。

这个文件里面的配置项目很多,我就一一说明了(主要是俺其实有一些也不懂,千万要笑啊,我是真不懂,不过我有问过度娘!),

<code class="language-shell hljs makefile">[client]
#no-beep
port=3306

[mysql]
default-character-set=utf8
socket          = /var/lib/mysql/mysql.sock

[mysqld]
# The TCP/IP Port the MySQL Server will listen on
port=3306
socket          = /var/lib/mysql/mysql.sock

character-set-server=utf8

#默认引擎设置为INNODB,这要看你的数据库是做什么用的
default-storage-engine=INNODB
#最大连接数,这个说实话,我没有测出来最合理的数值
max_connections = 500
#下面这两个参数就是禁用缓存查询,主要是因为我的数据库大量的写操作,所以设置了cache,反而会影响性能,也是基于理论上的,所以你大可不必相信。
query_cache_size=0
query_cache_type=0

#这几个数值,你千万要找度娘理论一下啊,我是说不清楚了
table_open_cache=2000
tmp_table_size=19M
thread_cache_size = 18
myisam_max_sort_file_size = 1G
myisam_sort_buffer_size=30M
key_buffer_size=8M
read_buffer_size = 512K
read_rnd_buffer_size = 1M
sort_buffer_size = 512k

#这个很重要了,对性能有着很大的影响,我会告诉你的。
innodb_flush_log_at_trx_commit=2

innodb_log_buffer_size=1M

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
innodb_buffer_pool_size=2G
innodb_buffer_pool_instances=1
#上面这两个参数对性能的作用我会论证给你的。

#这一块参数的作用我也忘的差不多了,所以度娘吧
innodb_log_file_size=48M
innodb_thread_concurrency=9
innodb_autoextend_increment=64
innodb_buffer_pool_instances=8
innodb_concurrency_tickets=5000
innodb_old_blocks_time=1000
innodb_open_files=300
innodb_stats_on_metadata=0
innodb_file_per_table=1
innodb_checksum_algorithm=0
flush_time=0
join_buffer_size=256K
max_connect_errors=100
max_allowed_packet = 16M
open_files_limit=4161
table_definition_cache=1400
binlog_row_event_max_size=8K

#二进制的类型,这个有很大学问,稍候我也会告诉你的。
binlog-format = MIXED

#事务锁时间,这个同样学问很大。
innodb_lock_wait_timeout = 20

#事务锁级别,这个学问同样很大很大啊
transaction-isolation = REPEATABLE-READ


binlog_cache_size = 1M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
#这个参数就是设置二进制文件的路径的,注意啊,注意啊!
log_bin=mysql-bin

server_id = 1

[mysqldump]
max_allowed_packet = 16M
</code>
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重点来了,下面这些内容,如果你没有看到,我觉得你错过了精彩,精彩啊,如果你错过了,我强烈抗议的,虽然抗议无效!

1.innodb_flush_log_at_trx_commit=2

Controls the balance between strict ACID compliance for commit operations, and higher performance<br /> that is possible when commit-related I/O operations are rearranged and done in batches. You can<br /> achieve better performance by changing the default value, but then you can lose up to a second of<br /> transactions in a crash.<br /> ? The default value of 1 is required for full ACID compliance. With this value, the contents of the InnoDB<br /> log buffer are written out to the log file at each transaction commit and the log file is flushed to disk.<br /> ? With a value of 0, the contents of the InnoDB log buffer are written to the log file approximately once<br /> per second and the log file is flushed to disk. No writes from the log buffer to the log file are performed<br /> at transaction commit. Once-per-second flushing is not 100% guaranteed to happen every second,<br /> due to process scheduling issues. Because the flush to disk operation only occurs approximately once<br /> per second, you can lose up to a second of transactions with any mysqld process crash.<br /> ? With a value of 2, the contents of the InnoDB log buffer are written to the log file after each transaction<br /> commit and the log file is flushed to disk approximately once per second. Once-per-second flushing<br /> is not 100% guaranteed to happen every second, due to process scheduling issues. Because the<br /> flush to disk operation only occurs approximately once per second.

大致的意思是将该属性主要是为数据库的ACID原则进行服务的,并且默认为1,但是实际情况下(我们项目是结合spring和mybatis,可能是某一方面设置不当),设置为2会提高很多的事务性能,从文档中可以看得出来,&ldquo;1的时候,innodb的缓存会在事务提交或者每秒钟时都会进行磁盘的刷新操作,2的时候,innodb缓存会在提交事务时写入到事务日志但不会刷新磁盘,然后在每秒钟时进行磁盘刷新操作&rdquo;,2要比1提高很多性能,但是对于隐患来说,我没有太好的理解,按照文档中给出的结果好像是&ldquo;在操作系统崩溃的时候,2的情况下,会丢失1秒的数据&rdquo;,但是仔细想想发生的时间节点,1.事务没有commit时,断电了,此时肯定数据是没有更新成功的,因为都还没有来得及写入事务日志,2.事务提交后,在写入事务日志的时候,发生断电,此时无论是参数的值是1还是2,都应该恢复不了数据了,3.每秒钟刷新磁盘时,发生断电,按照《高性能mysql》的字面意思,此时既然事务日志已经持久化了,那么重启后,数据是会自动恢复的。那么疑问来了,2和1的隐患到底在什么情况下会发生。

我在http://blog.csdn.net/qing_gee/article/details/42551179,这篇文章中有介绍。

2.innodb_buffer_pool_size=2G<br /> innodb_buffer_pool_instances=1

这两个参数,你必须得看看这个mysql:提升性能的最关键参数

3.binlog-format = MIXED

binlog_format=mixed:二进制日志的格式为mixed,该中模式是statement和row模式的结合体,注意查看我同事写的http://www.xx566.com/detail/177.html这篇文章,里面讲解了我们项目在二进制日志设置上遇到的问题和解决办法,如果遇到类似的问题后,会有所帮助。<br /> In MySQL 5.7, the default format is STATEMENT.<br /> You must have the SUPER privilege to set either the global or session binlog_format value.<br /> The rules governing when changes to this variable take effect and how long the effect lasts are the same<br /> as for other MySQL server system variables. See Section 13.7.4, &ldquo;SET Syntax&rdquo;, for more information.<br /> When MIXED is specified, statement-based replication is used, except for cases where only row-based<br /> replication is guaranteed to lead to proper results. For example, this happens when statements contain<br /> user-defined functions (UDF) or the UUID() function. An exception to this rule is that MIXED always<br /> uses statement-based replication for stored functions and triggers.

4.innodb_lock_wait_timeout = 20<br /> 你可以看看这个Transactional和mysql究竟有什么关系,你会明白的,我相信!

5.transaction-isolation = REPEATABLE-READ<br /> 高性能mysql札记:事务,这里面,我有大量的论证。

当然了,我之前也从各地摘录了一些关于参数介绍的,如果你觉得需要的话,我会给你地址的。mysql:配置参数优化建议

写到这,我觉得我的套路就要结束了,这些经验,我真想不说出来的!

最后啊,记得要重启mysql的不然,肯定是没有效果的。

<code class="language-shell hljs makefile"><code class="language-shell hljs ">service mysql restart</code></code>
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<code class="language-shell hljs "><strong>结语</strong>:分享知识是快乐的,我只好这样安慰自己吧,哈哈,其实我心态是很宽的,所谓“人逢知己千杯少”,我主要是想结交朋友的,哈哈。

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