How to calculate a good InnoDB log file size
Peter wrote a post a while ago about choosing a good InnoDB log file size. Not to pick on Peter, but the post actually kind of talks about a lot of things and then doesn’t tell you how to choose a good log file size! So I thought I’d clarify it a little.
The basic point is that your log file needs to be big enough to let InnoDB optimize its I/O, but not so big that recovery takes a long time. That much Peter covered really well. But how do you choose that size? I’ll show you a rule of thumb that works pretty well.
In most cases, when people give you a formula for choosing a configuration setting, you should look at it with skepticism. But in this case you can calculate a reasonable value, believe it or not. Run these queries at your server’s peak usage time:
mysql> pager grep sequence
PAGER set to 'grep sequence'
mysql> show engine innodb status\G select sleep(60); show engine innodb status\G
Log sequence number 84 3836410803
1 row in set (0.06 sec)
1 row in set (1 min 0.00 sec)
Log sequence number 84 3838334638
1 row in set (0.05 sec)
Notice the log sequence number. That’s the total number of bytes written to the transaction log. So, now you can see how many MB have been written to the log in one minute. (The technique I showed here works on all versions of MySQL. In 5.0 and newer, you can just watch Innodb_os_log_written(可参考这里) from SHOW GLOBAL STATUS, too.)
mysql> select (3838334638 - 3836410803) / 1024 / 1024 as MB_per_min;
+------------+
| MB_per_min |
+------------+
| 1.83471203 |
+------------+
As a rough rule of thumb, you can make the log big enough that it can hold at most an hour or so of logs. That’s generally plenty of data for InnoDB to work with; an hour’s worth is more than enough so that it can reorder the writes to use sequential I/O during the flushing and checkpointing process. At this rate, this server could use about 110 MB of logs, total. Round it up to 128 for good measure. Since there are two log files by default, divide that in half, and now you can set
innodb_log_file_size=64M
Does that look surprisingly small? It might. I commonly see log file sizes in the gigabyte ranges. But that’s generally a mistake. The server I used for the measurements above is a big one doing a lot of work, not a toy. Log file sizes can’t be left at the default 5MB for any real workload, but they often don’t need to be as big as you might think, either.
If this rule-of-thumb calculation ends up showing you that your log file size ought to be many gigabytes, well, you have a more active write workload. Perhaps you’re inserting a lot of big rows or something. In this case you might want to make the log smaller so you don’t end up with GB of logs. But also realize this: the recovery time depends not only on the total log file size, but the number of entries in it. If you’re writing huge entries to the log, fewer log entries will fit into a given log file size, which will generally make recovery faster than you might expect with a big log.
However, most of the time when I run this calculation, I end up finding that the log file size needs to be a lot smaller than it’s configured to be. In part that’s because InnoDB’s log entries are very compact. The other reason is that the common advice to size the logs as a fraction of the buffer pool size is just wrong.
One final note: huge buffer pools or really unusual workloads may require bigger (or smaller!) log sizes. This is where formulas break down and judgment and experience are needed. But this “rule of thumb” is generally a good sane place to start.
参考:
http://www.percona.com/blog/2008/11/21/how-to-calculate-a-good-innodb-log-file-size/
How to calculate a good InnoDB log file size的更多相关文章
- 如何计算合适的InnoDB log file size
原文链接:http://www.mysqlperformanceblog.com/2008/11/21/how-to-calculate-a-good-innodb-log-file-size/ Pe ...
- innodb log file size 配置估算以及修改
root@localhost:(none) 06:22:17>pager grep seq PAGER set to 'grep seq' root@localhost:(none) 06:30 ...
- innodb log file与binlog的区别在哪里?
Q: innodb log file与binlog的区别在哪里?有人说1.mysql的innodb引擎实际上是包装了inno base存储引擎.而innodb log file是由 inno base ...
- InnoDB log file 设置多大合适?
简介: 数据库的东西,往往一个参数就牵涉N多知识点.所以简单的说一下.大家都知道innodb是支持事务的存储引擎.事务的四个特性ACID即原子性(atomicity),一致性(consistency) ...
- mariadb:InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes
mariadb 启动中 InnoDB: Error: log file ./ib_logfile0 is of different size 0 起因:线上正在运行的系统,因为需要调整性能,变更了my ...
- 报错问题:InnoDB: Error: log file ./ib_logfile0 is of different size
InnoDB: Error: log file ./ib_logfile0 is of different size bytesInnoDB: than specified in the .cnf f ...
- InnoDB: Error: log file .\ib_logfile0 is of different size 0 10485760 bytes
启动WAMP Server的时候报例如以下的错误: 140618 23:12:32 [Note] Plugin 'FEDERATED' is disabled. 140618 23:12:32 Inn ...
- 1025InnoDB log file 设置多大合适
转自 http://blog.csdn.net/langkeziju/article/details/51094289 数据库的东西,往往一个参数就牵涉N多知识点.所以简单的说一下.大家都知道inno ...
- MySQL启动报错Failed to open log (file 'D:\phpStudy\PHPTutorial\MySQL\data\mysql_bin.000045', errno 2)
MySQL报错 191105 9:39:07 [Note] Plugin 'FEDERATED' is disabled. 191105 9:39:07 InnoDB: The InnoDB memo ...
随机推荐
- 从对SAE的一次授权安全评估浅谈云安全
EMail: jianxin#80sec.comSite: http://www.80sec.comDate: 2011-12-20From: http://www.80sec.com/ [ 目录 ...
- Design Patterns
经典的<设计模式>一书归纳出23种设计模式,本文按<易学设计模式>一书归纳分类如下:1.创建型模式 前面讲过,社会化的分工越来越细,自然在软件设计方面也是如此,因此对象的创建和 ...
- 2016 - 1 - 20 runloop学习
一:Runloop基本知识 1.本质就是运行循环 2.基本作用: 2.1保证程序持续运行 2.2处理APP中的各种事件:触摸,定时器,selector... 2.3节省CPU资源,系统程序性能:它会让 ...
- GSM短信侦听的便宜方案
侦听GSM短信常用的是OsmocomBB + C118方案,主要是用luca/gsmmap分支.使用ccch_scan这个程序可以把通信封装成GSMTAP发给本机,然后用WireShark接收GSMT ...
- Swift编程规范
文档编号: 应用开发Swift编码规范 (版本v1.0.0) 成文信息 主题词: Swift开发编码规范 作 者: 周少停 文档类别: 开发规范 审 核: 批 准: 文档性质: 初稿 ...
- C语言基础:进制转换,变量,常量,表达式,基本数据类型,输出函数,输入函数,运算符. 分类: iOS学习 c语言基础 2015-06-10 21:39 25人阅读 评论(0) 收藏
二进制:以0b开头,只有0和1两种数字.如0101 十进制:0~9十个数字表示.如25 十六进制:以0~9,A~F表示,以0X开头.如0X2B 十进制转换为X进制:连除倒取余 X进制转换为十进制:按权 ...
- Bootstrap组件On和Off语法
$(document).on('click.bs.carousel.data-api','td',function(e){}) $(document).off('.carousel.data-api' ...
- 七、CCScene
CCScene一般情况是游戏里面的根节点,称之为"场景",运行游戏时需要通过CCDirector启动第一个场景.当然,游戏稍微复杂一点的话,可能会包含很多个场景,这就涉及到场景的切 ...
- 如何在UIAlertView中显示进度条
今天这个问题是,在一个iPhone程序中,我要在后台做大量的数据处理,希望在界面上显示一个进度条(Progress Bar)使得用户了解处理进度.这个进度条应该是在一个模态的窗口中,使界 今天这个问题 ...
- msp430 问题及解决记录
----------------------------- 2015.4.28 问题:开发板串口显示的内容为乱码 解决:使用的是原先产品主板的15200的波特率设置,但看来或者是开发板不支持11520 ...