myisam

本文介绍了myisam_sort_buffer_size与sort_buffer_size的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是具有6GB RAM的服务器上的MySQL.我需要知道myisam_sort_buffer_size和sort_buffer_size有什么区别吗?

I am MySQL on server with 6GB RAM. I need to know what is the difference between myisam_sort_buffer_size and sort_buffer_size?

我为他们设置了以下尺寸:

I have following size set to them:

myisam_sort_buffer_size = 8M

myisam_sort_buffer_size = 8M

sort_buffer_size = 256M

sort_buffer_size = 256M

请还提及这些值是否合适或需要调整?

Please also mention if these values are fine or need adjustments?

谢谢

推荐答案

sort_buffer_size:

MySQL文档:

每个需要进行排序的会话都会分配一个该大小的缓冲区. sort_buffer_size并非特定于任何存储引擎，而是以一般方式进行优化.

Each session that needs to do a sort allocates a buffer of this size. sort_buffer_size is not specific to any storage engine and applies in a general manner for optimization.

您的sort_buffer_size值似乎很高.默认值为2M.我建议不要超过此值，因为提高性能会降低性能. 有人建议使用较小的值，例如256kB.要记住的一件事是，这是每个客户端会话，不是全局值.较大的值将快速累加.

Your sort_buffer_size value seems extremely high. The default is 2M. I'd recommend going no larger than that since there is a performance penalty for going higher. Some people recommend smaller values such as 256kB. One thing to remember is this is per-client-session, it's not a global value. Large values will add up fast.

myisam_sort_buffer_size:

MySQL文档:

在REPAIR TABLE期间对MyISAM索引排序或使用CREATE INDEX或ALTER TABLE创建索引时分配的缓冲区大小.

The size of the buffer that is allocated when sorting MyISAM indexes during a REPAIR TABLE or when creating indexes with CREATE INDEX or ALTER TABLE.

您的myisam_sort_buffer_size看起来不错.除非您要使用ALTER TABLE或REPAIR TABLE等重建索引，否则这将无关紧要.

Your myisam_sort_buffer_size seems fine. This won't be relevant unless you are rebuilding indexes using ALTER TABLE or REPAIR TABLE etc.