如何确定mysql索引是否完全适合内存

How to figure out if mysql index fits entirely in memory(如何确定mysql索引是否完全适合内存)

问题描述

有没有办法确定 mysql 索引是否完全适合可用内存?如果是这样，我会怎么做:

Is there a way to determine whether a mysql index fits entirely in available memory? If so, how would I:

• 确定 mysql 索引的大小
• 确定应用程序的可用内存
• 确定索引是否完全适合内存

推荐答案

取决于存储引擎

SELECT FLOOR(SUM(index_length)/POWER(1024,2)) IndexSizesMB
FROM information_schema.tables WHERE engine='MyISAM' AND
table_schema NOT IN ('information_schema','performance_schema','mysql');

从key_buffer_size 中减去它.如果答案>0，然后是

Subtract that from key_buffer_size. If the answer > 0, then Yes

SELECT FLOOR(SUM(data_length+index_length)/POWER(1024,2)) InnoDBSizeMB
FROM information_schema.tables WHERE engine='InnoDB';

从innodb_buffer_pool_size 中减去它.如果答案>0，然后是

Subtract that from innodb_buffer_pool_size. If the answer > 0, then Yes

我在 DBA StackExchange

在专用数据库服务器上，确保 InnoDBSizeMB+IndexSizesMB 不超过 RAM 的 75%.

On a dedicated DB Server, make sure InnoDBSizeMB+IndexSizesMB does not exceed 75% of RAM.

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