MySQL中的INFORMATION_SCHEMA.key_column_usage性能不佳

Question

我正在运行MySQL的5.5.11版本,查询INFORMATION_SCHEMA.key_column_usage表时的性能非常糟糕.

我有一个简单的选择请求:

SELECT REFERENCED_TABLE_NAME
       , TABLE_NAME AS TableName
       , COLUMN_NAME AS ColumnName
       , CONSTRAINT_SCHEMA AS Db 
FROM INFORMATION_SCHEMA.key_column_usage 

平均需要8秒才能返回400行.这是一个知道问题吗？如果是这样,有没有办法提高性能(补丁可能？).

Answer 1

By using the tip given there : http://www.mysqlperformanceblog.com/2011/12/23/solving-information_schema-slowness/

I switched from seconds to a hundred millisecond for the same query. This setting, saved my day :

innodb_stats_on_metadata=0