Mysql: 21 performance optimization best practices 1 [optimize your query cache] _ MySQL

Mysql: 21 performance optimization best practices 1 [optimize your query cache] bitsCN.com

Optimize your query for query cache

Query cache is enabled on most MySQL servers. This is one of the most effective ways to improve performance, and it is processed by the MySQL database engine. When many identical queries are executed multiple times, these query results are stored in a cache, the cache results are directly accessed for the same query in the future without having to operate the table.
The main problem here is that this is easy for programmers to ignore. Because some of our query statements will make MySQL not use cache. See the following example:

The difference between the preceding two SQL statements is CURDATE (). The query cache of MySQL does not work for this function. Therefore, SQL functions such as NOW (), RAND (), and other such functions do not enable the query cache, because the returned results of these functions are variable. Therefore, all you need is to use a variable to replace the MySQL function and enable the cache.

BitsCN.com