以下的文章主要介绍的是MySQL 查询缓存的实际应用代码以及查看MySQL 查询缓存的大小 ，碎片整理，清除缓存以及监视MySQL 查询缓存性能的相关内容的描述，以下就是具体内容的描述，希望在你今后的学习中会有所帮助。 MySQL> select @@query_cache_type; +--------------------+ | @@query_cache_type | +--------------------+ | ON | +--------------------+ MySQL> set query_cache_type=off; MySQL> set query_cache_type=on; MySQL> MySQL> select sql_cache id, title, body from article; MySQL> select sql_no_cache id, title, body from article; MySQL> show variables like 'have_query_cache'; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | have_query_cache | YES | +------------------+-------+ 1 row in set (0.00 sec) 　　查看MySQL 查询缓存的大小 MySQL> select @@global.query_cache_size; +---------------------------+ | @@global.query_cache_size | +---------------------------+ | 16777216 | +---------------------------+ 1 row in set (0.00 sec) MySQL> select @@query_cache_size; +--------------------+ | @@query_cache_size | +--------------------+ | 16777216 | +--------------------+ 1 row in set (0.00 sec) 　　查看最大缓存结果，如果结果集大于该数，不缓存。 MySQL> select @@global.query_cache_limit; +----------------------------+ | @@global.query_cache_limit | +----------------------------+ | 1048576 | +----------------------------+ 1 row in set (0.00 sec) 　　碎片整理 MySQL> flush query cache -> ; Query OK, 0 rows affected (0.00 sec) 　　清除缓存 MySQL> reset query cache -> ; Query OK, 0 rows affected (0.00 sec 　　监视MySQL 查询缓存性能： MySQL> flush tables; Query OK, 0 rows affected (0.04 sec) MySQL> show status like 'qcache%'; +-------------------------+----------+ | Variable_name | Value | +-------------------------+----------+ | Qcache_free_blocks | 1 | | Qcache_free_memory | 16768408 | | Qcache_hits | 6 | | Qcache_inserts | 36 | | Qcache_lowmem_prunes | 0 | | Qcache_not_cached | 86 | | Qcache_queries_in_cache | 0 | | Qcache_total_blocks | 1 | +-------------------------+----------+ 8 rows in set (0.06 sec) 　　看看当前缓存中有多少条信息： MySQL> show status like 'qcache_q%'; +-------------------------+-------+ | Variable_name | Value | +-------------------------+-------+ | Qcache_queries_in_cache | 0 | +-------------------------+-------+ 1 row in set (0.00 sec) MySQL> select sql_cache id, title, body from article; MySQL> show status like 'qcache_q%'; +-------------------------+-------+ | Variable_name | Value | +-------------------------+-------+ | Qcache_queries_in_cache | 1 | +-------------------------+-------+ 1 row in set (0.00 sec) MySQL> show status like 'qcache_f%'; +--------------------+----------+ | Variable_name | Value | +--------------------+----------+ | Qcache_free_blocks | 1 | | Qcache_free_memory | 16766728 | +--------------------+----------+ 2 rows in set (0.00 sec) 　　以上的相关内容就是对MySQL 查询缓存的介绍，望你能有所收获。