MySQL查询缓存的实际应用代码示例_MySQL

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。