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。