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; php100.Com
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 |
+------------------+-------+ phP100.Com
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;
+--------------------+ phP100.Com
| @@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 phP100.Com
-> ;
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 | PhP100.Com
| 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%'; PhP100.Com
+-------------------------+-------+
| Variable_name | Value |
+-------------------------+-------+
| Qcache_queries_in_cache | 1 |
+-------------------------+-------+
1 row in set (0.00 sec)
MySQL> show status like 'qcache_f%';
+--------------------+----------+
| Variable_name | Value |
+--------------------+----------+ PhP100.cOm
| 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。
