MariaDB數據庫的緩存配置詳解

MariaDB是mysql數據庫被收購之後的團隊做的一款MariaDB數據庫了它和mysql數據庫有許我相的地方有緩存功能，下面我們來看MariaDB數據庫的緩存配置方法。

在這裡簡單介紹一下MariaDB的緩存相關參數。

have_query_cache

MariaDB [(none)]> SHOW VARIABLES LIKE 'have_query_cache';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| have_query_cache | YES   |
+------------------+-------+
1 row in set (0.00 sec)

query_cache_limit

MariaDB [(none)]> SHOW VARIABLES LIKE 'query_cache_limit';
+-------------------+---------+
| Variable_name     | Value   |
+-------------------+---------+
| query_cache_limit | 1048576 |
+-------------------+---------+
1 row in set (0.00 sec)

query_cache_min_res_unit

SHOW VARIABLES LIKE 'query_cache_min_res_unit';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| query_cache_min_res_unit | 4096  |
+--------------------------+-------+
1 row in set (0.00 sec)

query_cache_size

MariaDB [(none)]> SHOW VARIABLES LIKE 'query_cache_size';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| query_cache_size | 0     |
+------------------+-------+
1 row in set (0.00 sec)

query_cache_type

MariaDB [(none)]> SHOW VARIABLES LIKE 'query_cache_type';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| query_cache_type | ON    |
+------------------+-------+
1 row in set (0.00 sec)

query_cache_wlock_invalidate

MariaDB [(none)]> SHOW VARIABLES LIKE 'query_cache_wlock_invalidate';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| query_cache_wlock_invalidate | OFF   |
+------------------------------+-------+
1 row in set (0.00 sec)

確認查詢緩存情況

如何確認一個數據庫的查詢緩存情況，如命中率如何，配置的內存是否妥當？
MariaDB提供了一系列的SHOW STATUS命令來確認當前的查詢緩存狀態。

MariaDB [(none)]> SHOW STATUS LIKE 'Qcache%';
+-------------------------+-------+
| Variable_name           | Value |
+-------------------------+-------+
| Qcache_free_blocks      | 0     |
| Qcache_free_memory      | 0     |
| Qcache_hits             | 0     |
| Qcache_inserts          | 0     |
| Qcache_lowmem_prunes    | 0     |
| Qcache_not_cached       | 0     |
| Qcache_queries_in_cache | 0     |
| Qcache_total_blocks     | 0     |
+-------------------------+-------+
8 rows in set (0.00 sec)

清除查詢緩存

MariaDB [(none)]> RESET QUERY CACHE;
Query OK, 0 rows affected (0.00 sec)