Open tables

Some tables can't be cached, and there are also statistics for them. In MySQL versions older than 5.1.3, the option was called table_cache. It's now called table_open_cache in MariaDB.

To view the current status, enter the following command:

MariaDB [(none)]> SHOW global STATUS LIKE 'Open%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| Open_files               | 288   |
| Open_streams             | 0     |
| Open_table_definitions   | 329   |
| Open_tables              | 222   |
| Opened_files             | 767   |
| Opened_table_definitions | 296   |
| Opened_tables            | 525   |
| Opened_views             | 0     |
+--------------------------+-------+
8 rows in set (0.00 sec)

We can see here the number of currently opening tables (222) and those already opened (525). Check regularly that the opened tables are not growing too fast. If this is the case, you should consider increasing the allocated memory...