1、关于table_open_cache

mysql>show status like 'open%tables';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Open_tables   | 157   |
| Opened_tables | 0     |
+---------------+-------+
2 rows in set (0.00 sec)
mysql>show variables like '%table_open_cache';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| table_open_cache | 2000  |
+------------------+-------+
1 row in set (0.00 sec)

当table_open_cache的值小于Open_tables的值的时候，就需要调高table_open_cache的值了。