MySQL performance optimization Open_Table configuration parameter configuration recommendations

In the MySQL database, Opened_tables represents the number of open tables, and the reasonable configuration of MySQL Open_Table is described in detail below.

MySQL Opened_tables represents the number of tables that have been opened. Here's how to properly configure MySQL Open_Table.

MySQL Open_Table

mysql> show global status like 'open%tables%';  

+---------------+-------+  

| Variable_name | Value |  

+---------------+-------+  

| Open_tables   | 919   |  

| Opened_tables | 1951  |  

+---------------+-------+ 

MySQL Open_tables represents the number of open tables. If the number of MySQL Opened_tables is too large, it means that the value of table_cache in the configuration (after 5.1.3, the value is called table_open_cache) may be too small. We query 1 for the value of server table_cache:

mysql> show variables like 'table_cache';  

+---------------+-------+  

| Variable_name | Value |  

+---------------+-------+  

| table_cache   | 2048  |  

+---------------+-------+ 

The appropriate value of MySQL Open_Table is:

Open_tables / Opened_tables * 100% >= 85%  

Open_tables / table_cache * 100%