mysql性能优化之table_open_cache

作者：admin 发布于：2014-7-15 14:30 Tuesday 分类：网络转载

mysql> show variables like "table%"; +-------------------------+--------+ | Variable_name | Value | +-------------------------+--------+ | table_definition_cache | 256 | | table_lock_wait_timeout | 50 | | table_open_cache | 1024 | | table_type | InnoDB | +-------------------------+--------+ 4 rows in set (0.00 sec) table_open_cache ：mysql每打开一个表，都会读入一些数据到table_open_cache 缓存 中 当mysql在这个缓存中找不到相应的信息时，才会去磁盘上直接读取。 mysql> show status like "open%"; +--------------------------+----------+ | Variable_name | Value | +--------------------------+----------+ | Open_files | 66 | | Open_streams | 0 | | Open_table_definitions | 135 | | Open_tables | 302 | | Opened_files | 86399846 | | Opened_table_definitions | 0 | | Opened_tables | 0 | +--------------------------+----------+ 7 rows in set (0.00 sec) Open_tables 当前打开的表数目 302 。table_open_cache 1024 。所有现在没必要对缓存进行调整。 mysql> show variables like "thread%"; ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect... Connection id: 81208905 Current database: ZXX +-------------------+---------------------------+ | Variable_name | Value | +-------------------+---------------------------+ | thread_cache_size | 64 | | thread_handling | one-thread-per-connection | | thread_stack | 196608 | +-------------------+---------------------------+ 3 rows in set (0.04 sec) 每当客户端连接到mysql数据库，mysql数据库就会创建以个线程为它服务 但是首先mysql回去thread_cache中寻找可用的线程，找不到才会创建新的线程 当前线程状况： mysql> show status like "thread%"; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | Threads_cached | 61 | | Threads_connected | 3 | | Threads_created | 2371 | | Threads_running | 3 | +-------------------+-------+

标签: table_open_cache