thread_cacheを50にしてみたらひどく効果があった。 mysql> show status like '%con%'; +----------------------+-------+ | Variable_name | Value | +----------------------+-------+ | Aborted_connects | 0 | | Connections | 33433 | | Max_used_connections | 32 | | Threads_connected | 1 | +----------------------+-------+ 4 rows in set (0.00 sec) mysql> show status like '%thre%'; +------------------------+-------+ | Variable_