mysql启动后自动关闭

通过查看data目录的错误日志发现

Version: '5.5.45'  socket: ''  port: 3306  MySQL Community Server (GPL)
160422  5:50:29 InnoDB: Unable to allocate memory of size 1065024.
160422  5:50:29  InnoDB: Assertion failure in thread 4256 in file mem0mem.c line 361
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.

160422 5:50:29 InnoDB: Unable to allocate memory of size 1065024.
160422 5:50:29 InnoDB: Assertion failure in thread 4256 in file mem0mem.c line 361发现无法分配内存；
原因是因为配置文件里 innodb_buffer_pool_size太大了，虽然机器内存是256G， innodb_buffer_pool_size配置的了86G应该没事儿，后来把 innodb_buffer_pool_size改成12G就解决了