启动时报错信息：
ERROR! MySQL server PID file could not be found!

Starting MySQL.. ERROR! The server quit without updating PID file (/usr/local/mysql/var/AYXXXXXXXXXXX.pid).

mysql/data/iZ253guleydZ.err 日志报错信息:

190515 23:48:13 mysqld_safe Starting mysqld daemon with databases from /alidata/server/mysql/data

2019-05-15 23:48:13 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use –explicit_defaults_for_timestamp server option (see documentation for more details).

2019-05-15 23:48:14 9667 [Note] Plugin ‘FEDERATED’ is disabled.

2019-05-15 23:48:14 9667 [Note] InnoDB: The InnoDB memory heap is disabled

2019-05-15 23:48:14 9667 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins

2019-05-15 23:48:14 9667 [Note] InnoDB: Compressed tables use zlib 1.2.3

2019-05-15 23:48:14 9667 [Note] InnoDB: Using Linux native AIO

2019-05-15 23:48:14 9667 [Note] InnoDB: Using CPU crc32 instructions

2019-05-15 23:48:14 9667 [Note] InnoDB: Initializing buffer pool, size = 128.0M

InnoDB: mmap(549453824 bytes) failed; errno 12

2019-05-15 23:48:14 9667 [ERROR] InnoDB: Cannot allocate memory for the buffer pool

2019-05-15 23:48:14 9667 [ERROR] Plugin ‘InnoDB’ init function returned error.

2019-05-15 23:48:14 9667 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.

2019-05-15 23:48:14 9667 [ERROR] Unknown/unsupported storage engine: InnoDB

2019-05-15 23:48:14 9667 [ERROR] Aborting

2019-05-15 23:48:14 9667 [Note] Binlog end

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘partition’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘ARCHIVE’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘BLACKHOLE’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘PERFORMANCE_SCHEMA’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_DATAFILES’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_TABLESPACES’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_FOREIGN_COLS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_FOREIGN’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_FIELDS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_COLUMNS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_INDEXES’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_TABLESTATS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_SYS_TABLES’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_INDEX_TABLE’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_INDEX_CACHE’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_CONFIG’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_BEING_DELETED’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_DELETED’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_FT_DEFAULT_STOPWORD’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_METRICS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_BUFFER_POOL_STATS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_BUFFER_PAGE_LRU’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_BUFFER_PAGE’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMP_PER_INDEX_RESET’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMP_PER_INDEX’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMPMEM_RESET’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMPMEM’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMP_RESET’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_CMP’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_LOCK_WAITS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_LOCKS’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘INNODB_TRX’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘CSV’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘MEMORY’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘MyISAM’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘MRG_MYISAM’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘sha256_password’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘mysql_old_password’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘mysql_native_password’

2019-05-15 23:48:14 9667 [Note] Shutting down plugin ‘binlog’

2019-05-15 23:48:14 9667 [Note] /alidata/server/mysql/bin/mysqld: Shutdown complete

190515 23:48:14 mysqld_safe mysqld from pid file /alidata/server/mysql/data/iZ253guleydZ.pid ended

情况说明：mysql可以启动，但是运行一段时间后自动断开(挂掉)

解决办法：

观察内存是否有占满或95%以上使用率，mysql服务是否在高使用率是挂掉，如果是，可以考虑适当增加内存。如果不是自行百度结果

辅助命令：

一、 启动
1、使用 service 启动：service mysqld start (5.5以上版本)

2、使用 service 启动：service mysql start
二、停止
1、使用 service 启动：service mysqld stop (5.5以上版本)

2、使用 service 启动：service mysql stop
三、重启
1、使用 service 启动：service mysqld restart (5.5以上版本)

2、使用 service 启动：service mysql restart

三、查看状态
1、使用 service 启动：service mysql status