【MySQL学习笔记】MySQL 启动过程
下面是mysql在启动时产生的日志，在我的机器上的路径是：/data/mysqldata/3306/mysql-error.log
内容如下：
160928 15:17:19 mysqld_safe Starting mysqld daemon with databases from /data/mysqldata/3306/data 2016-09-28 15:17:30 2719 [Note] Plugin 'FEDERATED' is disabled. 2016-09-28 15:17:30 2719 [Note] InnoDB: The InnoDB memory heap is disabled 2016-09-28 15:17:30 2719 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2016-09-28 15:17:30 2719 [Note] InnoDB: Compressed tables use zlib 1.2.3 2016-09-28 15:17:30 2719 [Note] InnoDB: Using CPU crc32 instructions 2016-09-28 15:17:30 2719 [Note] InnoDB: Initializing buffer pool, size = 300.0M 2016-09-28 15:17:31 2719 [Note] InnoDB: Completed initialization of buffer pool 2016-09-28 15:17:31 2719 [Note] InnoDB: Highest supported file format is Barracuda. 2016-09-28 15:17:31 2719 [Note] InnoDB: The log sequence numbers 1626028 and 1626028 in ibdata files do not match the log sequence number 1626038 in the ib_logfiles! 2016-09-28 15:17:31 2719 [Note] InnoDB: Database was not shutdown normally! 2016-09-28 15:17:31 2719 [Note] InnoDB: Starting crash recovery. 2016-09-28 15:17:31 2719 [Note] InnoDB: Reading tablespace information from the .ibd files... 2016-09-28 15:17:31 2719 [Note] InnoDB: Restoring possible half-written data pages 2016-09-28 15:17:31 2719 [Note] InnoDB: from the doublewrite buffer... 2016-09-28 15:17:32 2719 [Note] InnoDB: 128 rollback segment(s) are active. 2016-09-28 15:17:32 2719 [Note] InnoDB: Waiting for purge to start 2016-09-28 15:17:32 2719 [Note] InnoDB: 5.6.12 started; log sequence number 1626038 2016-09-28 15:17:32 2719 [Note] Recovering after a crash using /data/mysqldata/3306/binlog/mysql-bin 2016-09-28 15:17:32 2719 [Note] Starting crash recovery... 2016-09-28 15:17:32 2719 [Note] Crash recovery finished. 2016-09-28 15:17:32 2719 [Note] Server hostname (bind-address): '*'; port: 3306 2016-09-28 15:17:32 2719 [Note] IPv6 is available. 2016-09-28 15:17:32 2719 [Note] - '::' resolves to '::'; 2016-09-28 15:17:32 2719 [Note] Server socket created on IP: '::'. 2016-09-28 15:17:33 2719 [Note] Event Scheduler: Loaded 0 events 2016-09-28 15:17:33 2719 [Note] /usr/local/mysql/bin/mysqld: ready for connections. Version: '5.6.12-log' socket: '/data/mysqldata/3306/mysql.sock' port: 3306 Source distribution
注释：
--mysqld_safe启动mysqld守护进程，数据库路径为/data/mysqldata/3306/data 160928 15:17:19 mysqld_safe Starting mysqld daemon with databases from /data/mysqldata/3306/data --federated引擎不可用，innodb内存堆不可用 2016-09-28 15:17:30 2719 [Note] Plugin 'FEDERATED' is disabled. 2016-09-28 15:17:30 2719 [Note] InnoDB: The InnoDB memory heap is disabled --互斥体和读写锁使用 gcc内建的原子锁，使用zlib 1.2.3库来压缩表，使用crc32指令 2016-09-28 15:17:30 2719 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2016-09-28 15:17:30 2719 [Note] InnoDB: Compressed tables use zlib 1.2.3 2016-09-28 15:17:30 2719 [Note] InnoDB: Using CPU crc32 instructions --初始化buffer pool，大小为300M，最高支持的文件格式为 Barracuda 2016-09-28 15:17:30 2719 [Note] InnoDB: Initializing buffer pool, size = 300.0M 2016-09-28 15:17:31 2719 [Note] InnoDB: Completed initialization of buffer pool 2016-09-28 15:17:31 2719 [Note] InnoDB: Highest supported file format is Barracuda. --日志序列号为1626028，数据文件中的日志序列号于日志文件中的 不匹配 2016-09-28 15:17:31 2719 [Note] InnoDB: The log sequence numbers 1626028 and 1626028 in ibdata files do not match the log sequence number 1626038 in the ib_logfiles! --数据库没有正常关闭，开始崩溃恢复 2016-09-28 15:17:31 2719 [Note] InnoDB: Database was not shutdown normally! 2016-09-28 15:17:31 2719 [Note] InnoDB: Starting crash recovery. --从 ibd文件中读取表空间信息。 2016-09-28 15:17:31 2719 [Note] InnoDB: Reading tablespace information from the .ibd files... --恢复可能只写了一半的数据页，这里是从双写buffer中来恢复，这个双写buffer是为了专门解决partial page write问题而设计的一个机制 2016-09-28 15:17:31 2719 [Note] InnoDB: Restoring possible half-written data pages 2016-09-28 15:17:31 2719 [Note] InnoDB: from the doublewrite buffer... --回滚段可用，等待清除开始 2016-09-28 15:17:32 2719 [Note] InnoDB: 128 rollback segment(s) are active. 2016-09-28 15:17:32 2719 [Note] InnoDB: Waiting for purge to start --innodb启动，日志序列号1626038 2016-09-28 15:17:32 2719 [Note] InnoDB: 5.6.12 started; log sequence number 1626038 --在崩溃之后，从使用binlog来恢复 2016-09-28 15:17:32 2719 [Note] Recovering after a crash using /data/mysqldata/3306/binlog/mysql-bin 2016-09-28 15:17:32 2719 [Note] Starting crash recovery... 2016-09-28 15:17:32 2719 [Note] Crash recovery finished. 2016-09-28 15:17:32 2719 [Note] Server hostname (bind-address): '*'; port: 3306 2016-09-28 15:17:32 2719 [Note] IPv6 is available. 2016-09-28 15:17:32 2719 [Note] - '::' resolves to '::'; 2016-09-28 15:17:32 2719 [Note] Server socket created on IP: '::'. 2016-09-28 15:17:33 2719 [Note] Event Scheduler: Loaded 0 events 2016-09-28 15:17:33 2719 [Note] /usr/local/mysql/bin/mysqld: ready for connections. Version: '5.6.12-log' socket: '/data/mysqldata/3306/mysql.sock' port: 3306 Source distribution
