14.4.13.1 Group Commit for Redo Log Flushing
The redo log is a disk-based data structure used during crash recovery to correct data written by incomplete transactions. During normal operations, the redo log encodes requests to change InnoDB table data that result from SQL statements or low-level API calls. Modifications that did not finish updating the data files before an unexpected shutdown are replayed automatically during initialization, and before the connections are accepted. For information about the role of the redo log in crash recovery, see Section 14.18.2, “InnoDB Recovery”.
重做日志是基于磁盘的数据结构，用来在崩溃恢复期间纠正由未完成的事务写入的数据，在正常操作期间，重做日志对更改来自SQL语句或低级API调用的InnoDB表数据的请求进行编码。。在初始化期间以及接受连接之前，会在意外关闭之前自动重播未完成更新数据文件的修改。有关重做日志在崩溃恢复中的作用的信息，请看 Section 14.18.2, “InnoDB Recovery”.
By default, the redo log is physically represented on disk as a set of files, named ib_logfile0 and ib_logfile1. MySQL writes to the redo log files in a circular fashion. Data in the redo log is encoded in terms of records affected; this data is collectively referred to as redo. The passage of data through the redo log is represented by an ever-increasing LSN value.
默认情况下，重做日志在磁盘上物理地表示为一组文件，名字为ib_logfile0 和ib_logfile1，MySQL以循环方式写入重做日志文件，重做日志中的数据按受影响的记录进行编码。这些数据统称为重做。数据通过重做日志的过程由不断增加的LSN值表示。
For related information, see:
- Section 14.6.1, “InnoDB Startup Configuration”
- Section 8.5.4, “Optimizing InnoDB Redo Logging”
- Section 14.7.2, “Changing the Number or Size of InnoDB Redo Log Files”
- InnoDB Crash Recovery
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