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https://dev.mysql.com/doc/refman/5.7/en/innodb-redo-log.html
https://dev.mysql.com/doc/refman/5.7/en/mysqlbinlog.html
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 15.18.2, “InnoDB Recovery”.
The server's binary log consists of files containing “events” that describe modifications to database contents. The server writes these files in binary format. To display their contents in text format, use the mysqlbinlog utility. You can also use mysqlbinlog to display the contents of relay log files written by a slave server in a replication setup because relay logs have the same format as binary logs. The binary log and relay log are discussed further in Section 6.4.4, “The Binary Log”, and Section 17.2.4, “Replication Relay and Status Logs”.