Mysql – Can you restore purged MySQL binary logs

Use the mysqlbinlog utility

mysqlbinlog --help gives the following:

-j, --start-position=#
                  Start reading the binlog at position N. Applies to the
                  first binlog passed on the command line.
--stop-position=#   Stop reading the binlog at position N. Applies to the
                  last binlog passed on the command line.

Suppose your binary log is called mysql-bin.012345. You would do the following for positions 10 - 2500 to attach it to a mysqldump called MySQLData.sql:

Either

mysqlbinlog --start-position=10 --stop-position=2500 mysql-bin.012345 > SQLFromBinLog.sql
cat SQLFromBinLog.sql >> MySQLData.sql

or append directly with

mysqlbinlog --start-position=10 --stop-position=2500 mysql-bin.012345 >> MySQLData.sql

Give it a Try !!!

The number in the mysql-bin.nnnnnn filename is simply a sequence number. This gets updated every time a FLUSH LOGS is initiated, either manually or through predetermined means and is sequential (e.g. normally starts at 00001 and goes up).

The logs will be kept forever unless you specify an expiry. This should be done in your MySQL configuration:

http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_expire_logs_days

You can also delete the binary logs manually within MySQL by using the command:

PURGE BINARY LOGS .... [TO FILENAME | BEFORE 'DATE' ]

See details here http://dev.mysql.com/doc/refman/5.6/en/purge-binary-logs.html

It is possible to delete the files manually (outside of MySQL) but NOT recommended.

See http://dev.mysql.com/doc/refman/5.6/en/binary-log.html for details on the binary logging system.