Using mysqlbinlog

The MariaDB server's binary log is a set of files containing "events" which represent modifications to the contents of a MariaDB database. These events are written in a binary (i.e. non-human-readable) format. The mysqlbinlog utility is used to view these events in plain text.

Run mysqlbinlog from a command-line like this:

shell> mysqlbinlog [options] log_file ...

See mysqlbinlog Options for details on the available options.

As an example, here is how you could display the contents of a binary log file named "mariadb-bin.000152":

shell> mysqlbinlog mariadb-bin.000152

If you are using statement-based logging (the default) the output includes the SQL statement, the ID of the server the statement was executed on, a timestamp, and how much time the statement took to execute. If you are using row-based logging the output of an event will not include an SQL statement but will instead output how individual rows were changed.

The output from mysqlbinlog can be used as input to the mysql client to redo the statements contained in a binary log. This is useful for recovering after a server crash. Here is an example:

shell> mysqlbinlog binlog-filenames | mysql -u root -p

If you would like to view and possibly edit the file before applying it to your database, use the '-r' flag to redirect the output to a file:

shell> mysqlbinlog -r filename binlog-filenames

You can then open the file and view it and delete any statements you don't want executed (such as an accidental DROP DATABASE). Once you are satisfied with the contents you can execute it with:

shell> mysql -u root -p < filename

Be careful to process multiple log files in a single connection, especially if one or more of them have any CREATE TEMPORARY TABLE ... statements. Temporary tables are dropped when the mysql client terminates, so if you are processing multiple log files one at a time (i.e. multiple connections) and one log file creates a temporary table and then a subsequent log file refers to the table you will get an 'unknown table' error.

To execute multiple logfiles using a single connection, list them all on the mysqlbinlog command line:

shell> mysqlbinlog mariadb-bin.000001 mariadb-bin.000002 | mysql -u root -p

If you need to manually edit the binlogs before executing them, combine them all into a single file before processing. Here is an example:

shell> mysqlbinlog mariadb-bin.000001 > /tmp/mariadb-bin.sql
shell> mysqlbinlog mariadb-bin.000002 >> /tmp/mariadb-bin.sql
shell> # make any edits
shell> mysql -u root -p -e "source /tmp/mariadb-bin.sql"

See Also

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