# Using mariadb-binlog

{% hint style="info" %}
Previously, the client was called `mysqlbinlog`. It can still be accessed under this name, via a symlink in Linux, or an alternate binary in Windows.
{% endhint %}

## Overview

The MariaDB server's [binary log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/binary-log) is a set of files containing "events" which represent modifications to the contents of a MariaDB database.

Events are written in a binary (that is, non-human-readable) format. The `mariadb-binlog` utility is used to view these events in plain text.

Run [mariadb-binlog](https://mariadb.com/docs/server/clients-and-utilities/logging-tools/mariadb-binlog) from a command line:

```bash
mariadb-binlog [options] binlog-filename [binlog-filename ...]
```

See [mariadb-binlog Options](https://mariadb.com/docs/server/clients-and-utilities/logging-tools/mariadb-binlog/mariadb-binlog-options) for details on the available options.

## Usage

Display the contents of a [binary log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/binary-log) file named `mariadb-bin.000152` like this:

```bash
mariadb-binlog mariadb-bin.000152
```

### Processing a Single Log File

The logging format is determined by the value of the [binlog\_format](https://mariadb.com/docs/server/ha-and-performance/standard-replication/replication-and-binary-log-system-variables#binlog_format) system variable. If you are using statement-based logging, 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 `mariadb-binlog` can be used as input to the `mariadb` client to redo the statements contained in a [binary log](https://mariadb.com/docs/server/server-management/server-monitoring-logs/binary-log). This is useful for recovering after a server crash (replace *binlog-filename* with the name of a binary log file):

```bash
mariadb-binlog binlog-filename | 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 (replace *outputfile* with the name of a file to store the output, and *binlog-filename* with the name of a binary log file):

```bash
mariadb-binlog -r outputfile binlog-filename
```

In the output file, 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:

```bash
mariadb -u root -p --binary-mode < outputfilename
```

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 mariadb 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 get an 'unknown table' error.

### Processing Multiple Log Files

To execute multiple log files using a single connection, list them all on the `mariadb-binlog` command line:

```bash
mariadb-binlog mariadb-bin.000001 mariadb-bin.000002 | mariadb -u root -p --binary-mode
```

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

```bash
mariadb-binlog mariadb-bin.000001 > /tmp/mariadb-bin.sql
mariadb-binlog mariadb-bin.000002 >> /tmp/mariadb-bin.sql
# make any edits
mariadb -u root -p -e "source /tmp/mariadb-bin.sql"
```

## See Also

* [mariadb-binlog](https://mariadb.com/docs/server/clients-and-utilities/logging-tools/mariadb-binlog)
* [mariadb-binlog Options](https://mariadb.com/docs/server/clients-and-utilities/logging-tools/mariadb-binlog/mariadb-binlog-options)

<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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