Activating the Binary Log

Instructions for enabling the binary log using the `--log-bin` option and configuring the log file basename and index file.

To enable binary logging, start the server with the [--log-bin [=name](../../../server-usage/replication-cluster-multi-master/standard-replication/replication-and-binary-log-system-variables.md)] option.

If you specify a filename with an extension (for example .log), the extension will be silently ignored.

If you don't provide a name (which can, optionally, include an absolute path), the default is datadir/log-basename-bin, datadir/mysql-bin or datadir/mariadb-bin (the latter two if --log-basename is not specified, and dependent on server version). Datadir is determined by the value of the datadir system variable.

We strongly recommend you use either --log-basename or specify a filename to ensure that replication doesn't stop if the hostname of the computer changes.

The directory storing the binary logs contains a binary log index, as well as the individual binary log files.

The binary log files have a series of numbers as filename extensions. Each additional binary log increments the extension number, so the oldest binary logs have lower numbers, and the most recent ones have higher numbers.

A new binary log, with a new extension, is created every time the server starts, the logs are flushed, or the maximum size is reached (determined by max_binlog_size).

The binary log index file contains a master list of all the binary logs, in order. From MariaDB 11.4, if GTID binlog indexing is enabled (the default), an additional index file (.idx) is present.

A sample listing from a directory containing the binary logs:

shell> ls -l 
total 100
...
-rw-rw---- 1 mysql adm 2098 Apr 19 00:46 mariadb-bin.000079
-rw-rw---- 1 mysql adm  332 Apr 19 00:56 mariadb-bin.000080
-rw-rw---- 1 mysql adm  347 Apr 19 07:36 mariadb-bin.000081
-rw-rw---- 1 mysql adm  306 Apr 20 07:15 mariadb-bin.000082
-rw-rw---- 1 mysql adm  332 Apr 20 07:41 mariadb-bin.000083
-rw-rw---- 1 mysql adm  373 Apr 21 07:56 mariadb-bin.000084
-rw-rw---- 1 mysql adm  347 Apr 21 09:09 mariadb-bin.000085
-rw-rw---- 1 mysql adm  398 Apr 21 21:24 mariadb-bin.000086
-rw-rw---- 1 mysql adm  816 Apr 21 17:05 mariadb-bin.index

The binary log index file has, by default, the same name as the individual binary logs, with the extension .index. You can specify an alternative name with the --log-bin-index [=filename] option.

Clients with the SUPER privilege (or, from MariaDB 10.5.2, the BINLOG ADMIN privilege, can disable and re-enable the binary log for the current session by setting the sql_log_bin variable.

SET sql_log_bin = 0;

SET sql_log_bin = 1;

Binary Log Format

There are three formats for the binary log. The default is mixed logging, which is a mix of statement-based and row-based logging. See Binary Log Formats for a full discussion.

See Also

• Setting sql_log_bin

• PURGE LOGS - Delete logs

• FLUSH LOGS - Close and rotate logs

• GTID binlog indexing

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