Using and Maintaining the Binary Log
Complete binary log maintenance: PURGE BINARY LOGS/RESET MASTER, expire_logs_days & binlog_expire_logs_seconds, FLUSH BINARY LOGS, and SHOW SLAVE STATUS.
See Overview of the Binary Log for a general overview of what the binary log is and Activating the Binary Log for how to make sure it's running on your system.
For details on using the binary log for replication, see the Replication section.
Purging Log Files
To delete all binary logs on the server, run the RESET MASTER command. To delete all binary logs before a certain datetime, or up to a certain number, use PURGE BINARY LOGS.
If a replica is active but has yet to read from a binary log you attempt to delete, the statement fails with an error. However, if the replica is not connected and has yet to read from a log you delete, the file is deleted, but the replica is unable to continue replicating once it connects again.
Logs can also be removed automatically with the expire_logs_days system variable. This is set to 0 by default (no removal). It can be set to a time, in days, after which a binary log file is automatically removed. Log files are only checked for being older than expire_logs_days upon log rotation, so if your binary log fills up slowly and does not reach max_binlog_size on a daily basis, you may see older logs still being kept. You can also force log rotation, and so expiry deletes, by running FLUSH BINARY LOGS on a regular basis. Always set expire_logs_days higher than any possible replica lag.
From MariaDB 10.6, the binlog_expire_logs_seconds variable allows more precise control over binlog deletion and takes precedence if both are non-zero.
From MariaDB 12.3, InnoDB-based binary logs can be used. (This is configurable, and not the default.)
If configured, binary logs are stored in InnoDB tablespaces, rather than binary files. This removes the need of protecting binary logs separately, since they'll "inherit" the same protection as other MariaDB database tables. Also, any other information about log files doesn't apply – for example, you cannot specify a storage location for binary logs stored in an InnoDB tablespace.
InnoDB-based binary logs are enabled by setting binlog_storage_engine=innodb in the server configuration. See InnoDB-Based Binary Log for more information.
If the binary log index file has been removed, or incorrectly manually edited, all of the above forms of purging logs fail. The .index file is a plain text file and can be manually recreated or edited so that it lists only the binary log files that are present, in numeric/age order.
Examples of Log File Purging
PURGE BINARY LOGS TO 'mariadb-bin.000063';PURGE BINARY LOGS BEFORE '2013-04-22 09:55:22';Safely Purging Binary Log Files While Replicating
To be sure replication is not broken while deleting log files, perform the following steps:
Get a listing of binary log files on the primary by running SHOW BINARY LOGS.
Go to each replica server and run SHOW REPLICA STATUS to check which binary log file each replica is currently reading.
Find the earliest log file still being read by a replica. No log files before this one will be needed.
If you wish, make a backup of the log files to be deleted
Purge all log files before (not including) the file identified above.
Limiting the Binlog Size
This feature is available from MariaDB 11.4.
You can limit the size of the binlog by setting the max_binlog_total_size system variable. If not set to zero, the total size of the binlog is stored in the binlog_disk_use status variable. It's also possible to limit the size of a single binlog file by setting max_binlog_size.
Selectively Logging to the Binary Log
By default, all changes to data or data structure are logged. This behavior can be changed by starting the server with the --binlog-ignore-db=database_name or --binlog-do-db=database_name options.
--binlog-ignore-db=database_name specified a database to ignore for logging purposes, while --binlog-do-db=database_name will not log any statements unless they apply to the specified database.
Neither option accepts comma-delimited lists of multiple databases as an option, since a database name can contain a comma. To apply to multiple databases, use the option multiple times.
--binlog-ignore-db=database_name behaves differently depending on whether statement-based or row-based logging is used. For statement-based logging, the server will not log any statement where the default database is database_name. The default database is set with the USE statement.
Similarly, --binlog-do-db=database_name also behaves differently depending on whether statement-based or row-based logging is used.
For statement-based logging, the server will only log statement where the default database is database_name. The default database is set with the USE statement.
For row-based logging, the server will log any updates to any tables in the named database/s, irrespective of the current database.
Examples of Selective Logging
Assume the server has started with the option --binlog-ignore-db=employees. The following example is logged if statement-based logging is used, and is not logged with row-based logging.
This is because statement-based logging examines the default database, in this case, customers. Since customers is not specified in the ignore list, the statement is logged. If row-based logging is used, the example is not logged, because updates are written to the tables in the employees database.
Assume now that the server started with the option --binlog-do-db=employees. The following example is not logged if statement-based logging is used, and is logged with row-based logging.
This is again because statement-based logging examines the default database, in this case, customers. Since customers is not specified in the do list, the statement is not logged. If row-based logging is used, the example is logged as updates are written to the tables in the employees database.
Effects of Full Disk Errors on Binary Logging
From MariaDB 12.3, InnoDB-based binary logs can be used. (This is configurable, and not the default.)
If configured, binary logs are stored in InnoDB tablespaces, rather than binary files. This removes the need of protecting binary logs separately, since they'll "inherit" the same protection as other MariaDB database tables. Also, any other information about log files doesn't apply – for example, you cannot specify a storage location for binary logs stored in an InnoDB tablespace.
InnoDB-based binary logs are enabled by setting binlog_storage_engine=innodb in the server configuration. See InnoDB-Based Binary Log for more information.
If MariaDB encounters a full disk error while trying to write to a binary log file, then it will keep retrying the write every 60 seconds. Log messages will get written to the error log every 600 seconds. For example:
However, if MariaDB encounters a full disk error while trying to open a new binary log file, then it will disable binary logging entirely. A log message like the following will be written to the error log:
See Also
This page is licensed: CC BY-SA / Gnu FDL
Last updated
Was this helpful?