MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6

13.4.1.1 PURGE BINARY LOGS Statement

PURGE { BINARY | MASTER } LOGS {
    TO 'log_name'
  | BEFORE datetime_expr
}

The binary log is a set of files that contain information about data modifications made by the MySQL server. The log consists of a set of binary log files, plus an index file (see Section 5.4.4, “The Binary Log”).

The PURGE BINARY LOGS statement deletes all the binary log files listed in the log index file prior to the specified log file name or date. BINARY and MASTER are synonyms. Deleted log files also are removed from the list recorded in the index file, so that the given log file becomes the first in the list.

PURGE BINARY LOGS requires the BINLOG_ADMIN privilege. This statement has no effect if the server was not started with the --log-bin option to enable binary logging.

Examples: 

PURGE BINARY LOGS TO 'mysql-bin.010';
PURGE BINARY LOGS BEFORE '2019-04-02 22:46:26';

The BEFORE variant's datetime_expr argument should evaluate to a DATETIME value (a value in 'YYYY-MM-DD hh:mm:ss' format).

This statement is safe to run while replicas are replicating. You need not stop them. If you have an active replica that currently is reading one of the log files you are trying to delete, this statement does not delete the log file that is in use or any log files later than that one, but it deletes any earlier log files. A warning message is issued in this situation. However, if a replica is not connected and you happen to purge one of the log files it has yet to read, the replica cannot replicate after it reconnects.

To safely purge binary log files, follow this procedure:

  1. On each replica, use SHOW SLAVE STATUS to check which log file it is reading.

  2. Obtain a listing of the binary log files on the replication source server with SHOW BINARY LOGS.

  3. Determine the earliest log file among all the replicas. This is the target file. If all the replicas are up to date, this is the last log file on the list.

  4. Make a backup of all the log files you are about to delete. (This step is optional, but always advisable.)

  5. Purge all log files up to but not including the target file.

You can also set the expire_logs_days system variable to expire binary log files automatically after a given number of days (see Section 5.1.7, “Server System Variables”). If you are using replication, you should set the variable no lower than the maximum number of days your replicas might lag behind the source.

PURGE BINARY LOGS TO and PURGE BINARY LOGS BEFORE both fail with an error when binary log files listed in the .index file had been removed from the system by some other means (such as using rm on Linux). (Bug #18199, Bug #18453) To handle such errors, edit the .index file (which is a simple text file) manually to ensure that it lists only the binary log files that are actually present, then run again the PURGE BINARY LOGS statement that failed.

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