8.10. mysqlbinlog — Utility for Processing Binary Log Files

MySQL 5.0

8.10. mysqlbinlog — Utility for Processing Binary Log Files

The binary log files that the server generates are written in binary format. To examine these files in text format, use the mysqlbinlog utility. You can also use mysqlbinlog to read relay log files written by a slave server in a replication setup. Relay logs have the same format as binary log files.

Invoke mysqlbinlog like this:

shell> ]  ...

For example, to display the contents of the binary log file named , use this command:

shell> 

The output includes all events contained in . Event information includes the statement executed, the time the statement took, the thread ID of the client that issued it, the timestamp when it was executed, and so forth.

The output from mysqlbinlog can be re-executed (for example, by using it as input to mysql) to reapply the statements in the log. This is useful for recovery operations after a server crash. For other usage examples, see the discussion later in this section.

Normally, you use mysqlbinlog to read binary log files directly and apply them to the local MySQL server. It is also possible to read binary logs from a remote server by using the option. When you read remote binary logs, the connection parameter options can be given to indicate how to connect to the server. These options are , , , , , and ; they are ignored except when you also use the option.

Binary logs and relay logs are discussed further in Section 5.12.3, “The Binary Log”, and Section 6.3.4, “Replication Relay and Status Files”.

mysqlbinlog supports the following options:

  • ,

    Display a help message and exit.

  • The directory where character sets are installed. See Section 5.11.1, “The Character Set Used for Data and Sorting”.

  • ,

    List entries for just this database (local log only). You can only specify one database with this option - if you specify multiple options, only the last one is used. This option forces mysqlbinlog to output entries from the binary log where the default database (that is, the one selected by ) is . Note that this does not replicate cross-database statements such as SET foo='bar' while having selected a different database or no database.

  • ], ]

    Write a debugging log. A typical string is often '.

  • ,

    Disable binary logging. This is useful for avoiding an endless loop if you use the option and are sending the output to the same MySQL server. This option also is useful when restoring after a crash to avoid duplication of the statements you have logged.

    This option requires that you have the privilege. It causes mysqlbinlog to include a statement in its output to disable binary logging of the remaining output. The statement is ineffective unless you have the privilege.

  • ,

    With this option, if mysqlbinlog reads a binary log event that it does not recognize, it prints a warning, ignores the event, and continues. Without this option, mysqlbinlog stops if it reads such an event.

  • ,

    Display a hex dump of the log in comments. This output can be helpful for replication debugging. Hex dump format is discussed later in this section. This option was added in MySQL 5.0.16.

  • ,

    Get the binary log from the MySQL server on the given host.

  • ,

    Prepare local temporary files for in the specified directory.

  • ,

    Skip the first entries in the log.

  • ], ]

    The password to use when connecting to the server. If you use the short option form (), you cannot have a space between the option and the password. If you omit the value following the or option on the command line, you are prompted for one.

    Specifying a password on the command line should be considered insecure. See Section 5.9.6, “Keeping Your Password Secure”.

  • ,

    The TCP/IP port number to use for connecting to a remote server.

  • ,

    Deprecated. Use instead.

  • The connection protocol to use.

  • ,

    Read the binary log from a MySQL server rather than reading a local log file. Any connection parameter options are ignored unless this option is given as well. These options are , , , , , and .

  • ,

    Direct output to the given file.

  • Add a statement to the output to specify the character set to be used for processing log files. This option was added in MySQL 5.0.23.

  • ,

    Display only the statements contained in the log, without any extra information.

  • ,

    For connections to , the Unix socket file to use, or, on Windows, the name of the named pipe to use.

  • Start reading the binary log at the first event having a timestamp equal to or later than the argument. The value is relative to the local time zone on the machine where you run mysqlbinlog. The value should be in a format accepted for the or data types. For example:

    shell> 
    

    This option is useful for point-in-time recovery. See Section 5.10.2, “Example Backup and Recovery Strategy”.

  • Stop reading the binary log at the first event having a timestamp equal or posterior to the argument. This option is useful for point-in-time recovery. See the description of the option for information about the value.

  • Start reading the binary log at the first event having a position equal to the argument. This option applies to the first log file named on the command line.

  • Stop reading the binary log at the first event having a position equal or greater than the argument. This option applies to the last log file named on the command line.

  • ,

    Do not stop at the end of the requested binary log from a MySQL server, but rather continue printing until the end of the last binary log. If you send the output to the same MySQL server, this may lead to an endless loop. This option requires .

  • ,

    The MySQL username to use when connecting to a remote server.

  • ,

    Display version information and exit.

You can also set the following variable by using = syntax:

  • Specify the number of open file descriptors to reserve.

It is also possible to set variables by using = or = syntax. This syntax is deprecated.

You can pipe the output of mysqlbinlog into the mysql client to execute the statements contained in the binary log. This is used to recover from a crash when you have an old backup (see Section 5.10.1, “Database Backups”). For example:

shell> 

Or:

shell> 

You can also redirect the output of mysqlbinlog to a text file instead, if you need to modify the statement log first (for example, to remove statements that you do not want to execute for some reason). After editing the file, execute the statements that it contains by using it as input to the mysql program.

mysqlbinlog has the option, which prints only those statements with an offset in the binary log greater than or equal to a given position (the given position must match the start of one event). It also has options to stop and start when it sees an event with a given date and time. This enables you to perform point-in-time recovery using the option (to be able to say, for example, “roll forward my databases to how they were today at 10:30 a.m.”).

If you have more than one binary log to execute on the MySQL server, the safe method is to process them all using a single connection to the server. Here is an example that demonstrates what may be unsafe:

shell> 
shell> 

Processing binary logs this way using different connections to the server causes problems if the first log file contains a statement and the second log contains a statement that uses the temporary table. When the first mysql process terminates, the server drops the temporary table. When the second mysql process attempts to use the table, the server reports “unknown table.

To avoid problems like this, use a single connection to execute the contents of all binary logs that you want to process. Here is one way to do so:

shell> 

Another approach is to write all the logs to a single file and then process the file:

shell> 
shell> 
shell> 

mysqlbinlog can produce output that reproduces a operation without the original data file. mysqlbinlog copies the data to a temporary file and writes a statement that refers to the file. The default location of the directory where these files are written is system-specific. To specify a directory explicitly, use the option.

Because mysqlbinlog converts statements to statements (that is, it adds ), both the client and the server that you use to process the statements must be configured to allow capability. See Section 5.7.4, “Security Issues with .

Warning: The temporary files created for statements are not automatically deleted because they are needed until you actually execute those statements. You should delete the temporary files yourself after you no longer need the statement log. The files can be found in the temporary file directory and have names like .

The option produces a hex dump of the log contents in comments:

shell> 

With the preceding command, the output might look like this:

/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
# at 4
#051024 17:24:13 server id 1  end_log_pos 98
# Position  Timestamp   Type   Master ID        Size      Master Pos    Flags
# 00000004 9d fc 5c 43   0f   01 00 00 00   5e 00 00 00   62 00 00 00   00 00
# 00000017 04 00 35 2e 30 2e 31 35  2d 64 65 62 75 67 2d 6c |..5.0.15.debug.l|
# 00000027 6f 67 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |og..............|
# 00000037 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |................|
# 00000047 00 00 00 00 9d fc 5c 43  13 38 0d 00 08 00 12 00 |.......C.8......|
# 00000057 04 04 04 04 12 00 00 4b  00 04 1a                |.......K...|
#       Start: binlog v 4, server v 5.0.15-debug-log created 051024 17:24:13
#       at startup
ROLLBACK;

Hex dump output currently contains the following elements. This format might change in the future.

  • : The byte position within the log file.

  • : The event timestamp. In the example shown, is the representation of in hexadecimal.

  • : The type of the log event. In the example shown, means that the example event is a . The following table lists the possible types.

    Type Name Meaning
    This event should never be present in the log.
    This indicates the start of a log file written by MySQL 4 or earlier.
    The most common type of events. These contain statements executed on the master.
    Indicates that master has stopped.
    Written when the master switches to a new log file.
    Used mainly for values and when the function is used in the statement.
    Used for in MySQL 3.23.
    Reserved for future use.
    Used for statements. This indicates the start of execution of such a statement. A temporary file is created on the slave. Used in MySQL 4 only.
    Contains data for use in a statement. The data is stored in the temporary file on the slave.
    Used for statements. The contents of the temporary file is stored in the table on the slave. Used in MySQL 4 only.
    Rollback of a statement. The temporary file should be deleted on slave.
    Used for in MySQL 4 and earlier.
    Used to send information about random values if the function is used in the statement.
    Used to replicate user variables.
    This indicates the start of a log file written by MySQL 5 or later.
    Event indicating commit of an XA transaction.
    Used for statements in MySQL 5 and later.
    Used for statements in MySQL 5 and later.
    Reserved for future use.
    Reserved for future use.
    Reserved for future use.
    Reserved for future use.
  • : The server id of the master that created the event.

  • : The size in bytes of the event.

  • : The position of the event in the original master log file.

  • : 16 flags. Currently, the following flags are used. The others are reserved for the future.

    Flag Name Meaning
    Log file correctly closed. (Used only in .) If this flag is set (if the flags are, for example, ) in a , the log file has not been properly closed. Most probably this is because of a master crash (for example, due to power failure).
      Reserved for future use.
    Set if the event is dependent on the connection it was executed in (for example, ), for example, if the event uses temporary tables.
    Set in some circumstances when the event is not dependent on the default database.

    The other flags are reserved for future use.