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8.8. 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.

Invoke mysqlbinlog like this:

shell> mysqlbinlog [options] log_file ...

For example, to display the contents of the binary log file named binlog.000003, use this command:

shell> mysqlbinlog binlog.0000003

The output includes all events contained in binlog.000003. 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 --read-from-remote-server 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 --host, --password, --port, --protocol, --socket, and --user; they are ignored except when you also use the --read-from-remote-server option.

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.

Binary logs and relay logs are discussed further in Section 5.11.4, “The Binary Log”, and Section 6.4.4, “Replication Relay and Status Files”. further.

mysqlbinlog supports the following options:

  • --help, -?

    Display a help message and exit.

  • --base64-output

    Print all binary log entries using base64 encoding. This is for debugging only. Logs produced using this option should not be applied on production systems. This option was added in MySQL 5.1.5.

  • --character-sets-dir=path

    The directory where character sets are installed. See Section 5.10.1, “The Character Set Used for Data and Sorting”.

  • --database=db_name, -d db_name

    List entries for just this database (local log only).

  • --debug[=debug_options], -# [debug_options]

    Write a debugging log. A typical debug_options string is often 'd:t:o,file_name'.

  • --disable-log-bin, -D

    Disable binary logging. This is useful for avoiding an endless loop if you use the --to-last-log 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 SUPER privilege. It causes mysqlbinlog to include a SET SQL_LOG_BIN=0 statement in its output to disable binary logging of the remaining output. The SET statement is ineffective unless you have the SUPER privilege.

  • --force-read, -f

    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.

  • --hexdump, -H

    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 5.1.2.

  • --host=host_name, -h host_name

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

  • --local-load=path, -l path

    Prepare local temporary files for LOAD DATA INFILE in the specified directory.

  • --offset=N, -o N

    Skip the first N entries in the log.

  • --password[=password], -p[password]

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

    Specifying a password on the command line should be considered insecure. See Section 5.8.6, “Keeping Your Password Secure”.

  • --port=port_num, -P port_num

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

  • --position=N, -j N

    Deprecated. Use --start-position instead.

  • --protocol={TCP|SOCKET|PIPE|MEMORY}

    The connection protocol to use.

  • --read-from-remote-server, -R

    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 --host, --password, --port, --protocol, --socket, and --user.

  • --result-file=name, -r name

    Direct output to the given file.

  • --server-id=id

    Extract only those events created by the server having the given server ID. This option is available as of MySQL 5.1.4.

  • --short-form, -s

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

  • --socket=path, -S path

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

  • --start-datetime=datetime

    Start reading the binary log at the first event having a timestamp equal to or later than the datetime argument. The datetime 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 DATETIME or TIMESTAMP data types. For example:

    shell> mysqlbinlog --start-datetime="2005-12-25 11:25:56" binlog.000003

    This option is useful for point-in-time recovery. See Section 5.9.2, “Example Backup and Recovery Strategy”.

  • --stop-datetime=datetime

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

  • --start-position=N

    Start reading the binary log at the first event having a position equal to the N argument.

  • --stop-position=N

    Stop reading the binary log at the first event having a position equal or greater than the N argument.

  • --to-last-log, -t

    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 --read-from-remote-server.

  • --user=user_name, -u user_name

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

  • --version, -V

    Display version information and exit.

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

  • open_files_limit

    Specify the number of open file descriptors to reserve.

It is also possible to set variables by using --set-variable=var_name=value or -O var_name=value 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 5.9.1, “Database Backups”). For example:

shell> mysqlbinlog binlog.000001 | mysql


shell> mysqlbinlog binlog.[0-9]* | mysql

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 --start-position 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 --stop-datetime 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> mysqlbinlog binlog.000001 | mysql # DANGER!!
shell> mysqlbinlog binlog.000002 | mysql # DANGER!!

Processing binary logs this way using different connections to the server causes problems if the first log file contains a CREATE TEMPORARY TABLE 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> mysqlbinlog binlog.000001 binlog.000002 | mysql

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

shell> mysqlbinlog binlog.000001 >  /tmp/statements.sql
shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql
shell> mysql -e "source /tmp/statements.sql"

mysqlbinlog can produce output that reproduces a LOAD DATA INFILE operation without the original data file. mysqlbinlog copies the data to a temporary file and writes a LOAD DATA LOCAL INFILE 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 --local-load option.

Because mysqlbinlog converts LOAD DATA INFILE statements to LOAD DATA LOCAL INFILE statements (that is, it adds LOCAL), both the client and the server that you use to process the statements must be configured to allow LOCAL capability. See Section 5.6.4, “Security Issues with LOAD DATA LOCAL.

Warning: The temporary files created for LOAD DATA LOCAL 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 original_file_name-#-#.

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

shell> mysqlbinlog --hexdump master-bin.000001

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

/*!40019 SET @@session.max_insert_delayed_threads=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

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

  • Position: The byte position within the log file.

  • Timestamp: The event timestamp. In the example shown, '9d fc 5c 43' is the representation of '051024 17:24:13' in hexadecimal.

  • Type: The type of the log event. In the example shown, '0f' means that the example event is a FORMAT_DESCRIPTION_EVENT. The following table lists the possible types.

    Type Name Meaning
    00 UNKNOWN_EVENT This event should never be present in the log.
    01 START_EVENT_V3 This indicates the start of a log file written by MySQL 4 or earlier.
    02 QUERY_EVENT The most common type of events. These contain statements executed on the master.
    03 STOP_EVENT Indicates that master has stopped.
    04 ROTATE_EVENT Written when the master switches to a new log file.
    05 INTVAR_EVENT Used mainly for AUTO_INCREMENT values and when the LAST_INSERT_ID() function is used in the statement.
    06 LOAD_EVENT Used for LOAD DATA INFILE in MySQL 3.23.
    07 SLAVE_EVENT Reserved for future use.
    08 CREATE_FILE_EVENT Used for LOAD DATA INFILE statements. This indicates the start of execution of such a statement. A temporary file is created on the slave. Used in MySQL 4 only.
    09 APPEND_BLOCK_EVENT Contains data for use in a LOAD DATA INFILE statement. The data is stored in the temporary file on the slave.
    0a EXEC_LOAD_EVENT Used for LOAD DATA INFILE statements. The contents of the temporary file is stored in the table on the slave. Used in MySQL 4 only.
    0b DELETE_FILE_EVENT Rollback of a LOAD DATA INFILE statement. The temporary file should be deleted on slave.
    0c NEW_LOAD_EVENT Used for LOAD DATA INFILE in MySQL 4 and earlier.
    0d RAND_EVENT Used to send information about random values if the RAND() function is used in the statement.
    0e USER_VAR_EVENT Used to replicate user variables.
    0f FORMAT_DESCRIPTION_EVENT This indicates the start of a log file written by MySQL 5 or later.
    10 XID_EVENT Event indicating commit of an XA transaction.
    11 BEGIN_LOAD_QUERY_EVENT Used for LOAD DATA INFILE statements in MySQL 5 and later.
    12 EXECUTE_LOAD_QUERY_EVENT Used for LOAD DATA INFILE statements in MySQL 5 and later.
    13 TABLE_MAP_EVENT Reserved for future use.
    14 WRITE_ROWS_EVENT Reserved for future use.
    15 UPDATE_ROWS_EVENT Reserved for future use.
    16 DELETE_ROWS_EVENT Reserved for future use.
  • Master ID: The server id of the master that created the event.

  • Size: The size in bytes of the event.

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

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

    Flag Name Meaning
    01 LOG_EVENT_BINLOG_IN_USE_F Log file correctly closed. (Used only in FORMAT_DESCRIPTION_EVENT.) If this flag is set (if the flags are, for example, '01 00') in a FORMAT_DESCRIPTION_EVENT, the log file has not been properly closed. Most probably this is because of a master crash (for example, due to power failure).
    02   Reserved for future use.
    04 LOG_EVENT_THREAD_SPECIFIC_F Set if the event is dependent on the connection it was executed in (for example, '04 00'), for example, if the event uses temporary tables.
    08 LOG_EVENT_SUPPRESS_USE_F Set in some circumstances when the event is not dependent on the default database.

    The other flags are reserved for future use.

  Published under the terms of the GNU General Public License Design by Interspire