7.8. mysqlbinlogUtility 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 4.12.3, "The Binary Log," and Section 5.4.4, "Replication Relay and Status Files."
mysqlbinlog supports the following options:
--help, -? Display a help message and exit. --character-sets-dir=path The directory where character sets are installed. See Section 4.11.1, "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 5.0.16. --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 4.9.6, "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. --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 4.10.2, "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:
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 4.10.1, "Database Backups"). For example:
shell> mysqlbinlog binlog.000001 | mysql
Or:
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 4.7.4, "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*/;
/*!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.
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 the 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.
 |
