4.6.8. mysqlbinlog — Utility for Processing Binary Log Files

4.6.8.1. mysqlbinlog Hex Dump Format
4.6.8.2. mysqlbinlog Row Event Display
4.6.8.3. Using mysqlbinlog to Back Up Binary Log Files
4.6.8.4. Specifying the mysqlbinlog Server ID

The server's binary log consists of files containing "events" that describe modifications to database contents. The server writes these files in binary format. To display their contents in text format, use the mysqlbinlog utility. You can also use mysqlbinlog to display the contents of relay log files written by a slave server in a replication setup because relay logs have the same format as binary logs. The binary log and relay log are discussed further in Section 5.2.4, "The Binary Log", and Section 16.2.2, "Replication Relay and Status Logs".

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 events contained in binlog.000003. For statement-based logging, event information includes the SQL statement, the ID of the server on which it was executed, the timestamp when the statement was executed, how much time it took, and so forth. For row-based logging, the event indicates a row change rather than an SQL statement. See Section 16.1.2, "Replication Formats", for information about logging modes.

Events are preceded by header comments that provide additional information. For example:

# at 141#100309  9:28:36 server id 123  end_log_pos 245  Query thread_id=3350  exec_time=11  error_code=0

In the first line, the number following at indicates the starting position of the event in the binary log file.

The second line starts with a date and time indicating when the statement started on the server where the event originated. For replication, this timestamp is propagated to slave servers. server id is the server_id value of the server where the event originated. end_log_pos indicates where the next event starts (that is, it is the end position of the current event + 1). thread_id indicates which thread executed the event. exec_time is the time spent executing the event, on a master server. On a slave, it is the difference of the end execution time on the slave minus the beginning execution time on the master. The difference serves as an indicator of how much replication lags behind the master. error_code indicates the result from executing the event. Zero means that no error occurred.

The output from mysqlbinlog can be re-executed (for example, by using it as input to mysql) to redo 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 and in Section 7.5, "Point-in-Time (Incremental) Recovery Using the Binary Log".

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. To 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.

mysqlbinlog supports the following options, which can be specified on the command line or in the [mysqlbinlog] and [client] groups of an option file. mysqlbinlog also supports the options for processing option files described at Section 4.2.3.4, "Command-Line Options that Affect Option-File Handling".

Table 4.14. mysqlbinlog Options

Format Option File Description Introduced
--base64-output=value base64-output Print binary log entries using base-64 encoding
--bind-address=ip_address bind-address Use the specified network interface to connect to the MySQL Server
--binlog-row-event-max-size=# binlog-row-event-max-size Binary log max event size
--character-sets-dir=path character-sets-dir The directory where character sets are installed
--database=db_name database List entries for just this database
--debug[=debug_options] debug Write a debugging log
--debug-check debug-check Print debugging information when the program exits
--debug-info debug-info Print debugging information, memory and CPU statistics when the program exits
--default-auth=plugin default-auth=plugin The authentication plugin to use
--disable-log-bin disable-log-bin Disable binary logging
--exclude-gtids=gtid_set exclude-gtids Do not show any of the groups in the GTID set provided
--force-if-open force-if-open Read binary log files even if open or not closed properly
--force-read force-read If mysqlbinlog reads a binary log event that it does not recognize, it prints a warning
--help Display help message and exit
--hexdump hexdump Display a hex dump of the log in comments
--host=host_name host Connect to the MySQL server on the given host
--idempotent idempotent Cause the server to use idempotent mode while processing binary log updates from this session only 5.7.0
--include-gtids=gtid_set include-gtids Show only the groups in the GTID set provided
--local-load=path local-load Prepare local temporary files for LOAD DATA INFILE in the specified directory
--login-path=name Read login path options from .mylogin.cnf
--offset=# offset Skip the first N entries in the log
--password[=password] password The password to use when connecting to the server
--plugin-dir=path plugin-dir=path The directory where plugins are located
--port=port_num port The TCP/IP port number to use for the connection
--protocol=type protocol The connection protocol to use
--raw raw Write events in raw (binary) format to output files
--read-from-remote-master=type read-from-remote-master Read the binary log from a MySQL master rather than reading a local log file
--read-from-remote-server read-from-remote-server Read binary log from MySQL server rather than local log file
--result-file=name result-file Direct output to the given file
--rewrite-db='oldname->newname' rewrite-db Create rewrite rules for databases when playing back from logs written in row-based format. Can be used multiple times. 5.7.1
--server-id=id server-id Extract only those events created by the server having the given server ID
--set-charset=charset_name set-charset Add a SET NAMES charset_name statement to the output
--short-form short-form Display only the statements contained in the log
--skip-gtids[=true|false] skip-gtids Do not show any GTIDs; not recommended in production
--socket=path socket For connections to localhost
--start-datetime=datetime start-datetime Read binary log from first event with timestamp equal to or later than datetime argument
--start-position=# start-position Read binary log from first event with position equal to or greater than argument
--stop-datetime=datetime stop-datetime Stop reading binary log at first event with timestamp equal to or greater than datetime argument
--stop-never stop-never Stay connected to server after reading last binary log file
--stop-never-slave-server-id=# stop-never-slave-server-id Slave server ID to report when connecting to server
--stop-position=# stop-position Stop reading binary log at first event with position equal to or greater than argument
--to-last-log to-last-log Do not stop at the end of requested binary log from a MySQL server, but rather continue printing to end of last binary log
--user=user_name, user MySQL user name to use when connecting to server
--verbose Reconstruct row events as SQL statements
--verify-binlog-checksum Verify checksums in binary log
--version Display version information and exit

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

You can pipe the output of mysqlbinlog into the mysql client to execute the events contained in the binary log. This technique is used to recover from a crash when you have an old backup (see Section 7.5, "Point-in-Time (Incremental) Recovery Using the Binary Log"). For example:

shell> mysqlbinlog binlog.000001 | mysql -u root
        -p

Or:

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

If the statements produced by mysqlbinlog may contain BLOB values, these may cause problems when mysql processes them. In this case, invoke mysql with the --binary-mode option.

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:

shell> mysqlbinlog binlog.000001 > tmpfileshell> ... edit tmpfile ...shell> mysql -u
        root -p < tmpfile

When mysqlbinlog is invoked with the --start-position option, it displays only those events 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 -u root -p #
        DANGER!!shell> mysqlbinlog binlog.000002 | mysql -u root -p #
        DANGER!!

Processing binary logs this way using multiple 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 mysql process 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 -u root -p

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

shell> mysqlbinlog binlog.000001 >
        /tmp/statements.sqlshell> mysqlbinlog binlog.000002 >>
        /tmp/statements.sqlshell> mysql -u root -p -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 with the LOCAL capability enabled. See Section 6.1.6, "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-#-#.




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