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:
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
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 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*/;
/*!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.
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.
The other flags are reserved for future use.
