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This section describes the options that you can use on slave replication servers. You can specify these options either on the command line or in an option file.
On the master and each slave, you must use the
server-id option to establish a unique
replication ID. For each server, you should pick a unique positive
integer in the range from 1 to 232
– 1, and each ID must be different from every other ID.
Example: server-id=3
Options that you can use on the master server for controlling binary logging are described in Section 5.11.3, “The Binary Log”.
Some slave server replication options are handled in a special
way, in the sense that each is ignored if a
master.info file exists when the slave starts
and contains a value for the option. The following options are
handled this way:
--master-host
--master-user
--master-password
--master-port
--master-connect-retry
--master-ssl
--master-ssl-ca
--master-ssl-capath
--master-ssl-cert
--master-ssl-cipher
--master-ssl-key
The master.info file format in MySQL
5.0 includes values corresponding to the SSL options.
In addition, the file format includes as its first line the number
of lines in the file. (See Section 6.3.5, “Replication Relay and Status Files”.) If you
upgrade an older server (before MySQL 4.1.1) to a newer version,
the new server upgrades the master.info file
to the new format automatically when it starts. However, if you
downgrade a newer server to an older version, you should remove
the first line manually before starting the older server for the
first time.
If no master.info file exists when the slave
server starts, it uses the values for those options that are
specified in option files or on the command line. This occurs when
you start the server as a replication slave for the very first
time, or when you have run RESET SLAVE and then
have shut down and restarted the slave.
If the master.info file exists when the slave
server starts, the server uses its contents and ignores any
options that correspond to the values listed in the file. Thus, if
you start the slave server with different values of the startup
options that correspond to values in the
master.info file, the different values have
no effect, because the server continues to use the
master.info file. To use different values,
you must either restart after removing the
master.info file or (preferably) use the
CHANGE MASTER TO statement to reset the values
while the slave is running.
Suppose that you specify this option in your
my.cnf file:
[mysqld]
master-host=some_host
The first time you start the server as a replication slave, it
reads and uses that option from the my.cnf
file. The server then records the value in the
master.info file. The next time you start the
server, it reads the master host value from the
master.info file only and ignores the value
in the option file. If you modify the my.cnf
file to specify a different master host of
some_other_host, the change still has
no effect. You should use CHANGE MASTER TO
instead.
MySQL Enterprise. For expert advice regarding slave startup options subscribe to the MySQL Network Monitoring and Advisory Service. For more information see http://www.mysql.com/products/enterprise/advisors.html.
Because the server gives an existing
master.info file precedence over the startup
options just described, you might prefer not to use startup
options for these values at all, and instead specify them by using
the CHANGE MASTER TO statement. See
Section 13.6.2.1, “CHANGE MASTER TO Syntax”.
This example shows a more extensive use of startup options to configure a slave server:
[mysqld] server-id=2 master-host=db-master.mycompany.com master-port=3306 master-user=pertinax master-password=freitag master-connect-retry=60 report-host=db-slave.mycompany.com
The following list describes startup options for controlling
replication. Many of these options can be reset while the server
is running by using the CHANGE MASTER TO
statement. Others, such as the --replicate-*
options, can be set only when the slave server starts.
Normally, a slave does not log to its own binary log any
updates that are received from a master server. This option
tells the slave to log the updates performed by its SQL thread
to its own binary log. For this option to have any effect, the
slave must also be started with the --log-bin
option to enable binary logging.
--log-slave-updates is used when you want to
chain replication servers. For example, you might want to set
up replication servers using this arrangement:
A -> B -> C
Here, A serves as the master for the slave B, and B serves as
the master for the slave C. For this to work, B must be both a
master and a slave. You must start both A
and B with --log-bin to enable binary
logging, and B with the --log-slave-updates
option so that updates received from A are logged by B to its
binary log.
This option causes a server to print more messages to the
error log about what it is doing. With respect to replication,
the server generates warnings that it succeeded in
reconnecting after a network/connection failure, and informs
you as to how each slave thread started. This option is
enabled by default; to disable it, use
--skip-log-warnings. Aborted connections are
not logged to the error log unless the value is greater than
1.
--master-connect-retry=
seconds
The number of seconds that the slave thread sleeps before
trying to reconnect to the master in case the master goes down
or the connection is lost. The value in the
master.info file takes precedence if it
can be read. If not set, the default is 60. Connection retries
are not invoked until the slave times out reading data from
the master according to the value of
--slave-net-timeout. The number of
reconnection attempts is limited by the
--master-retry-count option.
The hostname or IP number of the master replication server.
The value in master.info takes precedence
if it can be read. If no master host is specified, the slave
thread does not start.
The name to use for the file in which the slave records
information about the master. The default name is
master.info in the data directory.
The password of the account that the slave thread uses for
authentication when it connects to the master. The value in
the master.info file takes precedence if
it can be read. If not set, an empty password is assumed.
The TCP/IP port number that the master is listening on. The
value in the master.info file takes
precedence if it can be read. If not set, the compiled-in
setting is assumed (normally 3306).
The number of times that the slave tries to connect to the
master before giving up. Reconnects are attempted at intervals
set by --master-connect-retry and reconnects
are triggered when data reads by the slave time out according
to the --slave-net-timeout option. The
default value is 86400.
--master-ssl,
--master-ssl-ca=,
file_name--master-ssl-capath=,
directory_name--master-ssl-cert=,
file_name--master-ssl-cipher=,
cipher_list--master-ssl-key=
file_name
These options are used for setting up a secure replication
connection to the master server using SSL. Their meanings are
the same as the corresponding --ssl,
--ssl-ca, --ssl-capath,
--ssl-cert, --ssl-cipher,
--ssl-key options that are described in
Section 5.8.7.3, “SSL Command Options”. The values in the
master.info file take precedence if they
can be read.
The username of the account that the slave thread uses for
authentication when it connects to the master. This account
must have the REPLICATION SLAVE privilege.
The value in the master.info file takes
precedence if it can be read. If the master username is not
set, the name test is assumed.
The size at which the server rotates relay log files automatically. For more information, see Section 6.3.5, “Replication Relay and Status Files”. The default size is 1GB.
When this option is given, the server allows no updates except
from users that have the SUPER privilege or
(on a slave server) from updates performed by slave threads.
On a slave server, this can be useful to ensure that the slave
accepts updates only from its master server and not from
clients. As of MySQL 5.0.16, this option does not apply to
TEMPORARY tables.
The name for the relay log. The default name is
host_name-relay-bin.nnnnnnhost_name is the name of the
slave server host and nnnnnn
indicates that relay logs are created in numbered sequence.
You can specify the option to create hostname-independent
relay log names, or if your relay logs tend to be big (and you
don't want to decrease max_relay_log_size)
and you need to put them in some area different from the data
directory, or if you want to increase speed by balancing load
between disks.
The name to use for the relay log index file. The default name
is
host_name-relay-bin.indexhost_name is the name of the slave
server.
--relay-log-info-file=
file_name
The name to use for the file in which the slave records
information about the relay logs. The default name is
relay-log.info in the data directory.
Disable or enable automatic purging of relay logs as soon as
they are not needed any more. The default value is 1
(enabled). This is a global variable that can be changed
dynamically with SET GLOBAL relay_log_purge =
.
N
This option places an upper limit on the total size in bytes
of all relay logs on the slave. A value of 0 means “no
limit.” This is useful for a slave server host that has
limited disk space. When the limit is reached, the I/O thread
stops reading binary log events from the master server until
the SQL thread has caught up and deleted some unused relay
logs. Note that this limit is not absolute: There are cases
where the SQL thread needs more events before it can delete
relay logs. In that case, the I/O thread exceeds the limit
until it becomes possible for the SQL thread to delete some
relay logs, because not doing so would cause a deadlock. You
should not set --relay-log-space-limit to
less than twice the value of
--max-relay-log-size (or
--max-binlog-size if
--max-relay-log-size is 0). In that case,
there is a chance that the I/O thread waits for free space
because --relay-log-space-limit is exceeded,
but the SQL thread has no relay log to purge and is unable to
satisfy the I/O thread. This forces the I/O thread to
temporarily ignore --relay-log-space-limit.
Tell the slave to restrict replication to statements where the
default database (that is, the one selected by
USE) is db_name.
To specify more than one database, use this option multiple
times, once for each database. Note that this does not
replicate cross-database statements such as UPDATE
while having selected a different database
or no database.
some_db.some_table SET
foo='bar'
To specify multiple databases you must use multiple instances of this option. Because database names can contain commas, if you supply a comma separated list then the list will be treated as the name of a single database.
An example of what does not work as you might expect: If the
slave is started with --replicate-do-db=sales
and you issue the following statements on the master, the
UPDATE statement is
not replicated:
USE prices; UPDATE sales.january SET amount=amount+1000;
The main reason for this “just check the default
database” behavior is that it is difficult from the
statement alone to know whether it should be replicated (for
example, if you are using multiple-table
DELETE statements or multiple-table
UPDATE statements that act across multiple
databases). It is also faster to check only the default
database rather than all databases if there is no need.
If you need cross-database updates to work, use
--replicate-wild-do-table=
instead. See Section 6.9, “How Servers Evaluate Replication Rules”.
db_name.%
--replicate-do-table=
db_name.tbl_name
Tell the slave thread to restrict replication to the specified
table. To specify more than one table, use this option
multiple times, once for each table. This works for
cross-database updates, in contrast to
--replicate-do-db. See
Section 6.9, “How Servers Evaluate Replication Rules”.
Tells the slave to not replicate any statement where the
default database (that is, the one selected by
USE) is db_name.
To specify more than one database to ignore, use this option
multiple times, once for each database. You should not use
this option if you are using cross-database updates and you do
not want these updates to be replicated. See
Section 6.9, “How Servers Evaluate Replication Rules”.
An example of what does not work as you might expect: If the
slave is started with
--replicate-ignore-db=sales and you issue the
following statements on the master, the
UPDATE statement is
replicated:
USE prices; UPDATE sales.january SET amount=amount+1000;
In the preceding example the statement is replicated because
--replicate-ignore-db only applies to the
default database (set through the USE
statement). Because the sales database
was specified explicitly in the statement, the statement has
not been filtered.
If you need cross-database updates to work, use
--replicate-wild-ignore-table=
instead. See Section 6.9, “How Servers Evaluate Replication Rules”.
db_name.%
--replicate-ignore-table=
db_name.tbl_name
Tells the slave thread to not replicate any statement that
updates the specified table, even if any other tables might be
updated by the same statement. To specify more than one table
to ignore, use this option multiple times, once for each
table. This works for cross-database updates, in contrast to
--replicate-ignore-db. See
Section 6.9, “How Servers Evaluate Replication Rules”.
--replicate-rewrite-db=
from_name->to_name
Tells the slave to translate the default database (that is,
the one selected by USE) to
to_name if it was
from_name on the master. Only
statements involving tables are affected (not statements such
as CREATE DATABASE, DROP
DATABASE, and ALTER DATABASE),
and only if from_name is the
default database on the master. This does not work for
cross-database updates. The database name translation is done
before the --replicate-*
rules are tested.
If you use this option on the command line and the
‘>’ character is special to
your command interpreter, quote the option value. For example:
shell> mysqld --replicate-rewrite-db="olddb->newdb"
To be used on slave servers. Usually you should use the
default setting of 0, to prevent infinite loops caused by
circular replication. If set to 1, the slave does not skip
events having its own server ID. Normally, this is useful only
in rare configurations. Cannot be set to 1 if
--log-slave-updates is used. Note that by
default the slave I/O thread does not even write binary log
events to the relay log if they have the slave's server id
(this optimization helps save disk usage). So if you want to
use --replicate-same-server-id, be sure to
start the slave with this option before you make the slave
read its own events that you want the slave SQL thread to
execute.
--replicate-wild-do-table=
db_name.tbl_name
Tells the slave thread to restrict replication to statements
where any of the updated tables match the specified database
and table name patterns. Patterns can contain the
‘%’ and
‘_’ wildcard characters, which
have the same meaning as for the LIKE
pattern-matching operator. To specify more than one table, use
this option multiple times, once for each table. This works
for cross-database updates. See
Section 6.9, “How Servers Evaluate Replication Rules”.
Example: --replicate-wild-do-table=foo%.bar%
replicates only updates that use a table where the database
name starts with foo and the table name
starts with bar.
If the table name pattern is %, it matches
any table name and the option also applies to database-level
statements (CREATE DATABASE, DROP
DATABASE, and ALTER DATABASE).
For example, if you use
--replicate-wild-do-table=foo%.%,
database-level statements are replicated if the database name
matches the pattern foo%.
To include literal wildcard characters in the database or
table name patterns, escape them with a backslash. For
example, to replicate all tables of a database that is named
my_own%db, but not replicate tables from
the my1ownAABCdb database, you should
escape the ‘_’ and
‘%’ characters like this:
--replicate-wild-do-table=my\_own\%db. If
you're using the option on the command line, you might need to
double the backslashes or quote the option value, depending on
your command interpreter. For example, with the
bash shell, you would need to type
--replicate-wild-do-table=my\\_own\\%db.
--replicate-wild-ignore-table=
db_name.tbl_name
Tells the slave thread not to replicate a statement where any table matches the given wildcard pattern. To specify more than one table to ignore, use this option multiple times, once for each table. This works for cross-database updates. See Section 6.9, “How Servers Evaluate Replication Rules”.
Example:
--replicate-wild-ignore-table=foo%.bar% does
not replicate updates that use a table where the database name
starts with foo and the table name starts
with bar.
For information about how matching works, see the description
of the --replicate-wild-do-table option. The
rules for including literal wildcard characters in the option
value are the same as for
--replicate-wild-ignore-table as well.
The hostname or IP number of the slave to be reported to the
master during slave registration. This value appears in the
output of SHOW SLAVE HOSTS on the master
server. Leave the value unset if you do not want the slave to
register itself with the master. Note that it is not
sufficient for the master to simply read the IP number of the
slave from the TCP/IP socket after the slave connects. Due to
NAT and other routing issues, that IP may not be valid for
connecting to the slave from the master or other hosts.
The account password of the slave to be reported to the master
during slave registration. This value appears in the output of
SHOW SLAVE HOSTS on the master server if
the --show-slave-auth-info option is given.
The TCP/IP port number for connecting to the slave, to be reported to the master during slave registration. Set this only if the slave is listening on a non-default port or if you have a special tunnel from the master or other clients to the slave. If you are not sure, do not use this option.
The account username of the slave to be reported to the master
during slave registration. This value appears in the output of
SHOW SLAVE HOSTS on the master server if
the --show-slave-auth-info option is given.
id="option_mysqld_slave_compressed_protocol"
--show-slave-auth-info
Display slave usernames and passwords in the output of
SHOW SLAVE HOSTS on the master server for
slaves started with the --report-user and
--report-password options.
Tells the slave server not to start the slave threads when the
server starts. To start the threads later, use a
START SLAVE statement.
--slave_compressed_protocol={0|1}
If this option is set to 1, use compression for the slave/master protocol if both the slave and the master support it. The default is 0 (no compression).
The name of the directory where the slave creates temporary
files. This option is by default equal to the value of the
tmpdir system variable. When the slave SQL
thread replicates a LOAD DATA INFILE
statement, it extracts the file to be loaded from the relay
log into temporary files, and then loads these into the table.
If the file loaded on the master is huge, the temporary files
on the slave are huge, too. Therefore, it might be advisable
to use this option to tell the slave to put temporary files in
a directory located in some filesystem that has a lot of
available space. In that case, the relay logs are huge as
well, so you might also want to use the
--relay-log option to place the relay logs in
that filesystem.
The directory specified by this option should be located in a
disk-based filesystem (not a memory-based filesystem) because
the temporary files used to replicate LOAD DATA
INFILE must survive machine restarts. The directory
also should not be one that is cleared by the operating system
during the system startup process.
The number of seconds to wait for more data from the master
before the slave considers the connection broken, aborts the
read, and tries to reconnect. The first retry occurs
immediately after the timeout. The interval between retries is
controlled by the --master-connect-retry
option and the number of reconnection attempts is limited by
the --master-retry-count option. The default
is 3600 seconds (one hour).
--slave-skip-errors=[
err_code1,err_code2,...|all]
Normally, replication stops when an error occurs on the slave. This gives you the opportunity to resolve the inconsistency in the data manually. This option tells the slave SQL thread to continue replication when a statement returns any of the errors listed in the option value.
Do not use this option unless you fully understand why you are getting errors. If there are no bugs in your replication setup and client programs, and no bugs in MySQL itself, an error that stops replication should never occur. Indiscriminate use of this option results in slaves becoming hopelessly out of synchrony with the master, with you having no idea why this has occurred.
For error codes, you should use the numbers provided by the
error message in your slave error log and in the output of
SHOW SLAVE STATUS.
Appendix B, Errors, Error Codes, and Common Problems, lists server error codes.
You can also (but should not) use the very non-recommended
value of all to cause the slave to ignore
all error messages and keeps going regardless of what happens.
Needless to say, if you use all, there are
no guarantees regarding the integrity of your data. Please do
not complain (or file bug reports) in this case if the slave's
data is not anywhere close to what it is on the master.
You have been warned.
Examples:
--slave-skip-errors=1062,1053 --slave-skip-errors=all