Syntax:
CHANGE MASTER TO option [, option] ...

option:
    MASTER_BIND = 'interface_name'
  | MASTER_HOST = 'host_name'
  | MASTER_USER = 'user_name'
  | MASTER_PASSWORD = 'password'
  | MASTER_PORT = port_num
  | MASTER_CONNECT_RETRY = interval
  | MASTER_RETRY_COUNT = count
  | MASTER_DELAY = interval
  | MASTER_HEARTBEAT_PERIOD = interval
  | MASTER_LOG_FILE = 'master_log_name'
  | MASTER_LOG_POS = master_log_pos
  | MASTER_AUTO_POSITION = {0|1}
  | RELAY_LOG_FILE = 'relay_log_name'
  | RELAY_LOG_POS = relay_log_pos
  | MASTER_SSL = {0|1}
  | MASTER_SSL_CA = 'ca_file_name'
  | MASTER_SSL_CAPATH = 'ca_directory_name'
  | MASTER_SSL_CERT = 'cert_file_name'
  | MASTER_SSL_CRL = 'crl_file_name'
  | MASTER_SSL_CRLPATH = 'crl_directory_name'
  | MASTER_SSL_KEY = 'key_file_name'
  | MASTER_SSL_CIPHER = 'cipher_list'
  | MASTER_SSL_VERIFY_SERVER_CERT = {0|1}
  | IGNORE_SERVER_IDS = (server_id_list)

server_id_list:
    [server_id [, server_id] ... ]

CHANGE MASTER TO changes the parameters that the slave server uses for
connecting to the master server, for reading the master binary log, and
reading the slave relay log. It also updates the contents of the master
info and relay log info repositories (see
http://dev.mysql.com/doc/refman/5.6/en/slave-logs.html). To use CHANGE
MASTER TO, the slave replication threads must be stopped (use STOP
SLAVE if necessary). In MySQL 5.6.11 and later, gtid_next must also be
set to AUTOMATIC (Bug #16062608).

Options not specified retain their value, except as indicated in the
following discussion. Thus, in most cases, there is no need to specify
options that do not change. For example, if the password to connect to
your MySQL master has changed, you just need to issue these statements
to tell the slave about the new password:

STOP SLAVE; -- if replication was running
CHANGE MASTER TO MASTER_PASSWORD='new3cret';
START SLAVE; -- if you want to restart replication

MASTER_HOST, MASTER_USER, MASTER_PASSWORD, and MASTER_PORT provide
information to the slave about how to connect to its master:

o MASTER_HOST and MASTER_PORT are the host name (or IP address) of the
  master host and its TCP/IP port.

  *Note*: Replication cannot use Unix socket files. You must be able to
  connect to the master MySQL server using TCP/IP.

  If you specify the MASTER_HOST or MASTER_PORT option, the slave
  assumes that the master server is different from before (even if the
  option value is the same as its current value.) In this case, the old
  values for the master binary log file name and position are
  considered no longer applicable, so if you do not specify
  MASTER_LOG_FILE and MASTER_LOG_POS in the statement,
  MASTER_LOG_FILE='' and MASTER_LOG_POS=4 are silently appended to it.

  Setting MASTER_HOST='' (that is, setting its value explicitly to an
  empty string) is not the same as not setting MASTER_HOST at all.
  Beginning with MySQL 5.5, trying to set MASTER_HOST to an empty
  string fails with an error. Previously, setting MASTER_HOST to an
  empty string caused START SLAVE subsequently to fail. (Bug #28796)

  In MySQL 5.6.5 and later, values used for MASTER_HOST and other
  CHANGE MASTER TO options are checked for linefeed (\n or 0x0A)
  characters; the presence of such characters in these values causes
  the statement to fail with ER_MASTER_INFO. (Bug #11758581, Bug
  #50801)

o MASTER_USER and MASTER_PASSWORD are the user name and password of the
  account to use for connecting to the master.

  In MySQL 5.6.4 and later, MASTER_USER cannot be made empty; setting
  MASTER_USER = '' or leaving it unset when setting a value for for
  MASTER_PASSWORD causes an error (Bug #13427949).

  Currently, a password used for a replication slave account is
  effectively limited to 32 characters in length; if the password is
  longer, any excess characters are truncated. This is not due to any
  limit imposed by the MySQL Server generally, but rather is an issue
  specific to MySQL Replication. (For more information, see Bug
  #43439.)

  The text of a running CHANGE MASTER TO statement, including values
  for MASTER_USER and MASTER_PASSWORD, can be seen in the output of a
  concurrent SHOW PROCESSLIST statement. (The complete text of a START
  SLAVE statement is also visible to SHOW PROCESSLIST.)

The MASTER_SSL_xxx options provide information about using SSL for the
connection. They correspond to the --ssl-xxx options described in
http://dev.mysql.com/doc/refman/5.6/en/ssl-options.html, and
http://dev.mysql.com/doc/refman/5.6/en/replication-solutions-ssl.html.
These options can be changed even on slaves that are compiled without
SSL support. They are saved to the master info repository, but are
ignored if the slave does not have SSL support enabled. MASTER_SSL_CRL
and MASTER_SSL_CRLPATH were added in MySQL 5.6.3.

MASTER_CONNECT_RETRY specifies how many seconds to wait between connect
retries. The default is 60.

MASTER_RETRY_COUNT, added in MySQL 5.6.1, limits the number of
reconnection attempts and updates the value of the Master_Retry_Count
column in the output of SHOW SLAVE STATUS (also added in MySQL 5.6.1).
The default value is 24 * 3600 = 86400. MASTER_RETRY_COUNT is intended
to replace the older --master-retry-count server option, and is now the
preferred method for setting this limit. You are encouraged not to rely
on --master-retry-count in new applications and, when upgrading to
MySQL 5.6.1 or later from earlier versions of MySQL, to update any
existing applications that rely on it, so that they use CHANGE MASTER
TO ... MASTER_RETRY_COUNT instead.

MASTER_DELAY specifies how many seconds behind the master the slave
must lag. An event received from the master is not executed until at
least interval seconds later than its execution on the master. The
default is 0. An error occurs if interval is not a nonnegative integer
in the range from 0 to 231-1. For more information, see
http://dev.mysql.com/doc/refman/5.6/en/replication-delayed.html. This
option was added in MySQL 5.6.0.

MASTER_BIND is for use on replication slaves having multiple network
interfaces, and determines which of the slave's network interfaces is
chosen for connecting to the master.

The address configured with this option, if any, can be seen in the
Master_Bind column of the output from SHOW SLAVE STATUS. If you are
using slave status log tables (server started with
--master-info-repository=TABLE), the value can also be seen as the
Master_bind column of the mysql.slave_master_info table.

The ability to bind a replication slave to a specific network interface
was added in MySQL 5.6.2. This is also supported by MySQL Cluster NDB
7.3.1 and later.

MASTER_HEARTBEAT_PERIOD sets the interval in seconds between
replication heartbeats. Whenever the master's binary log is updated
with an event, the waiting period for the next heartbeat is reset.
interval is a decimal value having the range 0 to 4294967 seconds and a
resolution in milliseconds; the smallest nonzero value is 0.001.
Heartbeats are sent by the master only if there are no unsent events in
the binary log file for a period longer than interval.

If you are logging master connection information to tables,
MASTER_HEARTBEAT_PERIOD can be seen as the value of the Heartbeat
column of the mysql.slave_master_info table.

Setting interval to 0 disables heartbeats altogether. The default value
for interval is equal to the value of slave_net_timeout divided by 2.

Setting @@global.slave_net_timeout to a value less than that of the
current heartbeat interval results in a warning being issued. The
effect of issuing RESET SLAVE on the heartbeat interval is to reset it
to the default value.

MASTER_LOG_FILE and MASTER_LOG_POS are the coordinates at which the
slave I/O thread should begin reading from the master the next time the
thread starts. RELAY_LOG_FILE and RELAY_LOG_POS are the coordinates at
which the slave SQL thread should begin reading from the relay log the
next time the thread starts. If you specify either of MASTER_LOG_FILE
or MASTER_LOG_POS, you cannot specify RELAY_LOG_FILE or RELAY_LOG_POS.
In MySQL 5.6.5 and later, if you specify either of MASTER_LOG_FILE or
MASTER_LOG_POS, you also cannot specify MASTER_AUTO_POSITION = 1
(described later in this section). If neither of MASTER_LOG_FILE or
MASTER_LOG_POS is specified, the slave uses the last coordinates of the
slave SQL thread before CHANGE MASTER TO was issued. This ensures that
there is no discontinuity in replication, even if the slave SQL thread
was late compared to the slave I/O thread, when you merely want to
change, say, the password to use.

MASTER_AUTO_POSITION was added in MySQL 5.6.5. If MASTER_AUTO_POSITION
= 1 is used with CHANGE MASTER TO, the slave attempts to connect to the
master using the GTID-based replication protocol.

When using GTIDs, the slave tells the master which transactions it has
already received, executed, or both. To compute this set, it reads the
global value of gtid_executed and the value of the Retrieved_gtid_set
column from SHOW SLAVE STATUS. Since the GTID of the last transmitted
transaction is included in Retrieved_gtid_set even if the transaction
was only partially transmitted, the last received GTID is subtracted
from this set. Thus, the slave computes the following set:

UNION(@@global.gtid_executed, Retrieved_gtid_set - last_received_GTID)

This set is sent to the master as part of the initial handshake, and
the master sends back all transactions that it has executed which are
not part of the set. If any of these transactions have been already
purged from the master's binary log, the master sends the error
ER_MASTER_HAS_PURGED_REQUIRED_GTIDS to the slave, and replication does
not start.

When GTID-based replication is employed, the coordinates represented by
MASTER_LOG_FILE and MASTER_LOG_POS are not used, and global transaction
identifiers are used instead. Thus the use of either or both of these
options together with MASTER_AUTO_POSITION causes an error.

Beginning with MySQL 5.6.10, you can see whether replication is running
with autopositioning enabled by checking the output of SHOW SLAVE
STATUS. (Bug #15992220)

gtid_mode must also be enabled before issuing CHANGE MASTER TO ...
MASTER_AUTO_POSITION = 1. Otherwise, the statement fails with an error.

To revert to the older file-based replication protocol after using
GTIDs, you can issue a new CHANGE MASTER TO statement that specifies
MASTER_AUTO_POSITION = 0, as well as at least one of MASTER_LOG_FILE or
MASTER_LOG_POSITION.

CHANGE MASTER TO deletes all relay log files and starts a new one,
unless you specify RELAY_LOG_FILE or RELAY_LOG_POS. In that case, relay
log files are kept; the relay_log_purge global variable is set silently
to 0.

Prior to MySQL 5.6.2, RELAY_LOG_FILE required an absolute path.
Beginning with MySQL 5.6.2, the path can be relative, in which case it
is assumed to be relative to the slave's data directory. (Bug #12190)

IGNORE_SERVER_IDS takes a comma-separated list of 0 or more server IDs.
Events originating from the corresponding servers are ignored, with the
exception of log rotation and deletion events, which are still recorded
in the relay log.

In circular replication, the originating server normally acts as the
terminator of its own events, so that they are not applied more than
once. Thus, this option is useful in circular replication when one of
the servers in the circle is removed. Suppose that you have a circular
replication setup with 4 servers, having server IDs 1, 2, 3, and 4, and
server 3 fails. When bridging the gap by starting replication from
server 2 to server 4, you can include IGNORE_SERVER_IDS = (3) in the
CHANGE MASTER TO statement that you issue on server 4 to tell it to use
server 2 as its master instead of server 3. Doing so causes it to
ignore and not to propagate any statements that originated with the
server that is no longer in use.

If a CHANGE MASTER TO statement is issued without any IGNORE_SERVER_IDS
option, any existing list is preserved; RESET SLAVE also has no effect
on the server ID list. To clear the list of ignored servers, it is
necessary to use the option with an empty list:

CHANGE MASTER TO IGNORE_SERVER_IDS = ();

If IGNORE_SERVER_IDS contains the server's own ID and the server was
started with the --replicate-same-server-id option enabled, an error
results.

In MySQL 5.6, the master info repository and the output of SHOW SLAVE
STATUS provide the list of servers that are currently ignored. For more
information, see
http://dev.mysql.com/doc/refman/5.6/en/slave-logs-status.html, and
[HELP SHOW SLAVE STATUS].

In MySQL 5.6, invoking CHANGE MASTER TO causes the previous values for
MASTER_HOST, MASTER_PORT, MASTER_LOG_FILE, and MASTER_LOG_POS to be
written to the error log, along with other information about the
slave's state prior to execution.

In MySQL 5.6.7 and later, CHANGE MASTER TO causes an implicit commit of
an ongoing transaction. See
http://dev.mysql.com/doc/refman/5.6/en/implicit-commit.html.

CHANGE MASTER TO is useful for setting up a slave when you have the
snapshot of the master and have recorded the master binary log
coordinates corresponding to the time of the snapshot. After loading
the snapshot into the slave to synchronize it with the master, you can
run CHANGE MASTER TO MASTER_LOG_FILE='log_name', MASTER_LOG_POS=log_pos
on the slave to specify the coordinates at which the slave should begin
reading the master binary log.

The following example changes the master server the slave uses and
establishes the master binary log coordinates from which the slave
begins reading. This is used when you want to set up the slave to
replicate the master:

CHANGE MASTER TO
  MASTER_HOST='master2.mycompany.com',
  MASTER_USER='replication',
  MASTER_PASSWORD='bigs3cret',
  MASTER_PORT=3306,
  MASTER_LOG_FILE='master2-bin.001',
  MASTER_LOG_POS=4,
  MASTER_CONNECT_RETRY=10;

The next example shows an operation that is less frequently employed.
It is used when the slave has relay log files that you want it to
execute again for some reason. To do this, the master need not be
reachable. You need only use CHANGE MASTER TO and start the SQL thread
(START SLAVE SQL_THREAD):

CHANGE MASTER TO
  RELAY_LOG_FILE='slave-relay-bin.006',
  RELAY_LOG_POS=4025;

URL: http://dev.mysql.com/doc/refman/5.6/en/change-master-to.html

