SQL Statements for Controlling Replica Servers If you specify  SOURCE_HOST  or  SOURCE_PORT , the replica assumes that the source 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 In this case, the old values for the source’s binary log file name and position are considered no longer applicable, so if you do not specify  SOURCE_LOG_FILE  and SOURCE_LOG_POS  in the statement,  SOURCE_LOG_FILE=’’  and SOURCE_LOG_POS=4  are silently appended to it. Replication cannot use Unix socket files. You must be able to connect to the replication source server using TCP/IP. The password used for a replication user account in a  CHANGE REPLICATION SOURCE TO  statement is limited to 32 characters in length. Trying to use a password of more than 32 characters causes CHANGE REPLICATION SOURCE TO  to fail. If neither of  SOURCE_LOG_FILE  or  SOURCE_LOG_POS  is specified, the replica uses the last coordinates of the  replication SQL thread  before CHANGE REPLICATION SOURCE TO  was issued. This ensures that there is no discontinuity in replication, even if the replication SQL thread was late compared to the replication I/O thread. If you specify either of  SOURCE_LOG_FILE  or  SOURCE_LOG_POS , you cannot specify  SOURCE_AUTO_POSITION = 1 , which is for GTID- based replication. SOURCE_LOG_POS  in the statement,  SOURCE_LOG_FILE=’’  and SOURCE_LOG_POS=4  are silently appended to it. Setting  SOURCE_HOST=’’  (that is, setting its value explicitly to an empty string) is  not  the same as not setting  SOURCE_HOST  at all. Trying to set  SOURCE_HOST  to an empty string fails with an error. SOURCE_LOG_FILE , The binary log file name, and the location in that file, at which the SOURCE_LOG_POS replication I/O thread begins reading from the source’s binary log the next time the thread starts. Specify these options if you are using binary log file position based replication.  SOURCE_LOG_FILE  must include the numeric suffix of a specific binary log file that is available on the source server, for example,  SOURCE_LOG_FILE=’binlog.000145’ . SOURCE_LOG_POS  is the numeric position for the replica to start reading in that file.  SOURCE_LOG_POS=4  represents the start of the events in a binary log file. SOURCE_PASSWORD The password for the replication user account to use for connecting to the replication source server. If you specify  SOURCE_PASSWORD , SOURCE_USER  is also required. SOURCE_PORT The TCP/IP port number that the replica uses to connect to the replication source server. SOURCE_PUBLIC_KEY_PATH Enables RSA key pair-based password exchange by providing the path name to a file containing a replica-side copy of the public key required by the source. The file must be in PEM format. This option Note 2770