How to re-sync the Mysql DB if Master and slave have different database incase of Mysql replication?

Question

Mysql Server1 is running as MASTER.
Mysql Server2 is running as SLAVE.

Now DB replication is happeni

Answer 1

I am very late to this question, however I did encounter this problem and, after much searching, I found this information from Bryan Kennedy: http://plusbryan.com/mysql-replication-without-downtime

On Master take a backup like this:
mysqldump --skip-lock-tables --single-transaction --flush-logs --hex-blob --master-data=2 -A > ~/dump.sql

Now, examine the head of the file and jot down the values for MASTER_LOG_FILE and MASTER_LOG_POS. You will need them later: head dump.sql -n80 | grep "MASTER_LOG"

Copy the "dump.sql" file over to Slave and restore it: mysql -u mysql-user -p < ~/dump.sql

Connect to Slave mysql and run a command like this: CHANGE MASTER TO MASTER_HOST='master-server-ip', MASTER_USER='replication-user', MASTER_PASSWORD='slave-server-password', MASTER_LOG_FILE='value from above', MASTER_LOG_POS=value from above; START SLAVE;

To check the progress of Slave: SHOW SLAVE STATUS;

If all is well, Last_Error will be blank, and Slave_IO_State will report “Waiting for master to send event”. Look for Seconds_Behind_Master which indicates how far behind it is. YMMV. :)