Syncing differences in MySQL cluster

(Originally posted on kinja ops blog)

In my last article I showed how to fix replication errors on slaves, but I’ve made a mistake: my current example wasn’t good, after skipping the command or inserting and empty transaction the dataset was different because of a timestamp holding date column which is CURRENT_TIMESTAMP default. Fixing the error solved the problem of the running replication thread, but the data wasn’t same on the hosts. I decided to leave this as-is, and instead of recreating the test, I rather show how to sync the databases.

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Fixing broken replication in a GTID based scenario

(Originally posted in kinja ops blog)

Every MySQL DBA should deal with the situation, when there were an accidental write on one of the slaves. Changing replication to GTID will change the way how we should deal with that problem.

Let’s check out!

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MySQL replication module upgrade

(Originally posted in kinja ops blog)

Yesterday I’ve put some new features into the ansible’s mysql_replication module, because we are planning to move to GTID based replication from the good old binlog position based one, and the module wasn’t aware of.

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GTID based replication showcase

(Originally posted in kinja ops blog)

We are in the middle of switching to GTID based replication from the good old logfile & log position based replication.

But what is GTID? GTID is an abbreviation of ‘GLOBAL TRANSACTION ID’ what speaks for itself: each transaction of a mysql cluster got its globally unique transaction ID, and the DBA have not spend time with positioning slaves, as well as we don’t have to ‘freeze’ any of the servers because of a master failover. The only thing we have to care about: to know what server should be used as a replication master.

OK, what was the problem with the old file-based replication?

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