Few people realize that Galera/Percona XtraDB (PXC) replication can be encrypted via SSL for secure transfer of your replicated data. Setting this up is actually quite easy to do and probably will look familiar to a lot of people.
I actually had more material than I covered (by design), but one thing I regret we didn’t cover was Flow control. So, I thought I’d write a post covering flow control because it is important to understand.
The phrase refers to the way cows tend to meander across the landscape in a remarkably consistent way. The cows reliably follow a consistent path. The paths tend to wander in ways that seem crazy to us.
Since our first post on transaction descriptors optimization introduced in Percona Server 5.5.30-30.2 and a followup by Dimitri Kravchuk we have received a large number of questions on why the benchmark results in both posts look rather different.
In my last post, I described a solution for keeping the caches of a MySQL standby server hot using MySQL slow logs with long_query_time set to 0. Here are a some lessons we learned when logging a high volume of queries to the slow log.
Swapping has always been something bad for MySQL performance but it is even more important for HA systems. It is so important to avoid swapping with HA that NDB cluster basically forbids calling malloc after the startup phase and hence its rather complex configuration.
MySQL provides the handy RESET SLAVE command. But as we’ll see, its behavior has changed along with the MySQL versions and it’s easy to shoot yourself in the foot if you use it incorrectly. So how do you safely disconnect a replication slave?