In the spirit of sharing war stories and avoiding others to do the same mistakes as I did, here are some sequences of commands that you should avoid to run on a MariaDB slave that is lagging and which is using the GTID protocol.  Remember, do not run those because...

So, those bad commands are the following:

"STOP SLAVE; START SLAVE UNTIL ...;", or "STOP SLAVE; START SLAVE;" (to remove an

On Percona Live! Amsterdam 2015 we had a talk with Peter Boros about GTID replication.

Here are the slides.

Running gtid replication in production from Balazs Pocze

In my latest series of advanced replication features, I came across several usability issues, which I would like to recap here. For each section of this list of requests, I make a wish list, with some general comments.
INSTALLATIONAs the maintainer of MySQL Sandbox, a tool that wants to facilitate the installation of …

Previous episodes:

• MySQL replication monitoring 101

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topologyMySQL replication in action - Part 3 - All-masters P2P topology
Introducing star topology.In all-masters P2P topologies, we have seen that we have a way of deploying a topology where all nodes are masters, and achieve better efficiency and stability than ring topologies. That …

In the theoretical part of this series, we have seen the basics of monitoring. In that article, though, we have barely mentioned the new tools available in MySQL 5.7 and MariaDB 10. Let’s start from something that has the potential of dramatically changing replication as we know it.
Crash-safe tables and Global transaction identifiers in MySQL 5.6 and 5.7Global transaction identifiers (GTID) is a feature that has been in my wish list for long time, since the times I was working with the MySQL team. By the time I left Oracle, this feature was not even in the plans.
When MySQL 5.6 was first disclosed, the biggest improvement for replication was the introduction of crash-safe tables (see Status persistence in …

Beware the SST

In Percona XtraDB Cluster (PXC) I often run across users who are fearful of SSTs on their clusters. I’ve always maintained that if you can’t cope with a SST, PXC may not be right for you, but that doesn’t change the fact that SSTs with multiple Terabytes of data can be quite costly.

SST, by current definition, is a full backup of a Donor to Joiner.  The most popular method is Percona XtraBackup, so we’re talking about a donor node that must:

1. Run a full XtraBackup that reads its entire datadir
2. Keep up with Galera replication to it as much as possible (though laggy donors don’t send flow control)
3. Possibly still be serving application traffic if you don’t remove Donors from rotation.
…

Slave election is a popular HA architecture,  first MySQL MariaDB toolkit to manage switchover and failover in a correct way was introduce by Yoshinori Matsunobu into MHA.

Failover and switchover in asynchronous clusters require caution:

- The CAP theorem need to be satisfy. Getting strong consistency, require the slave election to reject transactions ending up in the old master when electing the candidate master.

- Slave election need to take care that all events on the old master are applied to the candidate master before switching roles.

- Should be instrumented to found a good candidate master and make sure it's setup to take the master role.

- Need topology detection, a master role can't be pre defined, as the role …

MySQL India team is back with another MySQL user camp.

The day of the week, time and venue remains the same:

Date: Jun 26th, 2015

Day : Friday

Time: 3-5:30 pm

Place: OC001, Block1, B wing, Kalyani Magnum Infotech Park, J.P Nagar, 7th Phase Bangalore, India

During our previous meetings we were requested by our attendees that they would like to hear about implementation of GTID by the MySQL community. We have listened to you and requested a community member to talk about their experience with the implementation of  GTID. Our first talk is :

• MySQL Tools Usage in Rakuten and Overview of Replication GTIDs

There is also a lot of interest in our new delivery vehicles for MySQL packages. Using the new YUM repos you can stay up to date with the latest MySQL releases. You need not  wait for your distro to update MySQL in their release …

The link to the slides of my talks can be found at the end of this post but first, let me share some thoughts about PLMCE.

Talking with people, I was surprised to be criticized of presenting only the good sides of my solution without giving credit to the good side of the alternative solutions.  More than surprised, I was also a little shocked as I want to be perceived as objective as possible.  Let me try to fix that:

• I am not a GTID and log-slaves detractor, I am a simplicity lover.
• I actually like GTIDs and I have some use-cases for them; one of  them is described in the MariaDB Knowledge Base (search for last_gtid in that page).
• But I think that using GTIDs in the slave protocol is complex and that a …

Dealing with the failure of a MySQL master is not simple.  The most common solution is to promote a slave as the new master but in an environment where you have many slaves, the asynchronous implementation of replication gets in your way.  The problem is that each slave might be in a different state:

some could be very close to the dead master, some could be missing the latest transactions, and