I was recently asked a question by mail about MySQL Lossless Semi-Synchronous Replication. As I think the answer could benefit many people, I am answering it in a blog post. The answer brings us to the internals of transaction committing, of semi-synchronous replication, of MySQL (server) crash recovery, and of storage engine (InnoDB) crash recovery. I am also debunking some misconceptions that I have often seen and heard repeated by many. Let’s start by stating one of those misconceptions.

One of those misconceptions is the following (this is NOT true): semi-synchronous enabled slaves are always the most up-to-date slaves (again, this is NOT true). If you hear it yourself, then please call people out on it to avoid this spreading more. Even if some slaves have semi-synchronous replication disabled (I will use semi-sync for …

This year again, the MySQL Team is eager to participate in the Oracle Open World conference. This is a great opportunity for our engineers and the entire MySQL Team to highlight what we’ve done, and also what we are working on. Another reason to be excited this year is our new participation to Code One, the Oracle developer focused conference. Oracle Code One will include a full track dedicated to MySQL.

This is very good news for everybody attending, from DBAs to developers, as we will offer even more great content ! This year, in both events, we will highlight how NoSQL+SQL=MySQL.

Our MySQL Engineers will deliver fantastic sessions about …

After having explained how to achieve HA for MySQL Router for people who doesn’t want to install the MySQL Router on the application servers and after having illustrated how to use Pacemaker, this article explains how to setup HA for MySQL Router using keepalived.

Keepalived is very popular, maybe because it’s also very easy to use. We can of course use 2 or more servers. The principle is the same as on the previous articles, if the router dies, the virtual IP used by the application server(s) to connect to MySQL is sent to another machine where mysqlrouter is still running.

Let’s have a look at the configuration, in this case we use 2 machines, mysql1 and …

This article will explain how to setup HA for MySQL Router as described in a previous article about where should the router stand.

For this setup, I will use Pacemaker (part of RedHat High Availability Add-on and available on RHEL, CentOS, Oracle Linux, …).

Of course we need a MySQL InnoDB Cluster but we won’t really use it for the HA setup of the MySQL Router.

Installing Pacemaker

The first step is to install pacemaker on all the machines we will use for our “MySQL Router Cluster”:

# yum install pacemaker pcs resource-agents

Now we need to start the pcsd service and enable it at boot (on all machines):

# systemctl start pcsd.service 
# systemctl enable pcsd.service

It’s time now to setup authentication, this operation is again …

As you know, MySQL InnoDB Cluster is composed of 3 elements:

• a group replication cluster of at least 3 servers
• the MySQL Shell used to manage the cluster
• the MySQL Router that send the traffic from the application server(s) to the cluster

When presenting the solution in conferences, one the main question is Where should I put the router ? and the answer is always the same: the best place to install the router is the application server !

The router is a very lightweight process that gets its configuration from the cluster’s metadata and doesn’t require a lot of resources or maintenance.

So the ideal setup is the following:

However for many (obscure?) reasons, sometimes people doesn’t want to have the MySQL …

Since MySQL 5.7 we have a new player in the field, MySQL InnoDB Cluster. This is an Oracle High Availability solution that can be easily installed over MySQL to get High Availability with multi-master capabilities and automatic failover.

This solution consists in 3 components: InnoDB Group Replication, MySQL Router and MySQL Shell, you can see how these components interact in this graphic:

In this three blog post series, we will cover each of this components to get a sense of what this tool provides and how it can help with architecture decisions.

Group Replication

This is …

As promised, here is a post more detailed on how to create a MySQL InnoDB Cluster using MySQL Shell and the AdminAPI.

First of all, as a good practice is never enough repeated, whatever the version of MySQL you are using, please use the latest MySQL Shell ! So if you are using 5.7, please use MySQL Shell 8.0.11. See this compatibility matrix or this official one.

dba class

The AdminAPI can be accessed by the MySQL Shell via the dba object. The reference manual for this class is here. The Shell …

I’m just back from a trip in Barcelona where I presented MySQL 8.0 InnoDB Cluster (at dataops and Barcelona MySQL Meetup) and the majority of feedback was great, but I also had some comments on the demos I showed. The first one was:

This is a joke of course (maybe it’s true for some), people found it very easy and they liked it.

But then, the second one was that all I showed wasn’t easy to find, some people who already played with the solution didn’t succeeded in creating a cluster so easily… not because they had errors or encountered bugs, but more because they just didn’t know how to do it.

The goal of this …

Next week I will be speaking at DataOps in Barcelona about MySQL 8.0 Document Store. If you don’t know it yet, I really invite you to join this talk, you will be very surprised about all MysQL can do in the NoSQL world !

There will be also a lot other MySQL related sessions by many good speakers of the MySQL Community.

As I will be in Barcelona, the Barcelona MySQL Meetup invited me to give a session about MySQL InnoDB Cluster and Group Replication and I will also share the stage with my friend and colleague …

From June 16th to 17th, the MySQL Team will be attending and speaking at the Hong Kong Open Source Conference 2018.

Unfortunately I won’t be present but some of my great colleagues will be speaking about MySQL.

If you are planning to attend HKOSCon2018, don’t miss their talks:

• Heading to the New Stage of MySQL 8.0 – Ivan Ma
• Crossing Relation and Document Database using …