On previous posts about Group Replication consistency we:

1. introduced consistency levels;
2. explained how to configure the primary failover consistency;
3. presented how to configure transaction consistency levels to achieve the consistency required by your applications.

In blog 3. we presented the consistency levels: EVENTUAL, BEFORE, AFTER and BEFORE_AND_AFTER; their scopes: SESSION, GLOBAL; and their context: whether they only impact the ongoing transaction or all concurrent transactions.…

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This was not on the radar. I have never been proficient in Galera clusters and related technologies, and thus I hadn’t given much thought to Percona Xtradb Cluster (PXC), until Alkin approached me at FOSDEM, and proposed to extend dbdeployer features to support PXC. He mentioned that many support engineers at Percona use dbdeployer) on a daily basis and that the addition of PXC would be welcome.

I could not follow up …

Some months ago, Shlomi Noach published a series about Service Discovery.  In his posts, Shlomi describes many ways for an application to find the master.  He also gives detail on how these solutions cope with failing-over to a slave, including their integration with Orchestrator.

This is a great series, and I recommend its reading for everybody implementing master failover, with or without

This event was just awesome. We got 110 participants ! Thank you everybody and also a big thank to the speakers.

Here are the slides of all the sessions:

• MySQL Shell – A DevOps-engineer day with MySQL’s development and administration tool, Miguel Araújo
• MySQL Shell : the best DBA tool ? – How to use the MySQL Shell as a framework for DBAs, Frédéric Descamps
• Tuning MySQL 8.0 InnoDB for High Load, Dimitri Kravtchuk
• …

MySQL InnoDB is more and more popular. The adoption of it is even faster than I expected. Recently, during my travel in Stockholm, Sweden, a customer asked me what was the best practice to backup a cluster.

Since my interlocutor was a customer, the obvious choice is to use MySQL Enterprise Backup (known as MEB). Of course any other physical backup should be also fine.

The customer told me he was using cron to schedule his backup and was only using full backups… That’s perfect. So I told him that there is nothing complicated and that the cron job should something like:

mysqlbackup --with-timestamp --backup-dir /backup  backup

Of course, I do not recommend the use of --user clusteradmin --password=xxxxxin the cronjob but configure your crendentials using …

As we showed on the introduction post, in MySQL 8.0.14 Group Replication was once again improved. Now the developer can specify which is the consistency level of all group transactions or even of a single transaction.

Note that this is about consistency in terms of the global synchronization of transactions in the group.…

The MySQL Group Replication (GR) feature is a multi-primary update anywhere or single-primary replication plugin for MySQL with built-in conflict detection and resolution, automatic distributed recovery, and group membership.

Its goal it is to make high-availability (HA) simple with off-the-shelf hardware, not only to new applications but also existing ones – that was one of the motivations of the single-primary mode.…

If you are using MySQL InnoDB Cluster (Group Replication) with ProxySQL, you should be familiar with the 2 functions and 1 view required in SYS Schema that ProxySQL uses to see if a node is online, partitioned or not, and if it’s lagging or not (see link1 and link2).

I received recently a very valuable contribution from Bruce DeFrang that fixes a bug in one of the function that were added to SYS.

In fact, Bruce discovered that when a node was in RECOVERING state, it was not …

For the third year in a row, we will take advantage of the mass presence of our MySQL Engineers during FOSDEM to organize the pre-FOSDEM MySQL Day.

The program of this 3rd edition is already on track, thank you to all the speakers who already confirmed their participation.

As you know, MySQL InnoDB Cluster is a High Availability solution for MySQL. However more and more people are trying to use it as a Disaster Recovery solution with 2 data centers. Natively, this is not yet supported. But it’s already possible to realize such setup if we agree with the following points:

•  a human interaction is required in case of Disaster Recovery which, by my own experience, is often acceptable
• a human interaction is required if the any Primary-Master acting as asynchronous slave leaves its group  (crash, network problem, …) or becomes secondary

These are not big constraints and it’s relatively easily to deal with them.

The Architecture

The situation is as follow:

• 2 data centers (one active, one inactive, only used for disaster recovery)
• 2 MySQL InnoDB Clusters (one in each DC)
• 3 members in each …