With the brand-new Innovation Release 8.1.0, Oracle has once again given the MySQL InnoDB Cluster a new “feature”: “Read Replicas”. This allows an InnoDB cluster to be supplemented with additional read-only instances. This article explains how this works and why it can make sense. A, B, C An InnoDB cluster usually consists of three nodes that provi...

Now and then, smaller, or larger problems arise during consulting missions involving MySQL, which we would like to report here. In this case, our customer wanted to replace a MySQL single instance with a MySQL InnoDB cluster with three nodes. We have reported about the cluster here several times and do not discuss it in detail here. In this specifi...

Even as an experienced consultant, you don't think about many things until you are faced with them. I have put several InnoDB clusters including MySQL router into operation over the past few years. Up to now, this was always an interactive process where it was no problem to simply enter the passwords of privileged users (at the console). It was cle...

Configuration files are a constant source of errors. Especially with older systems (before version 8.0), which did not yet have the possibility to make online persistent changes (e.g. "set global persist…"), there were often minor problems. The parameter was set online (but volatile; i.e. not rebootable) due to a lack of downtime and was written to...

One key feature of Apache NiFi is scheduling. NiFi dataflows should cover streaming and batch use cases. But how can we connect both worlds together, and what settings are available? In this blog, we want to check the scheduling possibilities and show how to use them correctly. General scheduling options  The dataflow engineer has in total two...

Granting permissions on databases can be a tedious job. Especially assigning restrictive permissions à la "you may read all tables except for the information in database XYZ" was laborious. For such a task, the SELECT rights had to be defined for all databases that the user should be able to read. The unwanted database was simply given no rights. O...