Read Causality in MariaDB: Async Replication, Galera and MariaDB MaxScale

Abstract

A single MariaDB node has intrinsic causal consistency: you can always read the rows you write. In a distributed MariaDB system, causal consistency is not there by default and other tools and methods need to be used. This presentation explores the various ways in which causality violations occur in asynchronous MariaDB Replication and Galera replication, how these present themselves and what tools are in MariaDB, Galera and how MariaDB MaxScale can help solve this.

Markus Mäkelä, MariaDB plc.

I’m a software engineer at MariaDB who works on the MaxScale database proxy. I’ve contributed small improvements to the MariaDB server as well as the connectors that it uses. My work with MaxScale has involved a lot of database clusters and all the problems that come with asynchronous replication and semi-synchronous systems like Galera at both at the client end as well as at the backend side of things.