Introduction # I recently encountered an intriguing bug. A user reported that their query was causing vtgate to fetch a large amount of data, sometimes resulting in an Out Of Memory (OOM) error. For a deeper understanding of grouping and aggregations on Vitess, I recommend reading this prior blog post. The Query # The problematic query was: selectsum(user.type)fromuserjoinuser_extraonuser.team_id=user_extra.idgroupbyuser_extra.idorderbyuser_extra.id;The planner was unable to delegate aggregation to MySQL, leading to the fetching of a significant amount of data for aggregation.

Vindex # Vitess uses Vindexes (short for Vitess Index) to associate rows in a table with a designated address known as Keyspace ID. This allows Vitess to direct a row to its intended destination, typically a shard within the cluster. Vindexes play a dual role: enabling data sharding through Primary Vindexes and facilitating global indexing via Secondary Vindexes. Through this mechanism, Vindexes serve as an indispensable tool for routing queries in a sharded database, ensuring optimal performance and scalability.

My name is Arvind Murty, and from May to July of 2023, I worked on Vitess via an internship with PlanetScale. I was first introduced to Vitess when I was in high school as a potential open-source project for me to work on. I had been interested in working on one because they’re a relatively easy way to get some real-world experience in large-scale software development. Vitess seemed like an good place to start, so I started contributing, mostly on internal cleanup.

Serverless databases are a modern approach to database technology. Unlike traditional databases, where users have to manage server infrastructure and capacity planning, serverless databases remove those complexities. Users can focus solely on their data and applications, leaving the database infrastructure provisioning, scaling, and maintenance to the service provider.

The post The Future of Databases: Exploring Serverless MySQL With PlanetScale appeared first on Devart Blog.