Quarantine DB Talk 2020: ksqlDB: A Stream-Relational Database System

ksqlDB is a distributed event streaming database system that allows users to express SQL queries over relational tables and event streams. The project was released by Confluent in 2017 and is hosted on Github and developed with an open-source spirit. ksqlDB is built on top of Apache Kafka, a distributed event streaming platform. In this talk, we discuss ksqlDB's architecture that is influenced by Apache Kafka and its stream processing library, Kafka Streams. We explain how ksqlDB executes continuous queries, Read More

Quarantine DB Talk 2020: The Cascades Framework for Query Optimization at Microsoft

The Cascades framework was an academic project introduced 25 years ago as a foundation for modern query optimizers. It provides extensibility, memoization-based dynamic programming, an algebraic representation of logical and physical operator trees, and manipulation of such trees using transformation rules to enable cost-based query optimization. Cascades provides a clean framework/skeleton for optimizer development, but it needs to be instantiated with domain-knowledge and augmented in several directions to cope with real-world workloads in an industrial setting. We will describe some Read More

Quarantine DB Talk 2020: PlanetScale: Query Planning for a Sharded System like Vitess

Traditional query planning involves parsing of an input SQL into an AST, and then transforming it into primitives which can later be sent through an optimizer. However, in a sharded system, each leaf node is a full relational engine that is capable of doing its own optimizations. So, the traditional approach may not work for such a system. And who knows if the finally reconstructed query would be correctly optimized by the underlying engine? The Vitess VTGate proxy uses a Read More

Quarantine DB Talk 2020: Databricks: A Deep Dive into Spark SQL’s Catalyst Optimizer

Catalyst is the SQL query optimizer in Spark SQL. It is one of the most important components of Apache Spark, as it powers major Spark APIs like SQL, DataFrames/Datasets, as well as Structured Streaming. Unlike many traditional SQL systems, Spark enables users to query data in arbitrary formats stored in arbitrary locations at scale. While being powerful, this also imposes extra query planning challenges such as statistics collection and cost estimation, which further affect performance negatively. In this talk, we Read More

Quarantine DB Talk 2020: Refactoring Query Processing in MySQL

MySQL is often called the world's most popular open source DBMS, and it's certainly one of the most used. MySQL grew up with the open source movement and the public Internet and became a part of the famous LAMP stack. Today, MySQL server are still powering a huge number of web sites. A lot has changed in MySQL in the 25 years since the initial release, but a lot of the core code has also remained almost unchanged. The query Read More

Fall 2020: Prashanth Menon (CMU)

Just-in-time (JIT) query compilation is a technique to improve analytical query performance in database management systems (DBMSs). But the cost of compiling each query can be significant relative to its execution time. This overhead prohibits the DBMS from employing well-known adaptive query processing (AQP) methods to generate a new plan for a query if data distributions do not match the optimizer's estimations. The optimizer could eagerly generate multiple sub-plans for a query, but it can only include a few alternatives Read More

Quarantine DB Talk 2020: CrocodileDB: Resource Efficient Database Execution

The coming end of Moore’s law requires that data systems be more judicious with computation and resources as the growth in data outpaces the availability of computational resources. Current database systems are eager and aggressively consume resources to immediately and quickly complete the task at hand. Intelligently deferring a task to a later point in time can increase result reuse, reduce work that might later be invalidated, or avoid unnecessary work altogether. In this talk I will introduce CrocodileDB, a Read More

Quarantine DB Talk 2020: FoundationDB or: How I Learned to Stop Worrying and Trust the Database

Getting multiple entities to work nicely together is a difficult task. This is true for machines as much as it is true for humans. This is why testing and debugging distributed systems is such a hard task. Even if well known algorithms are used, subtle bugs can introduce catastrophic failures. FoundationDB uses deterministic simulation to test these failures. This is the secret sauce that makes FoundationDB one of the most robust databases on the market. FoundationDB is a distributed key Read More

Quarantine DB Talk 2020: EraDB

This talk is part of the Quarantine Database Tech Talk Seminar Series. Zoom Link: https://cmu.zoom.us/j/562649242 (Password 264771) Read More

Quarantine DB Talk 2020: Datometry Hyper-Q: Virtualizing the World’s Enterprise Data Warehouses

Enterprises worldwide are looking to move their database applications to the cloud. However, conventional migration from an on-premise data warehouse to a cloud-native one is a costly, labor-intensive task, laden with many risks. According to Gartner, the majority of these migrations are late, run over budget, or fail altogether. Datometry has developed a virtualization platform that enables applications written for an on-premises data warehouse to run on a cloud data warehouse — without major rewrites, without rearchitecting. Instead, Datometry Hyper-Q Read More