Before I dive into gRPC, let me briefly explain the reasons for having gRPC. It is all about simplifying the communication between microservices and normal services. Normally, communication is done through implementing APIs to communicate between nodes and services. Unfortunately, APIs are hard because you need to specify the communication…

In this post, I will review and summarize the Polyjuice paper by Jiachen Wang and others, in OSDI’21. This paper is about tuning the knobs of concurrency control in in-memory database systems by using machine learning techniques to improve system performance. Before taking a deep dive into the review, I…

This paper proposed an implementation and evaluation of a dynamic timestamp allocation algorithm called MaaT. MaaT is a variant of the optimistic concurrency control algorithm. The main idea is to provide a range of timestamps for each transaction instead of a fixed timestamp in CockroachDB. The purpose of MaaT is…

Recently, I came across Mike Kowalski’s talk at the Hydra conference 2021 about the CAP theorem. I liked the talk because it was easy to understand given that I know what the CAP theorem is all about. I also read a Critique of the CAP theorem paper by Martin Kleppmann…

The top layer of cockroach DB is called the SQL layer. The SQL layer takes SQL statements from the application by providing SQL API and converts them into low-level read-and-write requests to the underlined key-value store. The key-value pairs are passed to the transaction layer. …

Cockroach DB was developed in 2015 by Ben Darnell and other two engineers. The Cockroach is named after a resilient species. The purpose of cockroach DB is to create an open-source version of Google Spanner, a distributed SQL DB. As you may know, traditional SQL fails to maintain scalability and…

This is a simple note on what is the database system. From a high level, the database is an organized collection of structured data that is typically stored electronically in a storage medium. Application developers suppose to write software to handle and maintain the data in the storage medium. This…

In this first part post, I will summarize the CockroachDB system. In the following posts, I will go deep into the system’s architecture layers. In the database world, there are many classes. Here I will just mention the relevant classes to the CockroachDB such as Relational, NoSQL, and NewSQL. Many…

Concurrency Control is the management of concurrently executing transactions. A transaction is a sequence of a write and a read on the database. Hence, the database only sees the read and write operations. The goal of concurrency control is to deal with interleaving transactions. Let me show you in the…