Stories with Tag Raft

• Show HN: A Database Written in Golang

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  Posted: 2025-02-26 14:28:26

  Verbose tl;dr

  AtomixDB is a new open-source, embedded, distributed SQL database written in Go. It aims for high availability and fault tolerance using a Raft consensus algorithm. The project features a SQL-like query language, support for transactions, and a focus on horizontal scalability. It's intended to be embedded directly into applications written in Go, offering a lightweight and performant database solution without external dependencies.

  Sahil Bansal has introduced AtomixDB, a novel database management system implemented entirely in the Go programming language. This project aims to provide a performant and robust database solution, leveraging the strengths of Go, such as its concurrency features and efficient garbage collection. AtomixDB is designed with a focus on simplicity and ease of use, aiming to be a practical choice for various applications.

  While the full feature set is still under development, AtomixDB currently supports core database functionalities, including data persistence and retrieval. It employs a key-value store architecture, enabling efficient storage and access of data through unique keys. The database utilizes an on-disk storage mechanism, ensuring data durability across sessions.

  The project emphasizes a clean and modular codebase, promoting maintainability and extensibility. The choice of Go contributes to this by offering a statically typed language with a relatively simple syntax and a rich standard library. AtomixDB's implementation details suggest a commitment to performance optimization, although specific benchmarks are not yet available.

  Furthermore, the project is open-source, encouraging community involvement and contributions. This fosters transparency and allows for collaborative development, potentially leading to a more robust and feature-rich database system over time. The project's current stage suggests it is actively being developed, with future plans likely encompassing expanded functionalities and performance improvements. While the current implementation provides a foundational key-value store, the project leaves room for potential exploration of other database paradigms in the future.

  • Golang
  • Database
  • distributed systems
  • key-value store
  • Raft
  • Show HN
  • Open Source
  • atomixdb
  • fault tolerance
  • Go

  Summary of Comments ( 24 )
  https://news.ycombinator.com/item?id=43183891

  Verbose tl;dr

  HN commenters generally expressed interest in AtomixDB, praising its clean Golang implementation and the choice to avoid Raft. Several questioned the performance implications of using gRPC for inter-node communication, particularly for write-heavy workloads. Some users suggested benchmarks comparing AtomixDB to established databases like etcd or FoundationDB would be beneficial. The project's novelty and apparent simplicity were seen as positive aspects, but the lack of real-world testing and operational experience was noted as a potential concern. There was some discussion around the chosen consensus protocol and its trade-offs compared to Raft.

  The Hacker News post titled "Show HN: A Database Written in Golang" (linking to the AtomixDB GitHub repository) has generated several comments, offering a mix of praise, critique, and inquiries.

  Several commenters express initial positive impressions, appreciating the project's ambition and the apparent clean codebase. One commenter highlights the clear documentation as a strong point, making the project approachable for those wanting to understand its inner workings. Another emphasizes the value of having a learning-oriented database project in Go, contrasting it with the complexity of established databases, and thus making it a good resource for educational purposes.

  However, some commenters raise concerns and offer constructive criticism. A recurring theme is the lack of performance comparisons. Commenters question how AtomixDB stacks up against existing database solutions, emphasizing that benchmarks are essential for assessing the project's viability. They suggest comparing it with established Go-based databases like BadgerDB and BoltDB, or even more broadly with databases like SQLite. The absence of this data leaves potential users unsure of AtomixDB's practical applications.

  Another point of discussion revolves around the choice of using Raft for distributed consensus. While acknowledging Raft's robustness, some commenters inquire about the performance implications and suggest exploring alternative consensus algorithms that might be more efficient for certain workloads. Related to this, questions are raised about the single-leader limitation in the current Raft implementation.

  Further points of interest include questions regarding the project's maturity level and future plans. Commenters inquire about the roadmap, planned features, and the author's long-term vision for the database. There's also a discussion around potential use cases, with commenters speculating about scenarios where AtomixDB could be a good fit, such as embedded systems or specific niche applications.

  Finally, some commenters offer practical advice and suggestions for improvement. One commenter points out the importance of testing and suggests incorporating property-based testing to ensure correctness. Another advises considering compatibility with WireGuard for secure communication.

  In summary, the comments reflect a genuine interest in the AtomixDB project, appreciating the effort while also highlighting key areas for improvement, particularly regarding performance evaluation and providing a clearer picture of the project’s future direction.

• How rqlite is tested

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  Posted: 2025-01-14 20:21:47

  Verbose tl;dr

  rqlite's testing strategy employs a multi-layered approach. Unit tests cover individual components and functions. Integration tests, leveraging Docker Compose, verify interactions between rqlite nodes in various cluster configurations. Property-based tests, using Hypothesis, automatically generate and run diverse test cases to uncover unexpected edge cases and ensure data integrity. Finally, end-to-end tests simulate real-world scenarios, including node failures and network partitions, focusing on cluster stability and recovery mechanisms. This comprehensive testing regime aims to guarantee rqlite's reliability and robustness across diverse operating environments.

  Philip O'Toole's blog post, "How rqlite is tested," provides a comprehensive overview of the testing strategy employed for rqlite, a lightweight, distributed relational database built on SQLite. The post emphasizes the critical role of testing in ensuring the correctness and reliability of a distributed system like rqlite, which faces complex challenges related to concurrency, network partitions, and data consistency.

  The testing approach is multifaceted, encompassing various levels and types of tests. Unit tests, written in Go, form the foundation, targeting individual functions and components in isolation. These tests leverage mocking extensively to simulate dependencies and isolate the units under test.

  Beyond unit tests, rqlite employs integration tests that assess the interaction between different modules and components. These tests verify that the system functions correctly as a whole, covering areas like data replication and query execution. A crucial aspect of these integration tests is the utilization of a realistic testing environment. Rather than mocking external services, rqlite's integration tests spin up actual instances of the database, mimicking real-world deployments. This approach helps uncover subtle bugs that might not be apparent in isolated unit tests.

  The post highlights the use of randomized testing as a core technique for uncovering hard-to-find concurrency bugs. By introducing randomness into test execution, such as varying the order of operations or simulating network delays, the tests explore a wider range of execution paths and increase the likelihood of exposing race conditions and other concurrency issues. This is particularly important for a distributed system like rqlite where concurrent access to data is a common occurrence.

  Furthermore, the blog post discusses property-based testing, a powerful technique that goes beyond traditional example-based testing. Instead of testing specific input-output pairs, property-based tests define properties that should hold true for a range of inputs. The testing framework then automatically generates a diverse set of inputs and checks if the defined properties hold for each input. In the case of rqlite, this approach is used to verify fundamental properties of the database, such as data consistency across replicas.

  Finally, the post emphasizes the importance of end-to-end testing, which focuses on verifying the complete user workflow. These tests simulate real-world usage scenarios and ensure that the system functions correctly from the user's perspective. rqlite's end-to-end tests cover various aspects of the system, including client interactions, data import/export, and cluster management.

  In summary, rqlite's testing strategy combines different testing methodologies, from fine-grained unit tests to comprehensive end-to-end tests, with a focus on randomized and property-based testing to address the specific challenges of distributed systems. This rigorous approach aims to provide a high degree of confidence in the correctness and stability of rqlite.

  • rqlite
  • testing
  • Database
  • sqlite
  • distributed systems
  • fault tolerance
  • integration testing
  • unit testing
  • Go
  • raft consensus
  • replication
  • data consistency
  • software testing
  • database testing
  • Raft
  • Go programming
  • distributed databases
  • distributed database

  Summary of Comments ( 40 )
  https://news.ycombinator.com/item?id=42703282

  Verbose tl;dr

  HN commenters generally praised the rqlite testing approach for its simplicity and reliance on real-world SQLite. Several noted the clever use of Docker to orchestrate a realistic distributed environment for testing. Some questioned the level of test coverage, particularly around edge cases and failure scenarios, and suggested adding property-based testing. Others discussed the benefits and drawbacks of integration testing versus unit testing in this context, with some advocating for a more balanced approach. The author of rqlite also participated, responding to questions and clarifying details about the testing strategy and future plans. One commenter highlighted the educational value of the article, appreciating its clear explanation of the testing process.

  The Hacker News post "How rqlite is tested" (https://news.ycombinator.com/item?id=42703282) has several comments discussing the testing strategies employed by rqlite, a lightweight, distributed relational database built on SQLite.

  Several commenters focus on the trade-offs between using SQLite for a distributed system and the benefits of ease of use and understanding it provides. One commenter points out the inherent difficulty in testing distributed systems, praising the author for focusing on realistically simulating network partitions and other failure scenarios. They highlight the importance of this approach, especially given that SQLite wasn't designed for distributed environments. Another echoes this sentiment, emphasizing the cleverness of building a distributed system on top of a single-node database, while acknowledging the challenges in ensuring data consistency across nodes.

  A separate thread discusses the broader challenges of testing distributed databases in general, with one commenter noting the complexity introduced by Jepsen tests. While acknowledging the value of Jepsen, they suggest that its complexity can sometimes overshadow the core functionality of the database being tested. This commenter expresses appreciation for the simplicity and transparency of rqlite's testing approach.

  One commenter questions the use of Go's built-in testing framework for integration tests, suggesting that a dedicated testing framework might offer better organization and reporting. Another commenter clarifies that while the behavior of a single node is easier to predict and test, the interactions between nodes in a distributed setup introduce far more complexity and potential for unpredictable behavior, hence the focus on comprehensive integration tests.

  The concept of "dogfooding," or using one's own product for internal operations, is also brought up. A commenter inquires whether rqlite is used within the author's company, Fly.io, receiving confirmation that it is indeed used for internal tooling. This point underscores the practical application and real-world testing that rqlite undergoes.

  A final point of discussion revolves around the choice of SQLite as the foundational database. Commenters acknowledge the limitations of SQLite in a distributed context but also recognize the strategic decision to leverage its simplicity and familiarity, particularly for applications where high write throughput isn't a primary requirement.