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"Turning the database inside out with Apache Samza" by Martin Kleppmann

Strange Loop Conference · talk · Watch on YouTube

Databases & storageDistributed systems

What it is

Martin Kleppmann argues that databases are global shared mutable state and proposes treating them as an ever-growing log of immutable facts. Derived data such as caches, indexes and views is then built by stream processors like Apache Samza. The talk draws on Kafka and LinkedIn's experience with commit logs.

Why Hacker News recommends it

Commenters repeatedly cite it as the talk that reframed how they think about caching, derived data and event sourcing.

  • 9 people recommended it
  • 9 different months
  • 5 strong recommendations
  • first 2015, last 2025

What HN commenters said

  1. “Here's an excellent talk that provides some context to the Confluent article”

    Simplifying database-cache interactions by thinking in streams of derived data

    btown, 2015-04 · Strong recommendation · in “How Sift Science Rebuilt Its App on React and DropWizard”

  2. “I can highly recommend Martin Kleppmann”

    Explains the log as the core of databases

    lbradstreet, 2018-05 · Strong recommendation · in “GCP and Confluent partner to deliver a managed Apache Kafka service”

  3. “This talk on Apache Samza completely changed how I think about caching and derived data in general”

    Changed how commenter thinks about caching and derived data

    chamomeal, 2025-08 · Strong recommendation · in “Replacing a cache service with a database”

  4. “Samza's author really opened my mind related to how useful stream process is to high performance data processing”

    Shows how useful stream processing is for data processing

    felipesabino, 2015-04 · Recommendation · in “Real-Time Full-Text Search with Luwak and Samza”

  5. “talk by Martin Kleppmann is pretty good too”

    Modern concrete example of event sourcing ideas

    pramodliv1, 2016-04 · Recommendation · in “GraphQL-enabled event sourcing engine”

  6. “I think this video[1] does a nice job of talking about stream processing as a programming architecture.”

    Stream processing as a programming architecture linked to messaging

    z1mm32m4n, 2016-06 · Recommendation · in “Alan Kay on the misunderstanding of OOP (1998)”

  7. “a good starter to for knowing how to use a Streaming Store like Kafka as DB”

    Starter for using a streaming store like Kafka as a database

    je42, 2020-12 · Recommendation · in “Kafka Is Not a Database”

  8. “Martin's talk validated many of my obsessive-compulsive insecurities about data.”

    Inspired the commenter's adoption of event sourcing

    dmitryminkovsky, 2021-09 · Recommendation · in “The Reactive Monolith – How to Move from CRUD to Event Sourcing”

Excerpts from Hacker News comments, linked to the originals. Summaries and labels were written by a language model from those comments.

Topics: apache samza, kafka, event sourcing, immutable data, commit log, derived data

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