Databases

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In this episode, we are joined by Blake Miner to discuss databases.

Show notes:

• Introduction
  • Blake’s background, what type of work he does, company information, etc.
  • Data has substantial value
• What is a database?
  • General overview - store data, process it, and look it up later
  • Important that data stays intact in the event of a app/system crash, power loss, etc.
  • Important that conflicting concurrent changes are handled appropriately
  • What safety guarantees do I get? -> Transactions / ACID - Atomicity, Consistency, Isolation, Durability
    • atomicity -> abortability guarantee for a group of writes (i.e. upon failure)
    • consistency -> guarantee that certain (app-specific; sometimes database-specific) constraints are not violated
    • isolation -> describes how database handles concurrent edits of the same data. Serializable is the strongest guarantee. Snapshot isolation is very common.
    • durability -> storage guarantee (i.e. upon commit, data has fsync‘ed to disk). Study: SSDs get 1 bad block in first 4 years; disaster could wipe out an entire data center; nothing is perfect.
  • Storage / lookup: Data models / data structures
  • Derived data; caching
  • Concurrency; consistency & isolation
• Reactivity/Realtime
  • tradeoffs between reacting to DB changes vs using a message bus
  • streaming platforms such as NATS Jetstream and Kafka
• SQL
  • Tables and rows -> array of structs
  • SQL -> Declarative query language (query engine determines implementation details at runtime)
  • B-tree Indexes
• NoSQL Databases
  • “NoSQL” -> a marketing term
• Redis
  • Data structure store
  • In-memory vs. disk-based
• Embedded databases (i.e. API vs. commands over TCP)
• Designing Data-Intensive Applications by Martin Kleppmann. Blake recommends this book.

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