Persistence

Caching and Persistence

When and how to cache a Spark DataFrame to avoid recomputation, the tradeoffs between storage levels, and the pitfalls of over-caching or forgetting to unpersi…

Message Durability and Persistence

Learn how RabbitMQ keeps queues and messages alive across broker restarts using durable queues, persistent delivery mode, and the trade-offs involved in guaran…

Redis Data Persistence: RDB and AOF

How Redis persists in-memory data to disk using RDB snapshots and the AOF log, and how to choose (or combine) the right strategy for your workload.

Redis Persistence Tradeoffs

A practical comparison of RDB snapshots and AOF logging in Redis, and how to choose or combine them based on your durability and performance needs.

UserDefaults and Persistence

Learn when and how to use UserDefaults for lightweight app settings and small persisted values, and how it compares to other persistence options.

What is the Repository Pattern?

The Repository pattern is a design pattern that mediates between the domain/business logic and the data mapping layer, exposing a collection-like interface (ad…

What is the Unit of Work Pattern?

The Unit of Work pattern tracks a set of business object changes made during a single logical operation and coordinates writing them out as one atomic transact…

What is the Active Record Pattern?

Active Record is a design pattern where an object wraps a row of a database table (or view), encapsulating both the data and the persistence logic (save, delet…

Active Record vs Repository Pattern

Active Record bundles data and persistence logic (save, find, delete) directly onto the domain object itself, while the Repository pattern separates persistenc…

What is the DAO Pattern?

The DAO (Data Access Object) pattern is a structural pattern that isolates all persistence-related code — SQL statements, connection handling, and result-set m…