Distributed Systems · core
Distributed Workflows & Temporal
Durable execution, event histories, deterministic replay, activities, retries, timers, and long-running workflows.
Mental model
A durable workflow persists decisions as history and replays deterministic code after failure. Side effects live in retryable activities with explicit idempotency.
How to study Distributed Workflows & Temporal
Begin by restating the mental model in your own words, then connect it to a concrete system you have built or operated. Name the mechanism, the constraint it addresses, and the trade-off it introduces. Use Netherite: Efficient Execution of Serverless Workflows (PVLDB 15), Reliable Actors with Retry Orchestration, Workflows, a New Abstraction for Distributed Systems — Dominik Tornow (Strange Loop 2022) to check details, but close the source before writing your explanation. Retrieval is the learning step; rereading is only preparation.
Next, compare Distributed Workflows & Temporal with Distributed Infra, Distributed Failure Recovery. Ask what changes in correctness, latency, resource use, operability, and failure recovery. Complete Design exercise: Distributed Workflows & Temporal and preserve the command, input, output, and one failed attempt as evidence. Finish by explaining the idea without jargon to someone who has not studied the track.
Proof of understanding
- Explain the mechanism from first principles and identify the state it reads or changes.
- Give one situation where the concept is the right choice and one where it is not.
- Predict a realistic failure mode before running the drill, then compare the prediction with evidence.
- Connect the result to a roadmap or build artifact instead of treating the concept as isolated trivia.
Learn from primary sources
- Netherite: Efficient Execution of Serverless Workflows (PVLDB 15) (doc)
- Reliable Actors with Retry Orchestration (doc)
- Workflows, a New Abstraction for Distributed Systems — Dominik Tornow (Strange Loop 2022) (video)
- Durable Functions: Semantics for Stateful Serverless (OOPSLA '21) (paper)
- Temporal Documentation (doc)
Practice and explain it back
Design exercise: Distributed Workflows & Temporal
Durable execution, event histories, deterministic replay, activities, retries, timers, and long-running workflows. Implement designOutline() returning non-empty values for: workflowHistory, deterministicReplay, activityIdempotency. Each value must name a concrete mechanism or decision.
Expected evidence: A design outline with workflowHistory, deterministicReplay, activityIdempotency plus an explicit failure mode or trade-off.
Open the interactive drill →Review prompts
- Durable execution replays workflow code after a crash. What does that require of the code you write?
Build evidence
Synthesize: Distributed Systems
Reason about coordination, data placement, logs, durable workflows, consistency, and recovery under partial failure. Produce one working system, benchmark, or evidence-backed design that integrates the path.
- Implements or precisely models the core mechanisms from all three milestones
- Includes at least one injected failure or adversarial case and demonstrates recovery
- Reports quality, latency, resource, reliability, or usability measurements relevant to the domain
- Ships a concise architecture note explaining decisions, trade-offs, and remaining risks