Where does the data live, and when is it up to date?
A number that differs from one screen to the next is enough to shake customer trust, and knowing where data lives prevents that kind of incident. This lesson helps a PM identify which store is authoritative for a feature, understand what replicas and synced copies cost, and state the freshness each screen can tolerate.
Lesson objective
By the end of this lesson, you will be able to name the source of truth for each piece of data in a feature, explain what a transaction guarantees and what copies cost (read replicas, caches, synchronized data), and specify the acceptable freshness and the behavior when copies differ.
Topics covered
- source of truth
- database transaction
- read replica
- data consistency
- data freshness
Where it fits
Data, load and dependencies
Where does the data live, what will give way first under load, and what happens when a vendor goes down?
Lessons in this module
- Where does the data live, and when is it up to date? (this lesson)
- Handling the load, finding the bottleneck, deciding on a cache
- Third-party services, composite availability, build or buy
What you will learn in this module
This lesson is part of the course Read and challenge a technical architecture
- Assess data choices (source of truth, transactions, replicas, consistency), scaling and caching, and spot the bottleneck of a user journey.
- Assess dependencies on third-party services (composite availability, degraded mode, vendor lock-in) and a build or buy decision.
Related courses
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- Tech for PMsJuniorSome basics are useful: introductory knowledge of the topic.
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