Day4
60-day SSE plan
Logger Service • E-commerce Order Service • Graph Topological Sort • Tech: Solr
Algorithm
DSA
Graph Topological Sort — Course Schedule (LC 207)
Detect if you can finish all courses given prerequisites via Kahn's or DFS.
Example
Input: prerequisites edges → Output: true/false
Where it shows up
Dependency resolution, job scheduling, build pipelines.
References
Low-level design
LLD
Logger Service
Requirements
- Append logs concurrently; rotate file on size/time.
Expectations
- Thread-safe singleton; async queue & writer thread.
- Demonstrate rotation strategy.
Where it shows up
Service logging, audit trails, observability.
References
High-level design
HLD
E-commerce Order Service
Requirements
- Create/manage orders; inventory reserve; payment auth; status events.
Expectations
- Saga orchestration, outbox pattern, idempotency design.
- APIs, schema, eventing & retries.
Where it shows up
Retail marketplaces, online stores.
References
Today's deep-dive
Tech
Solr
Run Solr in Docker; create a core; index sample JSON; test analyzers & facets.
Where it shows up
Search engines, e-commerce product search, log analytics, and any system requiring fast, flexible text search and faceting.
References