All challenges
intermediateReal-World Systems~60 min

WAL & Snapshots

Make your KV store survive restarts. Implement a write-ahead log, replay it to rebuild state, snapshot the dataset to compact the log, and recover cleanly even after a crash mid-write.

6 steps
  1. 1Append-Only Write-Ahead Log
  2. 2Log Set and Delete Operations
  3. 3Replay the Log to Rebuild State
  4. 4A Durable Key-Value Store
  5. 5Snapshots & Compaction
  6. 6Surviving a Crash Mid-Write
Start Step 1