Ghosts of Snapshots Past

A easy AI Coding interview practice problem on DataDriven. Write and execute real ai coding code with instant grading.

Domain

AI Coding

Difficulty

easy

Seniority

L4

Problem

Yesterday a bad backfill wrote 2M corrupt rows into events_iceberg. We rolled back to the prior snapshot. Now an analyst's AS OF (timestamp) query for a window two days before the rollback is also returning the corrupt rows. Reproduce by running tests/test_time_travel.py. The bug is in how our reader resolves a snapshot for a timestamp; fix it so AS OF queries reflect what was visible at that time.

Summary

The past keeps rewriting itself.

Practice This Problem

Solve this AI Coding problem with real code execution. DataDriven runs your solution and grades it automatically.