Data Migration and Consistency Questions
Plan and execute data migrations while preserving correctness and availability. Topics include zero downtime migration techniques, schema evolution patterns, backward and forward compatibility, dual writes and shadow writes, incremental and bulk migration strategies, data validation and reconciliation, canary migrations, rollbacks and fallback plans, and how to minimize user impact during transitions. Understand trade offs between consistency and speed of migration and techniques to detect and correct drift after migration.
EasyTechnical
0 practiced
Explain forward and backward compatibility for database schema evolution. For each of these schema changes, explain whether they are forward- and/or backward-compatible and why: (a) adding a nullable column, (b) renaming a column, (c) changing an INT to BIGINT, (d) splitting a full_name column into first_name and last_name.
EasyTechnical
0 practiced
Describe the difference between dual-write and shadow-write migration patterns. For a payment-processing system with strict correctness requirements, when would you prefer one over the other? List key pitfalls to avoid for each approach.
HardTechnical
0 practiced
Design a reconciliation algorithm/system that detects and resolves conflicts between source and target when the migration included non-deterministic transformations (e.g., derived scores using external ML services). Describe how to identify conflicts, rank corrective actions (auto-fix, manual review), and maintain auditability.
HardBehavioral
0 practiced
Describe a time when a migration you were responsible for encountered a major failure or data incident. How did you lead the team through triage, client communication, remediation, and the post-mortem? Emphasize decision-making, communication cadence, and lessons you enforced afterward.
MediumTechnical
0 practiced
You need to migrate parent (accounts) and child (transactions) tables in batches. Describe an algorithm to migrate in batches while preserving referential integrity and minimizing locking, including how you handle concurrent writes and foreign-key constraints during the migration.
Unlock Full Question Bank
Get access to hundreds of Data Migration and Consistency interview questions and detailed answers.
Sign in to ContinueJoin thousands of developers preparing for their dream job.