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.
MediumSystem Design
20 practiced
Design a schema evolution pattern that uses feature flags to deploy and roll out non-breaking schema changes across producers and consumers. Include how you manage flag lifecycle, data backfills, read-compatibility, and eventual removal of legacy code.
EasyTechnical
24 practiced
What is Change Data Capture (CDC) and how is it used in incremental migrations? Describe the main CDC approaches (log-based, trigger-based, timestamp-based) and one advantage and disadvantage of each for migrating an OLTP database.
HardTechnical
17 practiced
Compare parity/checksum approaches vs cryptographic hashes (e.g., MD5, SHA-256) for validating large datasets during migration. Discuss collision risk, compute cost, incremental validation, and scenarios where a probabilistic structure (e.g., Bloom filter) is preferable.
MediumTechnical
22 practiced
Explain how snapshot isolation and consistent reads are useful during a migration. Describe a concrete approach to take a consistent snapshot from an OLTP system to seed a target DB while applying streaming changes (CDC) to maintain correctness.
EasyBehavioral
21 practiced
Tell me about a time you helped design or deliver a data migration (any scale). Use the STAR method: Situation, Task, Action, Result. Focus on how you translated business requirements into technical constraints, managed risk, and handled a complication during execution.
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.