5–8 years · Senior — Java · Spring Boot · REST APIs · JPA / Hibernate · SQL · Microservices
Reviews API response times and identifies slow endpoints using metrics; checks for heavy payloads and considers pagination or reducing data size; assesses the complexity of business logic in controllers; investigates caching strategies for frequent requests; suggests implementing rate limiting and throttling to manage load.
If pagination is implemented but performance issues persist, what further steps can be taken?
Checks service status and health endpoints; implements a circuit breaker pattern to avoid cascading failures; queues requests for later processing if possible; communicates incidents to stakeholders and sets expectations; evaluates fallback mechanisms or alternative services.
How would you ensure that the circuit breaker doesn’t lead to stale data being served?
Plans a phased migration approach to reduce load; uses shadow reads to compare old and new datasets; implements change data capture for ongoing changes during migration; sets up rollback procedures in case of issues; ensures thorough testing of migration scripts.
If the migration process encounters unexpected performance degradation, how would you adjust your approach?
Describes the technology or framework being migrated from and to; discusses specific challenges encountered such as compatibility issues or team resistance; details the strategy used for the migration and any rollback plans; explains the impact on the business and users; shares outcomes and follow-up actions.
How did you measure the success of the migration?
Monitors service metrics like CPU, memory, and response times; checks for bottlenecks in API calls and service dependencies; verifies whether the service is stateless; assesses whether proper load balancing and caching are implemented; prioritises optimising database access patterns.
If you find that the database is a bottleneck, what strategies can you employ to alleviate the pressure?
Communicates deprecation timeline to users through documentation and headers; implements a graceful transition period with both versions running; monitors usage of the old API; provides support and migration guides for users; sets a hard deadline for the removal of the old version.
If users refuse to migrate, how do you balance support for the old version with the need to advance the codebase?
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