2–5 years · Mid — Python · Django / Flask / FastAPI · REST APIs · SQL · Celery · Testing
Identifies integration and end-to-end tests required for complex interactions; uses mocking to isolate components during tests; implements test cases that cover edge cases and user scenarios; evaluates test coverage tools to identify gaps; incorporates Continuous Integration to run tests automatically.
What role does test-driven development play in this process?
Implements a fallback mechanism for local authentication; logs the failure rate for analysis; notifies users of the issue through a status page; escalates to appropriate teams for third-party resolution; assesses impact on user experience.
What long-term strategies would you implement to mitigate the impact of similar outages in the future?
Details the specific design choice and the problem it aimed to solve; explains the reasons for the design at the time; describes how the issue was discovered and its effect on the service; outlines the adjustments made post-issue; avoids attributing blame to team dynamics.
What alternative designs did you consider at the time?
Analyses the execution plan for expensive operations; checks for missing indexes on frequently queried fields; evaluates if the selected columns are necessary or if projections can reduce the load; considers pagination to limit returned records; reviews the database schema for normalization issues.
What impact does denormalisation have on query performance?
Checks recent code changes related to data retrieval; examines user permissions and query filters; reviews error logs for access patterns; verifies database migrations for completeness; considers user session states affecting access.
You discover the regression relates to a change in the data model. How do you ensure this doesn’t happen again in future deployments?
Identifies I/O-bound tasks as the source of bottlenecks; evaluates the Global Interpreter Lock (GIL) impact on CPU-bound tasks; considers the overhead of thread management; assesses whether using async would simplify control flow; mentions potential libraries like asyncio or aiohttp for handling async tasks.
What specific scenarios still benefit from threads over async?
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