Performance and scaling interview questions
Load balancing, tail latency, Little's law, profiling, scaling up and out, read replicas, batching, compression, autoscaling, load testing, hot spots and memory.
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Flashcards · 17
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Quick facts
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Little's law
L = λW: items in a stable system equal arrival rate times time in the system.
Mean vs tail
95 requests at 20 ms and 5 at 900 ms average 64 ms, while p99 is 900 ms.
COPY
PostgreSQL's bulk-load command; psycopg 3 exposes it as
cursor.copy().lru_cache default
functools.lru_cache keeps 128 entries by default; maxsize=None is unbounded.
Coordinated omission
Load tools that wait for each response before sending the next under-report tail latency.
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Sources: Topic outline informed by System Design Primer by Donne Martin and the Zalando RESTful API Guidelines, both licensed under CC BY 4.0. Every question and answer is written by Best Latest Apps. Credits and license