“I would check whether the event exists, then save it if it doesn’t.”
WHAT TO CLARIFY
Two workers can both pass the existence check. The race between reading and writing is still unresolved.
ONE NEXT ACTION
Trace two concurrent requests. Explain where a unique key and an atomic write prevent duplication, including what happens on retry.
Grounded in this answer · no hiring predictions
FROM PREPARATION TO A NEXT STEP
Turn what you studied into an explanation.
01Choose your scenario and level
A 40-minute Korean system design round using an approved original scenario. No résumé needed.
02Draw and explain
Explain your decisions and failure cases. Respond to the AI’s follow-up questions.
03Use the evidence
Review up to three observed gaps and a next action. Insufficient evidence is clearly marked.
Know what you are getting.
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