Hard Design: E-Commerce System (Amazon)

What approach prevents a user from seeing stale inventory counts in the product listing?

— Tests your understanding of this concept.

Answer Options

A Always query live inventory DB for every page load

B Cache inventory with short TTL (30 seconds); show 'In Stock' vs 'Out of Stock' not exact count

C Never show inventory count

D Refresh inventory count only on checkout

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This question is from the Design: E-Commerce System (Amazon) topic (System Design Cases).

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