The retailer that purged its entire cache to fix one price
A mid-size electronics store updated prices hourly. Their deploy script did a full cache flush on every change, so one $20 price edit dumped 90,000 cached pages. The cache went cold, misses spiked, and origin latency in Toronto jumped to 1.6s for ten minutes after each update — twenty-four cold starts a day.
The purge was a sledgehammer where a scalpel belonged.
What we changed: tagged each page with surrogate keys at the edge — product-1042, category-tvs, brand-sony. The price job now purged only the keys touching that SKU, typically 3–12 objects instead of 90,000.
Post-update miss rate fell from 100% to under 0.4%. The hourly latency spikes flattened completely; p95 held at 280ms around the clock. Origin load dropped 22% just from killing the cold-start churn.
The number that mattered: 90,000 purged objects down to 8.
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The retailer that purged its entire cache to fix one price
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