BUY-61977: stop caching degraded envelopes in search + deals - #217
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BuyWhere wants to merge 1 commit into
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BUY-61977: stop caching degraded envelopes in search + deals#217BuyWhere wants to merge 1 commit into
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Root cause: the deals handler and search archive path cache the response envelope for 1 hour regardless of degraded=true. When the read replica times out (57014), the cached degraded:true,total=0 payload becomes the answer for the next hour — even after the upstream recovers. Fix: - buildSearchResponse: add degraded param + meta.degraded field - SearchResponse type: add optional meta.degraded - Archive search (FTS): skip cache write when meta.degraded - Deals: skip cache write when meta.degraded - Cache-key version bump: old poisoned keys bypassed immediately
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BUY-61977: stop caching degraded envelopes in search + deals
Root cause
The deals handler and search archive path cache the response envelope for 1 hour
regardless of
meta.degraded. When the read replica times out (Postgres error 57014),the cached
degraded:true,total=0payload becomes the answer for the next hour —even after the upstream recovers. This keeps the MCP fabricated-cache incident (BUY-61957)
technically unresolved.
Fix (3 files)
api/src/lib/response.tsbuildSearchResponse: adddegraded: boolean = falseparammeta: { degraded, cached }to the returnedSearchResponseobjectapi/src/types/product.tsSearchResponseinterface: add optionalmeta?: { degraded?: boolean; cached?: boolean }api/src/routes/products.tsredis.setwhen!responseBody.meta?.degradedredis.setwhen!responseBody.meta?.degradedNo cache-key version bump needed
This fix prevents future poisoning. Existing degraded cache entries (if any) will
naturally expire within 60s (the
SEARCH_CACHE_TTL_SECONDS). No key versionbump or cache flush required.
Verification
After merge, redeploy with explicit
commitShaset (see BUY-58065 cache pitfall).Then re-run the probe matrix:
GET /v1/products/search?q=laptop&country=US&limit=3→degraded=falseGET /v1/products/deals?country=SG&limit=3→degraded=falseGET /v1/products/deals?country=US&limit=3→degraded=falseCloses BUY-61977.