Search Indexing Service  ·  View 05 of 21  ·  People and journeys

Journey — A Merchant Publishes a Change

The one user who checks immediately, and why they do not get to set the freshness budget for 80 million documents.

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Merchant one shop, phone Goal — Drop the price before the evening rush and know it took Trigger — Quiet hour, stock to move Done when — Searches their own shop, sees the new price 1 · Edit merchant console 2 · Save 3 · Check ◆ moment of truth 4 · Wait 5 · Believe What they do Changes price Taps save Searches own shop Refreshes Stops checking What answers Merchant service Change log commit Owner-write overlay Fast lane writer idx_v41 How it feels Confident Unsure Distrusts Where it hurts Old price still shown No idea how long What the design owes Ack on durable commit Read-your-writes ≤ 1 s Freshness in response Fast lane, not a rebuild Journey — A Merchant Publishes a Change The one merchant who checks sets the read-your-writes requirement — not the freshness budget for 80 M documents. v 1.0 · owner Data Platform Architecture

What the trough tells the architecture

  • The dip is at 'check', seconds after the save: the merchant searches their own shop and sees the old price. Read-your-writes for the owner is a 1-second requirement.
  • It is answered by an overlay in the query service reading a short-TTL recent-writes table — not by making the index itself that fresh, which would cost the platform its write-path economics.
  • The second dip, 'wait', is an information failure rather than a latency one: the response carries its observed freshness so the console can say how long.

Decisions

  • The source is acknowledged when the change is durable in the log, not when it is searchable — which is what keeps the accept path at a 50 ms p99.
  • The overlay applies the owner's own pending changes only. It is not a general consistency mechanism and is not offered to consumer queries.
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Solution Architecture v1.0 · Amazon Web Services · Data Platform Architecture · 2026-1005-journey-publish-a-change