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While this loads — quick one
Every subscriber must get each event. A queue, or pub/sub?
Message queueorPub/Sub
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While this loads — quick one
Every subscriber must get each event. A queue, or pub/sub?
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While this loads — quick one
Every subscriber must get each event. A queue, or pub/sub?
A social app lets people follow each other and post short updates, some with photos. Opening the app shows a home feed: the newest posts from everyone you follow, and it must appear in well under a secondThis asks forA feed that is already assembled when it is asked for, held in memory., because people open it dozens of times a day. Reads outnumber posts by about a hundred to oneThis asks forDo the expensive work once per post, not once per read.. When someone posts, it is fine if followers see it a few seconds later, but the post itself must never be lostThis asks forA durable store the post is written to first., and the person posting must not wait while the app works out who should see itThis asks forHand the fan-out to a line of work done in the background.. Photos are large and are viewed far more often than they are uploaded, by people all over the worldThis asks forServe photos from locations near each viewer..