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0 pointsgrishka3y ago0 comments

A lot of things in a typical social media service can be segmented trivially. The hardest part is the feed because it requires querying many database servers at once, but then it can be cached and served quicker.

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wayfarer2s3y ago

Isn’t cache invalidation the hardest part of the feed? Once a user with millions of followers tweets, doesn’t that essentially invalidate millions of caches? That doesn’t sound like a trivial problem.

naasking3y ago

Because you can't edit tweets, the database is monotonically increasing (append-only) so scaling it isn't that hard. Cache invalidation basically just adds a new item. Deleting a tweet actually would be the harder/more expensive operation, but it's also less common.

grishkaOP3y ago

Editing a tweet is also easy because the feeds would only store its id. You'd only need to invalidate one cache where the tweet object itself is stored.

j / k navigate · click thread line to collapse

0 pointsgrishka3y ago0 comments

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wayfarer2s3y ago

naasking3y ago

grishkaOP3y ago

Editing a tweet is also easy because the feeds would only store its id. You'd only need to invalidate one cache where the tweet object itself is stored.

j / k navigate · click thread line to collapse