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When imperfect systems are good: Bluesky's lossy timelines

(jazco.dev)
768 points cyndunlop | 2 comments | 19 Feb 25 17:48 UTC | HN request time: 0s | source
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nightpool ◴[19 Feb 25 18:05 UTC] No.43105223[source]▶
Note that all of this reflects design decisions on Bluesky's closed-source "AppView" server—any federated servers interacting with Bluesky would need to construct their own timelines, and do not get the benefit of the work described here.
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xrisk ◴[19 Feb 25 18:08 UTC] No.43105263[source]▶
What reason does Bluesky give for not opening up their AppView code?

Another notable component that is closed source is the discovery feed generator, where at least there is some reason.

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iameli ◴[19 Feb 25 18:26 UTC] No.43105497[source]▶
I asked this and got

> We did a backend rewrite from postgres to scylla and it has a bunch of deployment specific stuff, but is functionally identical to the open source postgres version. Its not really a "v2" in terms of new features, we just made it make use of our hardware really well[1]

[1]: https://bsky.app/profile/iame.li/post/3l7e3jfqit22s

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1. nightpool ◴[19 Feb 25 18:43 UTC] No.43105731{3}[source]▶
Thanks, so are both the Postgres and Scylla versions maintained in terms of new features?

I wasn't aware that AppView v1 was open source, and the most recent info I'm aware of on the topic is https://alice.bsky.sh/post/3laega7icmi2q, https://github.com/bluesky-social/atproto/discussions/2961 and https://docs.bsky.app/docs/advanced-guides/federation-archit..., and everything I've heard about Bluesky was that open source appview is "still coming".

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2. psionides ◴[19 Feb 25 18:55 UTC] No.43105873[source]▶
It's not coming, it never went away… As I understand it, the "business layer" with all the logic is above the data later, shared by the Postgres and Scylla versions, and the data layer just makes queries to the database. I think they are using the Postgres version locally for development.