OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) · HackerPapers discussions

OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) — mentioned by mweidner

Thu, 21 May 2026 21:29:21 GMT

For values that don't have a natural merge function (or where you don't want to bother writing one), would it make sense to sync update logs instead? That is: - The synced value is a history of client updates, sorted in some eventually consistent order (e.g. by hybrid logical clocks). Merging takes the union of the update sets. - The user-visible value is the result of processing these updates in order, using arbitrary contract code. This is overkill for simple last-writer-wins values, but it lets you support fairly general data types & arbitrary update functions, including ones that preserve…

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OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) — mentioned by rkallos

Wed, 23 Jun 2021 19:43:59 GMT

Definitely a tricky problem for CRDTs. A possible solution is outlined in the OpSets paper; https://arxiv.org/abs/1805.04263 I hope that there are existing implementations of OpSets that perform well. I find the solution laid out in that paper to be really elegant and beautiful.

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OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) — mentioned by migueloller

Wed, 09 Dec 2020 00:41:48 GMT

Kleppmann, et al.'s paper on OpSets [1], a specification for building CRDTs with support for an atomic tree move operation, was the best one for me. Automerge [2] implements a variant of this. [1] https://arxiv.org/abs/1805.04263 [2] https://github.com/automerge/automerge

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OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) — mentioned by haadcode

Mon, 20 Apr 2020 13:07:30 GMT

> How do you know that? It's not inferrable from the DAG. Is sequencing also provided "a layer up"? I jumped the gun there and made an assumption that the value of a node is the LWW ordering :) Ok, so without that assumption, the DAG 1 --> 2 --> 3 --> 4 `--> 5 --> 6 ...are the values of the operations that the DAG represents, ie. values of a key, so we need to look at the Lamport clocks (or Merkle Clocks when the operations are hashed as a merkle dag) of each operation, represented here as ((ts, id), key, value): ((0, x), a, 1) --> ((1, x), a, 2) --> ((2, x), a, 3) --> ((3, x), a, 4) `-->…

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OpSets: Sequential Specifications for Replicated Datatypes (Extended Version) — mentioned by migueloller

Tue, 14 Jan 2020 00:29:18 GMT

I’ve been doing a pretty deep dive on CRDTs and OTs to get the right user experience for our collaborative website builder[1]. I’m still not done with the implementation and subsequent testing (i.e., splitting text nodes, as mentioned in the post). But the core algorithm behind Automerge[2], formalized in the OpSets paper[3] is extremely promising. A good example of its power is the ability to do an atomic tree “move”, whilst preserving strong eventual consistency. I'm so glad to see that the HN community cares about this problem space. Maybe I should finally write that blog post on CRDTs and…

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