asami
minisketch
asami | minisketch | |
---|---|---|
6 | 10 | |
626 | 301 | |
0.0% | - | |
0.0 | 6.3 | |
about 2 years ago | 16 days ago | |
Clojure | C++ | |
Eclipse Public License 1.0 | MIT License |
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asami
- Ask HN: What are some 'cool' but obscure data structures you know about?
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Ask HN: Why are relational DBs are the standard instead of graph-based DBs?
Unlike some other commenters, I agree that graph models are usually a better fit for most data than relational models. There's been some interesting work in recent years developing this idea: in the Clojure world there's Datomic, XTDB, and a host of competitors, all of which build on work from Semantic Web/SPARQL/triplestores and logic programming. Some are even intended to be used as primary datastores: they support some amount of schema and constraints, have well-defined consistency and ACID guarantees, etc. This makes them unlike graph databases like Neo4J and others, which fill an architectural role more like Elasticsearch as a read-optimization tool. Here's an interesting talk making a case for triple-based databases.
- Introduction to the Asami Graph Database
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How to query Datomic, Datascript, Asami, or other graph databases
Despite the documentation that exists, I've heard many people who have been confused about how to query Datomic, Datascript, Asami, or other graph databases. So I've made an attempt at explaining it https://github.com/threatgrid/asami/wiki/Introduction
- Introduction (To Graph Databases)
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Asami
The first Graph implementation for Asami was a simple in-memory data structure, described in my ClojureD talk. The code for this appears in asami.index. This file started much smaller (as referenced above), but has since expanded with the needs extended functionality, such as transactions, and transitive closure operations.
minisketch
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Invertible Bloom Lookup Tables with Less Randomness and Memory
Anyone interested in IBLT with low failure probablity should also be aware of pinsketch and, particularly, our implementation of it: minisketch ( https://github.com/sipa/minisketch/ ).
Our implementation communicates a difference of N b-bit entries with exactly N*b bits with 100% success. The cost for this communications efficiency and reliability is that the decoder takes CPU time quadratic in N, instead of IBLT's linear decoder. However, when N is usually small, if the implementation is fast this can be fine -- especially since you wouldn't normally want to use set recon unless you were communications limited.
Pinsketches and iblt can also be combined-- one can use pinsketches as the cells of an iblt and one can also use a small pinsketch to improve the failure rate of an iblt (since when a correctly sized IBLT fails, it's usually just due to a single undecodable cycle).
- Minisketch: an optimized library for BCH-based set reconciliation
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Peer-to-Peer Encrypted Messaging
Since the protocol appears to use adhoc synchronization, the authors might be interested in https://github.com/sipa/minisketch/ which is a library that implements a data structure (pinsketch) that allows two parties to synchronize their sets of m b-bit elements which differ by c entries using only b*c bits. A naive protocol would use m*b bits instead, which is potentially much larger.
I'd guess that under normal usage the message densities probably don't justify such efficient means-- we developed this library for use in bitcoin targeting rates on the order of a dozen new messages per second and where every participant has many peers with potentially differing sets--, but it's still probably worth being aware of. The pinsketch is always equal or more efficient than a naive approach, but may not be worth the complexity.
The somewhat better known IBLT data structure has constant overheads that make it less efficient than even naive synchronization until the set differences are fairly large (particular when the element hashes are small); so some applications that evaluated and eschewed IBLT might find pinsketch applicable.
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Ask HN: What are some 'cool' but obscure data structures you know about?
I love the set reconciliation structures like the IBLT (Iterative Bloom Lookup Table) and BCH set digests like minisketch.
https://github.com/sipa/minisketch
Lets say you have a set of a billion items. Someone else has mostly the same set but they differ by 10 items. These let you exchange messages that would fit in one UDP packet to reconcile the sets.
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Here is how Ethereum COULD scale without increasing centralisation and without depending on layer two's.
Sipa is working on a better version of that for a while. The technical term is a "set reconciliation protocol", but Bitcoin Core been doing a more basic version of this for a while. Note that the "BCH" there isn't the same as Bcash
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ish: Sketches for Zig
I'd also have to say that Zig is a pretty neat library for this. In order to implement PBS I needed the MiniSketch-library (written in C/C++) and I'll have to say that integrating with it has been a breeze. Some fiddling in build.zig so that I can avoid Makefile, and after that everything has worked amazingly.
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The Pinecone Overlay Network
Networks that need to constrain themselves to limited typologies to avoid traffic magnification do so at the expense of robustness, especially against active attackers that grind their identifiers to gain privileged positions.
Maybe this is a space where efficient reconciliation ( https://github.com/sipa/minisketch/ ) could help-- certainly if the goal were to flood messages to participants reconciliation can give almost optimal communication without compromising robustness.
- Is it any easier to find A, B such that sha256(A) ^ sha256(B) = sha256(C)?
What are some alternatives?
datascript - Immutable database and Datalog query engine for Clojure, ClojureScript and JS
wormhole-william-mobile - End-to-end encrypted file transfer for Android and iOS. A Magic Wormhole Mobile client.
crux - General purpose bitemporal database for SQL, Datalog & graph queries. Backed by @juxt [Moved to: https://github.com/xtdb/xtdb]
ctrie-java - Java implementation of a concurrent trie
datahike - A durable Datalog implementation adaptable for distribution.
t-digest - A new data structure for accurate on-line accumulation of rank-based statistics such as quantiles and trimmed means
datalevin - A simple, fast and versatile Datalog database
tries-T9-Prediction - Its artificial intelligence algorithm of T9 mobile
Apache AGE - Graph database optimized for fast analysis and real-time data processing. It is provided as an extension to PostgreSQL. [Moved to: https://github.com/apache/age]
sdsl-lite - Succinct Data Structure Library 2.0
naga - Datalog based rules engine
ann-benchmarks - Benchmarks of approximate nearest neighbor libraries in Python