tantivy
Folly
tantivy | Folly | |
---|---|---|
48 | 90 | |
9,955 | 27,118 | |
2.2% | 0.6% | |
9.1 | 9.8 | |
7 days ago | 6 days ago | |
Rust | C++ | |
MIT License | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
tantivy
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SeekStorm VS tantivy - a user suggested alternative
2 projects | 22 Mar 2024
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What is Hybrid Search?
Tantivy - a full-text indexing library written in Rust. Has a great performance and featureset.
- Tantivy – Fast, OSS full-text search library in Rust
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RAG Using Unstructured Data and Role of Knowledge Graphs
By this I presume you mean build a search index that can retrieve results based on keywords? I know certain databases use Lucene to build a keyword-based index on top of unstructured blobs of data. Another alternative is to use Tantivy (https://github.com/quickwit-oss/tantivy), a Rust version of Lucene, if building search indices via Java isn't your cup of tea :)
Both libraries offer multilingual support for keywords, I believe, so that's a benefit to vector search where multilingual embedding models are rather expensive.
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Show HN: Quickwit – OSS Alternative to Elasticsearch, Splunk, Datadog
We also implemented our schemaless columnar storage optimized for object storage.
The inverted index and columnar storage are part of tantivy [0], which is the fastest search library out there. We maintain it and we decided to build the distributed engine on top of it.
[0] tantivy github repo: https://github.com/quickwit-oss/tantivy
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Pg_bm25: Elastic-Quality Full Text Search Inside Postgres
The issue for geo search is here: https://github.com/quickwit-oss/tantivy/issues/44
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Grimoire - A recipe management application.
Search index : Custom-built using tantivy.
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A Compressed Indexable Bitset
The roaring bitmap variant is used only for the optional index (1 docid => 0 or 1 value) in the columnar storage (DocValues), not for the inverted index. Since this is used for aggregation, some queries may be a full scan.
The inverted index in tantivy uses bitpacked values of 128 elements with a skip index on top.
> I didn't follow the rest of your comment, select is what EF is good at, every other data structure needs a lot more scanning once you land on the right chunk. With BMI2 you can also use the PDEP instruction to accelerate the final select on a 64-bit block
The select for the sparse codec is a [simple array index access](https://github.com/quickwit-oss/tantivy/blob/main/columnar/s...), that is hard to beat. Compression is not good near the 5k threshold though.
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Job: Rust + Retrieval Systems at Etsy
Hi /r/rust, I’m a SWE on Etsy’s Retrieval Systems team where we’re building a platform based on rust and tantivy (https://github.com/quickwit-oss/tantivy). We’re looking to bring two new engineers onto the team.
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Announcing Velo - Your Rust-Powered Brainstorming and Note-Taking Tool
Quick Search: Easily find specific notes with Velo's fuzzy-search feature, powered by tantivy. tantivy might have been a little overkill, but it was really easy to integrate.
Folly
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Ask HN: How bad is the xz hack?
https://github.com/facebook/folly/commit/b1391e1c57be71c1e2a...
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Backdoor in upstream xz/liblzma leading to SSH server compromise
https://github.com/facebook/folly/pull/2153
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A lock-free ring-buffer with contiguous reservations (2019)
To set a HP on Linux, Folly just does a relaxed load of the src pointer, release store of the HP, compiler-only barrier, and acquire load. (This prevents the compiler from reordering the 2nd load before the store, right? But to my understanding does not prevent a hypothetical CPU reordering of the 2nd load before the store, which seems potentially problematic!)
Then on the GC/reclaim side of things, after protected object pointers are stored, it does a more expensive barrier[0] before acquire-loading the HPs.
I'll admit, I am not confident I understand why this works. I mean, even on x86, loads can be reordered before earlier program-order stores. So it seems like the 2nd check on the protection side could be ineffective. (The non-Linux portable version just uses an atomic_thread_fence SeqCst on both sides, which seems more obviously correct.) And if they don't need the 2nd load on Linux, I'm unclear on why they do it.
[0]: https://github.com/facebook/folly/blob/main/folly/synchroniz...
(This uses either mprotect to force a TLB flush in process-relevant CPUs, or the newer Linux membarrier syscall if available.)
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Appending to an std:string character-by-character: how does the capacity grow?
folly provides functions to resize std::string & std::vector without initialization [0].
[0] https://github.com/facebook/folly/blob/3c8829785e3ce86cb821c...
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Can anyone explain feedback of a HFT firm regarding implementation of SPSC lock-free ring-buffer queue?
My implementation was quite similar to Boost's spsc_queue and Facebook's folly/ProducerConsumerQueue.h.
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A Compressed Indexable Bitset
> How is that relevant?
Roaring bitmaps and similar data structures get their speed from decoding together consecutive groups of elements, so if you do sequential decoding or decode a large fraction of the list you get excellent performance.
EF instead excels at random skipping, so if you visit a small fraction of the list you generally get better performance. This is why it works so well for inverted indexes, as generally the queries are very selective (otherwise why do you need an index?) and if you have good intersection algorithms you can skip a large fraction of documents.
I didn't follow the rest of your comment, select is what EF is good at, every other data structure needs a lot more scanning once you land on the right chunk. With BMI2 you can also use the PDEP instruction to accelerate the final select on a 64-bit block: https://github.com/facebook/folly/blob/main/folly/experiment...
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Defer for Shell
C++ with folly's SCOPE_EXIT {} construct:
https://github.com/facebook/folly/blob/main/folly/ScopeGuard...
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Is there any facebook/folly community for discussion and Q&A?
Seems like github issues taking a long time to get any response: https://github.com/facebook/folly
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How a Single Line of Code Made a 24-Core Server Slower Than a Laptop
Can't speak for abseil and tbb, but in folly there are a few solutions for the common problem of sharing state between a writer that updates it very infrequently and concurrent readers that read it very frequently (typical use case is configs).
The most performant solutions are RCU (https://github.com/facebook/folly/blob/main/folly/synchroniz...) and hazard pointers (https://github.com/facebook/folly/blob/main/folly/synchroniz...), but they're not quite as easy to use as a shared_ptr [1].
Then there is simil-shared_ptr implemented with thread-local counters (https://github.com/facebook/folly/blob/main/folly/experiment...).
If you absolutely need a std::shared_ptr (which can be the case if you're working with pre-existing interfaces) there is CoreCachedSharedPtr (https://github.com/facebook/folly/blob/main/folly/concurrenc...), which uses an aliasing trick to transparently maintain per-core reference counts, and scales linearly, but it works only when acquiring the shared_ptr, any subsequent copies of that would still cause contention if passed around in threads.
[1] Google has a proposal to make a smart pointer based on RCU/hazptr, but I'm not a fan of it because generally RCU/hazptr guards need to be released in the same thread that acquired them, and hiding them in a freely movable object looks like a recipe for disaster to me, especially if paired with coroutines https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p05...
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Ask HN: What are some of the most elegant codebases in your favorite language?
Not sure if it's still the case but about 6 years ago Facebook's folly C++ library was something I'd point to for my junior engineers to get a sense of "good" C++ https://github.com/facebook/folly
What are some alternatives?
sonic - 🦔 Fast, lightweight & schema-less search backend. An alternative to Elasticsearch that runs on a few MBs of RAM.
abseil-cpp - Abseil Common Libraries (C++)
surrealdb - A scalable, distributed, collaborative, document-graph database, for the realtime web
Boost - Super-project for modularized Boost
milli - Search engine library for Meilisearch ⚡️
Seastar - High performance server-side application framework
MeiliSearch - A lightning-fast search API that fits effortlessly into your apps, websites, and workflow
parallel-hashmap - A family of header-only, very fast and memory-friendly hashmap and btree containers.
quickwit - Cloud-native search engine for observability. An open-source alternative to Datadog, Elasticsearch, Loki, and Tempo.
EASTL - Obsolete repo, please go to: https://github.com/electronicarts/EASTL
fselect - Find files with SQL-like queries
OpenFrameworks - openFrameworks is a community-developed cross platform toolkit for creative coding in C++.