dictomaton
pyroscope
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dictomaton | pyroscope | |
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2 | 56 | |
129 | 7,382 | |
- | - | |
1.8 | 9.6 | |
about 2 years ago | about 1 year ago | |
Java | Go | |
Apache License 2.0 | GNU Affero General Public License v3.0 |
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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.
dictomaton
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Calculate the difference and intersection of any two regexes
Say you want to compute all strings of length 5 that the automaton can generate. Conceptually the nicest way is to create an automaton that matches any five characters and then compute the intersection between that automaton and the regex automaton. Then you can generate all the strings in the intersection automaton. Of course, IRL, you wouldn't actually generate the intersection (you can easily do this on the fly), but you get the idea.
Automata are really a lost art in modern natural language processing. We used to do things like store a large vocabulary in an deterministic acyclic minimized automaton (nice and compact, so-called dictionary automaton). And then to find, say all words within Levenshtein distance 2 of hacker, create a Levenshtein automaton for hacker and then compute (on the fly) the intersection between the Levenshtein automaton and the dictionary automaton. The language of the automaton is then all words within the intersection automaton.
I wrote a Java package a decade ago that implements some of this stuff:
https://github.com/danieldk/dictomaton
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Ask HN: What are some 'cool' but obscure data structures you know about?
Also related: Levenshtein automata - automata for words that match every word within a given Levenshtein distance. The intersection of a Levenshtein automaton of a word and a DAWG gives you an automaton of all words within the given edit distance.
I haven't done any Java in years, but I made a Java package in 2013 that supports: DAWGs, Levenshtein automata and perfect hash automata:
https://github.com/danieldk/dictomaton
pyroscope
- Grafana Phlare, open source database for continuous profiling at scale
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The pros and cons of eBPF profiling in K8s
What do you mean? pyroscope.io was slow for you? or the blog?
- Go garbage collector doesn't release memory
- Pyroscope - Continuous profiling platform
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Ask HN: What are some 'cool' but obscure data structures you know about?
Tries (or prefix trees).
We use them a lot at Pyroscope for compressing strings that have common prefixes. They are also used in databases (e.g indexes in Mongo) or file formats (e.g debug symbols in macOS/iOS Mach-O format are compressed using tries).
We have an article with some animations that go into details about tries in case anyone's interested [0].
[0] https://github.com/pyroscope-io/pyroscope/blob/main/docs/sto...
- How to add dynamic tags/labels to Java profiles (example)
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Question: How do you handle oversized heap analysis?
You could use continuous profiling with Pyroscope which uses async-profiler under the hood, but with the added functionality that you can add relevant tags to your VMs (example).
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JFR (Java Flight Recorder) Parser written in Go
Java Flight Recorder (JFR) is a format for collecting diagnostic and profiling data from Java applications. A while back someone created an issue for Pyroscope , an open source continuous profiler written in Go, to support ingesting profiles in JFR format, but there were no existing parsers that were also written in Go.
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flamegraph.com - a new website for uploading, analyzing, and sharing pprof profiles
This cloud version is actually a slimmed-down version of Pyroscope which is open source and so you can run it locally.
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We created flamegraph.com - A website for uploading, analyzing, and sharing flamegraphs
At Pyroscope (open source continuous profiling) we use flamegraphs extensively to visualize and analyze profiling data. However, one of the worst parts about using flamegraphs for analysis is that they are kind of annoying to share.
What are some alternatives?
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multiversion-concurrency-contro
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minisketch - Minisketch: an optimized library for BCH-based set reconciliation
SheetJS js-xlsx - 📗 SheetJS Spreadsheet Data Toolkit -- New home https://git.sheetjs.com/SheetJS/sheetjs
TablaM - The practical relational programing language for data-oriented applications
Oat++ - 🌱Light and powerful C++ web framework for highly scalable and resource-efficient web application. It's zero-dependency and easy-portable.