Add Community Highlights 2025 blog post

_posts/2026-03-10-arrow-2025-highlights.md

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+---
+layout: post
+title: "Community Highlights 2025"
+date: "2026-03-11 00:00:00"
+author: pmc
+categories: [arrow]
+---
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+
+As you may have read in a previous blog post [^1], the Apache Arrow project
+recently turned 10 years old. We are grateful to everyone who helped us
+achieve this milestone, and we wanted to celebrate the community's
+accomplishments, by publishing our community highlights from 2025.
+
+We were inspired by the research by Dr Cat Hicks et al [^2], who found
+that concrete evidence of progress and accomplishments is instrumental
+to motivation and collaboration in developer teams. We think the same
+should hold for open source.
+
+---
+
+## New contributors
+
+It has been great to see many new contributors joining the project
+in the past year, with over 300 such individuals observed across the main
+Apache Arrow language implementations.
+
+| Repository/Implementation | Number of new contributors |
+|---|---|
+| arrow | 125 |
+| arrow-rs | 131 |
+| arrow-java | 28 |
+| arrow-go | 35 |
+<br>
+
+Worth highlighting is [alinaliBQ](https://github.com/alinaliBQ) who
+has been very active on the C++ Flight SQL ODBC Driver work together
+with [justing-bq](https://github.com/justing-bq) .
+
+[AntoinePrv](https://github.com/AntoinePrv) has done huge amount of
+work on the C++ Parquet implementation and [andishgar](https://github.com/andishgar)
+in the C++ Statistics area.
+
+[rmnskb](https://github.com/rmnskb) got involved with PyArrow in
+EuroPython sprints and has contributed multiple PRs since then. On the
+same event [paddyroddy](https://github.com/paddyroddy) also started with
+his first contribution and helped on the Python packaging side further on.
+
+
+[sdf-jkl](https://github.com/sdf-jkl), [liamzwbao](https://github.com/liamzwbao),
+[friendlymatthew](https://github.com/friendlymatthew), and
+[klion26](https://github.com/klion26) helped drive early Variant
+functionality in the Rust Parquet implementation and contributed a number
+of follow-up improvements.
+
+[jecsand838](https://github.com/jecsand838) drove major improvements to the
+Rust `arrow-avro` crate, work highlighted in the
+[Introducing Arrow Avro](https://arrow.apache.org/blog/2025/10/23/introducing-arrow-avro/)
+blog post.
+
+<!-- TODO: Add Go new contribs content -->
+
+#### Notable New Contributors in apache/arrow for 2025 are:
+
+| Author | # of prs | # of line changes (+ and -) |
+|---|---|---|
+| alinaliBQ | 36 | 15754 |
+| andishgar | 19 | 2926 |
+| AntoinePrv | 8 | 79257 |
+| rmnskb | 7 | 550 |
+| justing-bq | 4 | 12607 |
+
+#### Notable New Contributors in apache/arrow-rs for 2025 are:
+
+| Author | # of prs | # of line changes (+ and -) |
+|---|---|---|
+| scovich | 50 | 21006 |
+| jecsand838 | 38 | 26753 |
+| friendlymatthew | 33 | 7203 |
+| sdf-jkl | 4 | 388 |
+| rambleraptor | 4 | 333 |
+
+#### Notable New Contributors in apache/arrow-go for 2025 are:
+
+| Author | # of prs | # of line changes (+ and -) |
+|---|---|---|
+| Mandukhai-Alimaa | 6 | 1392 |
+| hamilton-earthscope | 5 | 2998 |
+
+
+## Release, Packaging and CI
+
+A lot of work has been done around the Continuous Integration and
+Developer Tools area. Ensuring a project with the reach of Arrow is properly working
+requires validation on a huge matrix of operating systems, architectures, libraries,
+versions. Needless to say that maintenance work has tremendous importance for the
+health of the project and the positive contributor experience.
+
+The most active contributors in the main repository are the ones contributing
+heavily on those areas while also providing the most review capacity. Shout out
+to [kou](https://github.com/kou) and [raulcd](https://github.com/raulcd) for
+taking such good care of the project and devoting countless hours so that everything
+runs smoothly.
+
+Notable contributions worth mentioning are enhanced release automation and
+reproducible builds for sources, migrating remaining AppVeyor and Azure jobs
+to GitHub actions, improving dev experience with more pre-commit checks instead
+of custom made linting tools.
+
+Moving some implementations out of the main repository (apache/arrow on GitHub)
+helped with easier releases and maintenance of the main repository and also of
+separate language implementations. The current apache/arrow repo now holds the format
+specification, C++ implementation together with all the bindings to it (Python, R, Ruby
+and C GLib). Other languages now live in their own apache/ repos namely
+[apache/arrow-java](https://github.com/apache/arrow-java),
+[apache/arrow-js](https://github.com/apache/arrow-js),
+[apache/arrow-rs](https://github.com/apache/arrow-rs),
+[apache/arrow-go](https://github.com/apache/arrow-go),
+[apache/arrow-nanoarrow](https://github.com/apache/arrow-nanoarrow),
+[apache/arrow-dotnet](https://github.com/apache/arrow-dotnet) and
+[apache/arrow-swift](https://github.com/apache/arrow-swift).
+
+#### Notable Contributors in apache/arrow for 2025 are:
+
+| Author | # of prs | # of line changes (+ and -) |
+|---|---|---|
+| kou | 221 | 141015 |
+| AntoinePrv | 8 | 79257 |
+| raulcd | 110 | 46645 |
+| pitrou | 101 | 36585 |
+| jbonofre | 1 | 20061 |
+
+
+#### Notable Components in apache/arrow for 2025 are:
+
+| Component label | # of merged prs | # of line changes (+ and -) |
+|---|---|---|
+| Parquet | 100 | 103828 |
+| C++ | 387 | 82744 |
+| FlightRPC | 43 | 52659 |
+| CI | 237 | 42249 |
+| Ruby | 74 | 20676 |
+
+
+## Migration of infrastructure from Voltron Data
+
+As Voltron Data has wound down its operations in 2025, the Arrow project
+had to migrate benchmarking infrastructure and nightly report from
+Voltron-managed services to an Arrow-managed AWS account. This work has been
+driven by [rok](https://github.com/rok).
+
+## Closing of Stale issues
+
+[thisisnic](https://github.com/thisisnic) was working on closing of stale
+issues in the apache/arrow repository which helped surfacing important
+issues that were overlooked or forgotten.
+
+## Code contributions
+
+### C++ implementation
+
+Community support for maintenance and development of the Acero C++
+is continuing with multiple bigger contributions in 2025 done by
+[pitrou](https://github.com/pitrou) and [zanmato1984](https://github.com/zanmato1984).
+
+Many kernels have been moved from the integrated compute module into
+a separate, optional package for improvement of modularity and distribution
+size when optional compute functionality is not being used. The work has
+been done by [raulcd](https://github.com/raulcd).
+
+### Arrow C++ Parquet implementation
+
+There have been multiple contributions to fix and improve fuzzing
+support for Parquet. Fuzzing work is led by [pitrou](https://github.com/pitrou)
+who is also one of the most active members of the community guiding other
+developers and supporting us with abundant review capacity.
+
+Multiple newer types have also been supported in the last year,
+namely: VARIANT, UUID, GEOMETRY and GEOGRAPHY contributed
+by [neilechao](https://github.com/neilechao) and
+[paleolimbot](https://github.com/paleolimbot).
+
+An important feature added has also been Content-Defined Chunking
+which improves deduplication of Parquet files with mostly identical
+contents, by choosing data page boundaries based on actual contents
+rather than a number of values [^3]. This work has been done by
+[kszucs](https://github.com/kszucs).
+
+There have been improvements in the Parquet encryption support for
+most of the releases in the last year. These efforts have been
+driven mostly by [EnricoMi](https://github.com/EnricoMi),
+[pitrou](https://github.com/pitrou), [adamreeve](https://github.com/adamreeve)
+and [kapoisu](https://github.com/kapoisu).
+
+### PyArrow
+
+A lot of work has been put into adding type annotations. It all
+started in July at EuroPython sprints and the code is now ready to be 
+reviewed and merged. Some more review capacity will be needed to get
+this over the finish line. The work has been championed by
+[rok](https://github.com/rok).
+
+### Rust
+
+Arrow Rust community invested heavily in the Rust parquet reader for
+which they created several blog posts [^4], [^5]. The work has been
+championed by [alamb](https://github.com/alamb) and
+[etseidl](https://github.com/etseidl).
+
+#### Notable Components in apache/arrow-rs for 2025 are:
+
+| component | merged_prs | line_changes |
+|---|---|---|
+| parquet | 333 | 140958 |
+| arrow | 436 | 76590 |
+| parquet-variant | 125 | 41832 |
+| api-change | 59 | 33938 |
+| arrow-avro | 48 | 29487 |
+
+### Java
+
+The biggest changes in apache/arrow-java for 2025 have been connected
+to Flight and Avro components plus Sphinx support due to the Java
+implementation being moved into a separate Apache repository.
+Contributors involved in the above are [lidavidm](https://github.com/lidavidm)
+and [martin-traverse](https://github.com/martin-traverse).
+
+### Go
+
+There has been a lot of work related to new variant type in the
+Parquet implementation done in apache/arrow-go all by
+[zeroshade](https://github.com/zeroshade).
+
+Noticeable emphasis was also visible on performance-focused PRs leading to
+the addition of row seeking, bloom filter reading/writing, and reduction of
+allocations in the Parquet library along with significant optimization work
+in the ``compute.Take` kernels. Shout out to [pixelherodev](https://github.com/pixelherodev)
+and [hamilton-earthscope](https://github.com/hamilton-earthscope) for the
+emphasis they placed on improving performance.
+
+### Nanoarrow
+
+Bigger work in nanoarrow include Decimal32/64 and ListView/LargeListView support,
+LZ4 and ZSTD decompression in the IPC reader, and broader packaging via Conan, Homebrew,
+and vcpkg. Contributors driving most above are [paleolimbot](https://github.com/paleolimbot)
+and [WillAyd](https://github.com/WillAyd).
+
+---
+
+## Arrow Summit 25
+
+One last thing to highlight would be our first Arrow Summit 25 that
+was held in Paris in October 2025. The event was a great success and
+it brought users, contributors and maintainers together. It
+definitely was a highlight of the year for many of us. Thanks to
+[raulcd](https://github.com/raulcd) and [pitrou](https://github.com/pitrou)
+for organizing the event.
+
+<!-- TODO: Would it be possible to add a group picture here? -->
+
+---
+
+## Thank you!
+
+We would like to thank every single contributor to Apache Arrow for
+being a part of this great community and project! Hope this blog
+post helps to validate all the work you have done and motivates us
+to continue collaborating and growing together!
+
+---
+
+<br>
+
+The Notebooks with the analysis for this blog post can be found
+in [^6].
+
+Note not all language implementations are mentioned. Some due to being
+moved into a separate repository in 2025 resulting in missing information
+for large amount of merged pull requests. Others due to having lower
+number of bigger contributions in the past year.
+
+
+---
+
+[^1]: [Apache Arrow is 10 years old 🎉](https://arrow.apache.org/blog/2026/02/12/arrow-anniversary/)
+[^2]: [Developer Thriving: Four Sociocognitive Factors That Create Resilient Productivity on Software Teams](https://ieeexplore.ieee.org/abstract/document/10491133)
+[^3]: [Parquet Content-Defined Chunking](https://huggingface.co/blog/parquet-cdc)
+[^4]: [A Practical Dive Into Late Materialization in arrow-rs Parquet Reads](https://arrow.apache.org/blog/2025/12/11/parquet-late-materialization-deep-dive/)
+[^5]: [3x-9x Faster Apache Parquet Footer Metadata Using a Custom Thrift Parser in Rust](https://arrow.apache.org/blog/2025/10/23/rust-parquet-metadata/)
+[^6]: [arrow-maintenance/explorations](https://github.com/arrow-maintenance/explorations/tree/main/yearly_highlights)
+