alamb commented on code in PR #756:
URL: https://github.com/apache/arrow-site/pull/756#discussion_r2787984811
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
Review Comment:
I would personally suggest removing this section -- it is already mentioned
above and I think it distracts from the main narrative about Arrow's stability
and widespread adoption.
> Union types cannot have a top-level validity bitmap anymore.
I suggest adding a link to the mailing list discussion in that text
https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27 and then
removing this section
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
Review Comment:
I personally suggest moving this paragraph up to the top (right after the
introduction)
I realize that the current blog structure is chronological, but I think
ordering it in descending order of importance would improve the flow -- if we
moved this paragraph to the start, the blog would start with a victory lap
about the stability and wide reaching impact (Arrow 1.0) and then discuss some
of the path to get there.
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
+
+We have been extremely cautious with version numbering and waited
+[until July 2020](https://arrow.apache.org/blog/2020/07/24/1.0.0-release/)
+before finally switching away from 0.x version numbers. This was signalling
+to the world that Arrow had reached its "adult phase" of making formal
compatibility
+promises, and that the Arrow formats were ready for wide consumption amongst
+the data ecosystem.
+
+## Apache Arrow, today
+
+Describing the breadth of the Arrow ecosystem today would take a full-fledged
+article of its own, or perhaps even multiple Wikipedia pages.
+
+As for the Arrow project, we will merely refer you to our official
documentation:
+
+1. [The various
specifications](https://arrow.apache.org/docs/format/index.html#)
+ that cater to multiple aspects of sharing Arrow data, such as
+ [in-process zero-copy
sharing](https://arrow.apache.org/docs/format/CDataInterface.html)
+ between producers and consumers that know nothing about each other, or
+ [executing database queries](https://arrow.apache.org/docs/format/ADBC.html)
+ that efficiently return their results in the Arrow format.
+
+2. [The implementation status page](https://arrow.apache.org/docs/status.html)
+ that lists the implementations developed officially under the Apache Arrow
+ umbrella; but keep in mind that multiple third-party implementations exist
+ in non-Apache projects, either open source or proprietary.
+
+However, that is only a small part of the landscape. The Arrow project hosts
+several official subprojects, such as [ADBC](https://arrow.apache.org/adbc)
+and [nanoarrow](https://arrow.apache.org/nanoarrow). A notable success story is
+[Apache DataFusion](https://datafusion.apache.org/), which began as an Arrow
+subproject and later graduated to become an independent top-level project in
the
+Apache Software Foundation, reflecting the maturity and impact of the
technology.
+
+Beyond these subprojects, many third-party efforts have adopted the Arrow
formats
+for efficient interoperability. [GeoArrow](https://geoarrow.org/) is an
impressive
+example of how building on top of existing Arrow formats and implementations
can
+enable groundbreaking efficiency improvements in a very non-trivial problem
space.
+
+It should also be noted that Arrow is often used hand in hand with
+[Apache Parquet](https://parquet.apache.org/), another open standard for
columnar
+data with a significant community overlap and a tremendous usage base.
+
+## Tomorrow
+
+We cannot really predict the future, and the project does not have a formal
roadmap.
+While the specifications are stable, they may still welcome additions to cater
for
+new use cases, as they have done in the past.
Review Comment:
Maybe we can make this a stronger statement, something like
```suggestion
The Apache Arrow community is first and foremost a consensus building
machine
and we will continue to welcome everyone who wishes to participate
constructively
to our community. We cannot really predict the future, and the project does
not have a formal roadmap.
While the specifications are stable, they may still evolve to cater new use
cases
based on community involvement, as they have done in the past.
```
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
+
+We have been extremely cautious with version numbering and waited
+[until July 2020](https://arrow.apache.org/blog/2020/07/24/1.0.0-release/)
+before finally switching away from 0.x version numbers. This was signalling
+to the world that Arrow had reached its "adult phase" of making formal
compatibility
+promises, and that the Arrow formats were ready for wide consumption amongst
+the data ecosystem.
+
+## Apache Arrow, today
+
+Describing the breadth of the Arrow ecosystem today would take a full-fledged
+article of its own, or perhaps even multiple Wikipedia pages.
+
+As for the Arrow project, we will merely refer you to our official
documentation:
+
+1. [The various
specifications](https://arrow.apache.org/docs/format/index.html#)
+ that cater to multiple aspects of sharing Arrow data, such as
+ [in-process zero-copy
sharing](https://arrow.apache.org/docs/format/CDataInterface.html)
+ between producers and consumers that know nothing about each other, or
+ [executing database queries](https://arrow.apache.org/docs/format/ADBC.html)
+ that efficiently return their results in the Arrow format.
+
+2. [The implementation status page](https://arrow.apache.org/docs/status.html)
Review Comment:
I think it would be valuable here to list some of the native libraries as a
way to more directly demonstrate the breadth of support.
For example, something like
```suggestion
2. Native software libraries for C, C++, C#, Go, Java, JavaScript, Julia,
MATLAB, Python, R, Ruby, and Rust. [The implementation status
page](https://arrow.apache.org/docs/status.html)
```
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
+
+We have been extremely cautious with version numbering and waited
+[until July 2020](https://arrow.apache.org/blog/2020/07/24/1.0.0-release/)
+before finally switching away from 0.x version numbers. This was signalling
+to the world that Arrow had reached its "adult phase" of making formal
compatibility
+promises, and that the Arrow formats were ready for wide consumption amongst
+the data ecosystem.
+
+## Apache Arrow, today
+
+Describing the breadth of the Arrow ecosystem today would take a full-fledged
+article of its own, or perhaps even multiple Wikipedia pages.
+
+As for the Arrow project, we will merely refer you to our official
documentation:
+
+1. [The various
specifications](https://arrow.apache.org/docs/format/index.html#)
+ that cater to multiple aspects of sharing Arrow data, such as
+ [in-process zero-copy
sharing](https://arrow.apache.org/docs/format/CDataInterface.html)
+ between producers and consumers that know nothing about each other, or
+ [executing database queries](https://arrow.apache.org/docs/format/ADBC.html)
+ that efficiently return their results in the Arrow format.
+
+2. [The implementation status page](https://arrow.apache.org/docs/status.html)
+ that lists the implementations developed officially under the Apache Arrow
+ umbrella; but keep in mind that multiple third-party implementations exist
+ in non-Apache projects, either open source or proprietary.
+
+However, that is only a small part of the landscape. The Arrow project hosts
+several official subprojects, such as [ADBC](https://arrow.apache.org/adbc)
+and [nanoarrow](https://arrow.apache.org/nanoarrow). A notable success story is
+[Apache DataFusion](https://datafusion.apache.org/), which began as an Arrow
+subproject and later graduated to become an independent top-level project in
the
+Apache Software Foundation, reflecting the maturity and impact of the
technology.
+
+Beyond these subprojects, many third-party efforts have adopted the Arrow
formats
+for efficient interoperability. [GeoArrow](https://geoarrow.org/) is an
impressive
+example of how building on top of existing Arrow formats and implementations
can
+enable groundbreaking efficiency improvements in a very non-trivial problem
space.
+
+It should also be noted that Arrow is often used hand in hand with
+[Apache Parquet](https://parquet.apache.org/), another open standard for
columnar
+data with a significant community overlap and a tremendous usage base.
+
+## Tomorrow
+
+We cannot really predict the future, and the project does not have a formal
roadmap.
+While the specifications are stable, they may still welcome additions to cater
for
+new use cases, as they have done in the past.
+
+The Arrow implementations are actively maintained, gaining new features, bug
fixes,
+performance improvements. We encourage people to contribute to their
implementation
+of choice, and to [engage with us and the
community](https://arrow.apache.org/community/).
+
+However, much of the progress is also happening in the broader ecosystem of
+third-party tools and libraries. Even for us, it has become almost impossible
+to keep track of all the things happening, on the same stable foundations that
+have been laid 10 years ago.
Review Comment:
Some wordsmithing for your consideration
```suggestion
Now and going forward, a large amount of Arrow related progress is happening
in the broader ecosystem of third-party tools and libraries. It is no longer
possible for us to keep track of all Arrow related
innovations and advances. We believe this is sign that the stable foundation
we laid 10 years ago
has become the cornerstone on which the next generation of products and
technologies will be
built.
```
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
+
+We have been extremely cautious with version numbering and waited
+[until July 2020](https://arrow.apache.org/blog/2020/07/24/1.0.0-release/)
+before finally switching away from 0.x version numbers. This was signalling
+to the world that Arrow had reached its "adult phase" of making formal
compatibility
+promises, and that the Arrow formats were ready for wide consumption amongst
+the data ecosystem.
+
+## Apache Arrow, today
+
+Describing the breadth of the Arrow ecosystem today would take a full-fledged
+article of its own, or perhaps even multiple Wikipedia pages.
+
+As for the Arrow project, we will merely refer you to our official
documentation:
+
+1. [The various
specifications](https://arrow.apache.org/docs/format/index.html#)
+ that cater to multiple aspects of sharing Arrow data, such as
+ [in-process zero-copy
sharing](https://arrow.apache.org/docs/format/CDataInterface.html)
+ between producers and consumers that know nothing about each other, or
+ [executing database queries](https://arrow.apache.org/docs/format/ADBC.html)
+ that efficiently return their results in the Arrow format.
+
+2. [The implementation status page](https://arrow.apache.org/docs/status.html)
+ that lists the implementations developed officially under the Apache Arrow
+ umbrella; but keep in mind that multiple third-party implementations exist
+ in non-Apache projects, either open source or proprietary.
+
+However, that is only a small part of the landscape. The Arrow project hosts
+several official subprojects, such as [ADBC](https://arrow.apache.org/adbc)
+and [nanoarrow](https://arrow.apache.org/nanoarrow). A notable success story is
+[Apache DataFusion](https://datafusion.apache.org/), which began as an Arrow
+subproject and later graduated to become an independent top-level project in
the
Review Comment:
A potentially relevant link is the blog announcement
```suggestion
[graduated to become an independent top-level
project](https://arrow.apache.org/blog/2024/05/07/datafusion-tlp)
##########
_posts/2026-02-10-arrow-anniversary.md:
##########
@@ -0,0 +1,168 @@
+---
+layout: post
+title: "Apache Arrow is 10 years old 🎉"
+date: "2026-02-09 00:00:00"
+author: pmc
+categories: [arrow]
+---
+<!--
+{% comment %}
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to you under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+{% endcomment %}
+-->
+
+The Apache Arrow project was officially established and had its
+[first git
commit](https://github.com/apache/arrow/commit/d5aa7c46692474376a3c31704cfc4783c86338f2)
+on February 5th 2016, and we are therefore enthusiastic to announce its 10-year
+anniversary!
+
+Looking back over these 10 years, the project has developed in many unforeseen
+ways and we believe to have delivered on our objective of providing agnostic,
+efficient, durable standards for the exchange of columnar data.
+
+## Apache Arrow 0.1.0
+
+The first Arrow release, numbered 0.1.0, was tagged on October 7th 2016. It
already
+featured the main data types that are still the bread-and-butter of most Arrow
datasets,
+as evidenced in this [Flatbuffers
declaration](https://github.com/apache/arrow/blob/e7080ef9f1bd91505996edd4e4b7643cc54f6b5f/format/Message.fbs#L96-L115):
+
+```flatbuffers
+
+/// ----------------------------------------------------------------------
+/// Top-level Type value, enabling extensible type-specific metadata. We can
+/// add new logical types to Type without breaking backwards compatibility
+
+union Type {
+ Null,
+ Int,
+ FloatingPoint,
+ Binary,
+ Utf8,
+ Bool,
+ Decimal,
+ Date,
+ Time,
+ Timestamp,
+ Interval,
+ List,
+ Struct_,
+ Union
+}
+```
+
+The [release
announcement](https://lists.apache.org/thread/6ow4r2kq1qw1rxp36nql8gokgoczozgw)
+made the bold claim that **"the metadata and physical data representation
should
+be fairly stable as we have spent time finalizing the details"**. Does that
promise
+hold? The short answer is: yes, almost! But let us analyse that in a bit more
detail:
+
+* the [Columnar format](https://arrow.apache.org/docs/format/Columnar.html),
for
+ the most part, has only seen additions of new datatypes since 2016.
+ **One single breaking change** occurred: Union types cannot have a
+ top-level validity bitmap anymore.
+
+* the [IPC
format](https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc)
+ has seen several minor evolutions of its framing and metadata format; these
+ evolutions are encoded in the `MetadataVersion` field which ensures that new
+ readers can read data produced by old writers. The single breaking change is
+ related to the same Union validity change mentioned above.
+
+## First cross-language integration tests
+
+Arrow 0.1.0 had two implementations: C++ and Java, with bindings of the former
+to Python. There were also no integration tests to speak of, that is, no
automated
+assessment that the two implementations were in sync (what could go wrong?).
+
+Integration tests had to wait for [November
2016](https://issues.apache.org/jira/browse/ARROW-372)
+to be designed, and the first [automated CI
run](https://github.com/apache/arrow/commit/45ed7e7a36fb2a69de468c41132b6b3bbd270c92)
+probably occurred in December of the same year. Its results cannot be fetched
anymore,
+so we can only assume the tests passed successfully. 🙂
+
+From that moment, integration tests have grown to follow additions to the
Arrow format,
+while ensuring that older data can still be read successfully. For example,
the
+integration tests that are routinely checked against multiple implementations
of
+Arrow have data files [generated in 2019 by Arrow
0.14.1](https://github.com/apache/arrow-testing/tree/master/data/arrow-ipc-stream/integration/0.14.1).
+
+## The lost Union validity bitmap
+
+As mentioned above, at some point the Union type lost its top-level validity
bitmap,
+breaking compatibility for the workloads that made use of this feature.
+
+This change was [proposed back in June
2020](https://lists.apache.org/thread/przo99rtpv4rp66g1h4gn0zyxdq56m27)
+and enacted shortly thereafter. It elicited no controversy and doesn't seem to
have
+caused any significant discontent among users, signaling that the feature was
+probably not widely used (if at all).
+
+Since then, there has been precisely zero breaking change in the Arrow
Columnar and IPC
+formats.
+
+## Apache Arrow 1.0.0
+
+We have been extremely cautious with version numbering and waited
+[until July 2020](https://arrow.apache.org/blog/2020/07/24/1.0.0-release/)
+before finally switching away from 0.x version numbers. This was signalling
+to the world that Arrow had reached its "adult phase" of making formal
compatibility
+promises, and that the Arrow formats were ready for wide consumption amongst
+the data ecosystem.
+
+## Apache Arrow, today
+
+Describing the breadth of the Arrow ecosystem today would take a full-fledged
Review Comment:
Maybe we can also include a link to the powered by page
https://arrow.apache.org/powered_by/ as a way to further illustrate its breadth
of adoption
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
