Hi Everyone,
+1
I’m aligned with moving the crate to the Datafusion community as the context about Datafusion internals doesn’t feel appropriate for an Iceberg specific package.
I do want to call out two against scenarios I thought of and make sure they are noted for the dev list.
1. If anyone wants to fork and Introduce a new feature in Iceberg-Rust and run Datafusion they will now have to fork and make changes in two places. Both Datafusion and Iceberg-Rust.
2. There is precedent in the Rust Apache GitHub packages of having a single repo hold two projects with Arrow-rs and Parquet.
I don’t think either is strong enough to argue against the maintenance and domain knowledge arguments made above and by others. If you disagree am I’m curious to understand why.
Best Regards, Kurtis To add more background about the relationship between comet and datafusion for those who are not familiar with them.
Apache datafusion is a popular extensible compute engine written in rust. Apache comet is an apache spark accelerator builton on apache datafusion, and also a subproject of apache datafusion.
datafusion-iceberg is an apache datafusion extension built on iceberg-rust, and comet's iceberg support is built on it. +1 for moving to DataFusion PMC. The iceberg-datafusion integration is
very important for Comet.
On Mon, Aug 31, 2026 at 11:42 PM Xuanwo <[email protected]> wrote:
>
> TBH, I also support moving to the DataFusion PMC.
>
> - DataFusion is the largest dependency in iceberg-datafusion.
> - The largest downstream user of iceberg-datafusion is Comet, which shares many of the same PMC members as DataFusion.
>
> It feels natural to be part of the DataFusion PMC. As long as DF PMC is willing to accept this project, it LGTM.
>
> On Tue, Sep 1, 2026, at 12:03, Renjie Liu wrote:
>
> I don't think the testing should be a blocker of moving iceberg-datafusion out of iceberg-rust repo. From what I learn, most of the sqllogictests are in pr of modifying iceberg-datafusion integration, there are only few cases where we rely on sqllogictests to verify features.
>
> > How would that sound for the `iceberg-rust` community to grant a couple of Apache DataFusion PMCs committer access to the repository, limited to the `iceberg-datafusion` crate via a CODEOWNERS file, so that they can help push reviews and PRs forward independently?
>
> I'm not sure if this is feasible, but moving the iceberg-datafusion crate to apache datafusion project sounds a more reasonable approach to me. It's still governed by Apache, and most of the code is related to DataFusion, so I think the DataFusion community is in a better position to define the vision and design for it.
>
> On Mon, Aug 31, 2026 at 10:45 PM Gabriel Musat <[email protected]> wrote:
>
> Hi everyone,
>
> Based on these two facts:
> - There's a current reviewer bandwidth problem that hurts development velocity of the `iceberg-datafusion` crate currently hosted under `apache/iceberg-rust`.
> - There is value in maintaining the `iceberg-datafusion` crate inside `apache/iceberg-rust` for testing, design and governance.
>
> How would that sound for the `iceberg-rust` community to grant a couple of Apache DataFusion PMCs committer access to the repository, limited to the `iceberg-datafusion` crate via a CODEOWNERS file, so that they can help push reviews and PRs forward independently?
>
> Based on review history, I'd propose Matt Butrovich and Tim Saucer as two good candidates, but this would be completely up to the `iceberg-rust` community.
>
> On 2026/08/26 17:56:19 Shawn Chang wrote:
> > Hi all,
> >
> > Summarizing the discussion so far, including a few points raised in today’s
> > community sync.
> >
> > There seems to be general agreement that the current DataFusion integration
> > has a velocity/reviewer bandwidth problem, and moving it to a separate
> > repository could help DataFusion contributors iterate more independently.
> > At the same time, several open questions remain:
> >
> > -
> >
> > Whether repo separation is the right solution, versus expanding
> > DataFusion reviewer/committer participation in iceberg-rust.
> > -
> >
> > Where the boundary should be between engine specific integration and
> > Iceberg core functionality, and how to avoid duplicated or forked Iceberg
> > implementations. (how to avoid the case where Iceberg-datafusion moving
> > much faster than the core and eventually need a forked core API
> > implementation)
> > -
> >
> > How compatibility and end-to-end correctness testing should work across
> > repositories, since iceberg-rust still relies on DataFusion for integration
> > testing.
> > -
> >
> > Where the integration should live and how to keep it under Apache
> > governance while making it easy for both Iceberg and DataFusion
> > contributors to maintain.
> >
> > So I think the main question is not only whether to move the code, but how
> > to improve development velocity without losing the close design, testing,
> > and governance relationship between the engine integration and iceberg-rust
> > core.
> >
> >
> > Best,
> >
> > Shawn
> >
> > On Mon, Aug 24, 2026 at 4:14 AM Manu Zhang <[email protected]> wrote:
> >
> > > +1 moving the DataFusion integration and tests into a separate
> > > apache-governed repository. Can we bring this discussion to the Community
> > > Sync[1] this week?
> > >
> > > 1.
> > > https://docs.google.com/document/d/1YuGhUdukLP5gGiqCbk0A5_Wifqe2CZWgOd3TbhY3UQg/edit?tab=t.0
> > >
> > > On Mon, Aug 24, 2026 at 3:37 PM Renjie Liu <[email protected]>
> > > wrote:
> > >
> > >> Hi, Matt:
> > >>
> > >> Thanks for raising this.
> > >>
> > >> 1) Apache governance:
> > >>
> > >> I would +1 for putting this in an apache repo, for example a sub repo of
> > >> datafusion project. Shawn has stated most of the reasons, so I don't want
> > >> to repeat it again.
> > >>
> > >> 2) Where do tests live/how tests should be maintained?
> > >>
> > >> Initially I was thinking about putting sqllogictest in iceberg-rust, but
> > >> after second thought I'm leaning towards to put it in the new repo for two
> > >> reasons:
> > >> 1. It would be easier for developer of the datafusion-iceberg integration
> > >> to add tests
> > >> 2. It would make the dependency graph and version release easier. Though
> > >> the dependency is on crate level rather than repo level, the bi-direction
> > >> dependency may make version management weird and difficult.
> > >>
> > >> The downside of this approach is that it's a little unfriendly for
> > >> iceberg-rust developers, but I think it's less frequent for iceberg-rust
> > >> developers to add sqllogictests compared with datafusion-iceberg developers.
> > >>
> > >> 3) Dropping DataFusion dependencies from pyiceberg-core binding
> > >>
> > >> I'm not quite familiar with this part, but it sounds reasonable to me.
> > >>
> > >>
> > >> On Sat, Aug 22, 2026 at 6:50 AM Shawn Chang <[email protected]>
> > >> wrote:
> > >>
> > >>> Hi Matt,
> > >>>
> > >>> Thanks for raising this! I generally agree that we can move the
> > >>> datafusion
> > >>> integration to a separate repo if that helps more DataFusion experts to
> > >>> work on the integrations
> > >>>
> > >>> On the three considerations:
> > >>> 1) Apache governance:
> > >>> I think this is my biggest concern so far. This could not only affect
> > >>> contributors, but also whether the downstream users could continue to use
> > >>> the integration.
> > >>> Even if the code remains Apache-licensed, governance, release of
> > >>> artifacts,
> > >>> and contribution policies can matter for adoption.
> > >>> We should explore more about the option to keep it under an
> > >>> Apache-governed
> > >>> repository.
> > >>>
> > >>> 2) Where do tests live/how tests should be maintained?
> > >>>
> > >>> I think this is closely related to the governance question. To me, the
> > >>> broader question is: *how do we make it easy for people from both the
> > >>> Iceberg Rust and DataFusion communities to maintain the integration?*
> > >>>
> > >>> If we move it to a non-Apache repository, I worry that it could
> > >>> eventually
> > >>> look somewhat like the current Iceberg Java <> Trino integration: the
> > >>> integration primarily lives on the Trino side and is therefore mostly
> > >>> maintained by people who are already deeply involved in Trino.
> > >>>
> > >>> There is an important difference here, though. For Iceberg Java, Spark is
> > >>> arguably the primary engine integration and has a large Iceberg
> > >>> contributor
> > >>> base around it, so having the Trino integration maintained more
> > >>> independently is relatively natural. In Iceberg Rust today, DataFusion
> > >>> has
> > >>> a much more central role. It is by far the most mature engine integration
> > >>> in the project, is used by our SQLLogicTest infrastructure, and many
> > >>> users
> > >>> building on Iceberg Rust are also building on DataFusion. The overlap
> > >>> between the two communities is therefore much larger.
> > >>>
> > >>> Because of that, I would prefer that extracting the integration does not
> > >>> turn it into something that is effectively owned only by the DataFusion
> > >>> side. Ideally, both Iceberg Rust contributors and DataFusion contributors
> > >>> should be able to review changes, maintain compatibility, and evolve the
> > >>> integration together.
> > >>>
> > >>> 3) Dropping DataFusion dependencies from pyiceberg-core binding: I think
> > >>> it
> > >>> makes sense to make things simpler and have left a comment on the github
> > >>> issue with more detailed thoughts:
> > >>> https://github.com/apache/iceberg-rust/issues/3036
> > >>>
> > >>> Best,
> > >>> Shawn
> > >>>
> > >>> On Fri, Aug 21, 2026 at 11:23 AM Matt Butrovich <[email protected]>
> > >>> wrote:
> > >>>
> > >>> > Hello all,
> > >>> >
> > >>> >
> > >>> > I've never tried emailing two different project lists at once, but it
> > >>> was
> > >>> > suggested that I do so to try to track the conversation across both
> > >>> > communities. We'll see how this threads on the mailing lists.
> > >>> >
> > >>> >
> > >>> > There has been a GitHub Discussion
> > >>> >
> > >>> https://github.com/apache/iceberg-rust/discussions/2992#discussioncomment-18082533
> > >>> ,
> > >>> > a GitHub Issue https://github.com/apache/iceberg-rust/issues/3029, and
> > >>> > it's been a long topic of conversation in the past two weeks in both
> > >>> the
> > >>> > DataFusion and Iceberg Rust Community Calls to discuss moving the
> > >>> > DataFusion integration from Iceberg Rust to a separate repository. I
> > >>> will
> > >>> > try to summarize some of the major points as I understand them, but the
> > >>> > conversations are the ground truth and please feel free to correct me
> > >>> here.
> > >>> >
> > >>> >
> > >>> > The DataFusion TableProvider integration in Iceberg Rust makes
> > >>> DataFusion
> > >>> > a dependency for Iceberg Rust. The integration exists for multiple
> > >>> reasons:
> > >>> >
> > >>> > 1) an engine to execute Iceberg Rust's corpus of sqllogictest files
> > >>> >
> > >>> > 2) a TableProvider integration for DataFusion users to interact with
> > >>> > Iceberg tables
> > >>> >
> > >>> >
> > >>> > Some of the motivations to break out the integration:
> > >>> >
> > >>> > 1) There have been a number of issues and pull requests against the
> > >>> > DataFusion TableProvider in Iceberg Rust as users want to add more
> > >>> > features, and they often go stale. I don't believe there are many
> > >>> > committers/PMC members familiar with or using the DataFusion
> > >>> integration.
> > >>> >
> > >>> > 2) Iceberg Rust would like to stay as engine-agnostic as possible. A
> > >>> > recent DataFusion Ballista integration was declined for this reason
> > >>> > https://github.com/apache/iceberg-rust/pull/2613.
> > >>> >
> > >>> > 3) Other projects that rely on both Iceberg Rust and DataFusion (e.g.,
> > >>> > Comet) are blocked by Iceberg Rust upgrading its DataFusion and Arrow
> > >>> > dependencies before they can upgrade.
> > >>> >
> > >>> >
> > >>> > Some considerations for both communities:
> > >>> >
> > >>> > 1) Where would this DataFusion TableProvider live? Most specifically,
> > >>> > would it be an Apache-governed project? As folks like @andygrove point
> > >>> out,
> > >>> > this can affect whether some community members could contribute to it.
> > >>> > There is a datafusion-contrib org for DataFusion-related projects to
> > >>> have
> > >>> > visibility but no Apache governance, but there may be options to put it
> > >>> > under an Apache repository.
> > >>> >
> > >>> > 2) How would Iceberg Rust continue to run sqllogictests for regression
> > >>> > testing? Does this live in a different repository that depends on this
> > >>> new
> > >>> > Iceberg Rust TableProvider crate? Would we be able to test Pull
> > >>> Requests on
> > >>> > Iceberg Rust with sqllogictests?
> > >>> >
> > >>> > 3) @kevinqliu is familiar with the Python bindings in Iceberg Rust,
> > >>> and I
> > >>> > believe that DataFusion dependency might be removed as well, but that
> > >>> is
> > >>> > not the core focus of this conversation. He has also proposed removing
> > >>> that
> > >>> > and using the DataFusion Python bindings directly.
> > >>> >
> > >>> >
> > >>> > I'm sure I'm forgetting things, but this email is long enough.
> > >>> >
> > >>> >
> > >>> > Thanks everyone for the discussion thus far, and looking forward to
> > >>> more
> > >>> > input on this.
> > >>> >
> > >>> >
> > >>> > -Matt
> > >>> >
> > >>> >
> > >>> >
> > >>> >
> > >>>
> > >>
> >
>
> Xuanwo
>
> https://xuanwo.io/
>
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