Hi all,

I'm Yangyang, and I'm relatively new to the Fluss community. Hongshun and I
are planning to work on the union read support in the fluss-rust C++
bindings and bring it into StarRocks as a native connector
(StarRocks/starrocks#75785).


Thanks Anton for the great advice! As a newcomer, I'd really appreciate any
guidance or suggestions from the community.


Looking forward to contributing!


Best,

Yangyang

Anton Borisov <[email protected]> 于2026年7月3日周五 16:35写道:

> Hi Hongshun,
>
> Thanks, this sounds like a very useful landing case.
> Since StarRocks support relies on the same union-read / Paimon lake
> path covered by Theme 2, it fits the direction well. From the
> fluss-rust side, I think the important part is to define the common
> union-read semantics clearly, and then make sure the Rust client and
> C++ bindings expose the right primitives for integrations like
> StarRocks to build on.
>
> So this looks like a good validation of the Theme 2 direction, and
> also a useful reminder that the lake/log union read should not be
> DataFusion-specific.
>
> -- Anton
>
> пт, 3 июл. 2026 г. в 09:10, Hongshun Wang <[email protected]>:
> >
> > Hi Anton,
> > We will also support union read in StarRocks in Fluss C++ (
> > https://github.com/StarRocks/starrocks/issues/75785), and Yangyang(
> > https://github.com/naivedogger) and I will do it. This way, our Rust
> client
> > ecosystem can become more than just a demo.
> >
> > Best,
> > Hongshun
> >
> > On Fri, Jul 3, 2026 at 3:42 PM Anton Borisov <[email protected]>
> wrote:
> >
> > > Hi all,
> > >
> > > Thanks Forward, Hongshun and Junbo.
> > >
> > > On the release framing: I agree we should avoid making "0.3.0" the
> > > public target name once fluss-rust is consolidated into the main Fluss
> > > repo. It was a useful shorthand while fluss-rust had its own
> > > versioning, but after FIP-40 it is probably clearer to talk about the
> > > next post-consolidation Fluss release scope.
> > > My reading is that consensus is forming around the following shape, so
> > > let's define the roadmap like this for the time being:
> > >
> > > Theme 1  DataFusion integration adapter
> > > This looks like the main must-have item. There seems to be agreement
> > > that it should be a standalone adapter over the Rust core, not a
> > > bundled engine, and that Arrow/DataFusion versions should be pinned
> > > consistently across the workspace.
> > >
> > > Theme 2  Lake + log union read
> > > This also looks like a must-have scope. Paimon-first seems to be the
> > > pragmatic path, with the lake-side dependencies isolated in a separate
> > > crate. We should be careful with the boundary semantics for PK tables,
> > > especially how newer log records are applied over the lake snapshot.
> > >
> > > Theme 3  Predicate pushdown
> > > There also seems to be agreement that predicate pushdown is
> > > high-value, especially for both the DataFusion adapter and gateway
> > > read paths. I would still keep it as stretch unless based on the
> > > current capacity and amount of contributors. In the interim, we can
> > > push predicates into the lake side where supported and apply the
> > > remaining filters over the real-time log tail.
> > >
> > > Theme 4  Gateway
> > > For Gateway, I think the discussion is converging toward treating it
> > > as a separate  FIP from the core fluss-rust roadmap, especially if we
> > > split the plain REST API and SQL surface.
> > >
> > > The auth/authz questions Hongshun raised are important and probably
> > > belong in that Gateway design rather than being hidden inside the rust
> > > roadmap. My initial take is that gateway-side authentication can be
> > > independent, but authorization should stay aligned with Fluss
> > > server-side ACL semantics. Whether the gateway uses a single service
> > > identity or delegated user identities is a real design choice and
> > > affects connection management, so it deserves explicit discussion in
> > > the Gateway FIP.
> > >
> > > On the production-readiness gap Hongshun mentioned: I agree this is
> > > important, but I would separate it from the analytical surface itself.
> > > The goal is to close these gaps, while first bringing the core
> > > capabilities into place. I would treat this as a separate
> > > production-readiness track/umbrella issue as part of the
> > > post-consolidation work. Once fluss-rust is consolidated into the main
> > > repo, we should also test it regularly against the current Fluss
> > > build, so compatibility and stability issues are caught earlier.
> > >
> > > For today’s community meeting, I added the fluss-rust roadmap topic. I
> > > can summarize the dev@ discussion so far and keep it clearly framed as
> > > discussion status, not a final decision. Junbo, it would be good if
> > > you could also briefly cover the prototype /lake kernel /gateway parts
> > > you explored in code. It will be useful to understand the scope and
> > > the work we can integrate back.
> > >
> > > -- Anton
> > >
> > > пт, 3 июл. 2026 г. в 07:42, Junbo Wang <[email protected]>:
> > > >
> > > > Hi Hongshun,
> > > >
> > > > Good point — fluss-rust is currently at 0.1.0 with master tracking
> > > 0.2.0, so "0.3.0" was just our shorthand here. Once FIP-40 lands and
> > > fluss-rust moves into the fluss repo, it would naturally follow fluss
> > > versioning — likely the release after 1.0. I'll update the framing to
> > > reflect that.
> > > >
> > > >
> > > > Best regards,
> > > > Junbo Wang
> > > >
> > > > > 2026年7月3日 14:16,Hongshun Wang <[email protected]> 写道:
> > > > >
> > > > > Hi Junbo,
> > > > > What's 0.3.0? Since fluss-rust will be merged into fluss repo,
> maybe
> > > fluss
> > > > > release-1.0?
> > > > >
> > > > > Best,
> > > > > Hongshun
> > > > >
> > > > > On Fri, Jul 3, 2026 at 11:27 AM Junbo Wang <[email protected]>
> > > wrote:
> > > > >
> > > > >> Thanks Forward and Hongshun for the thoughtful input.
> > > > >>
> > > > >> On ForwardXu's question about the target release — I've been
> thinking
> > > a
> > > > >> bit about the 0.3.0 scope, and would like to share my personal
> take,
> > > mostly
> > > > >> as a starting point for discussion.
> > > > >>
> > > > >> A possible 0.3.0 scope
> > > > >>
> > > > >> FIP-40: consolidate fluss-rust into apache/fluss. thanks to Anton
> for
> > > > >> already opening the PR-3401 <
> > > https://github.com/apache/fluss/pull/3401>
> > > > >> DataFusion integration adapter (Theme 1), as a fluss-rust
> submodule.
> > > > >> Lake + log union read, Paimon-first (Theme 2), as a separate
> > > submodule so
> > > > >> lake-side dependencies stay isolated from the core. S
> > > > >> erver-side filter pushdown (Theme 3) — would be great to have if
> > > capacity
> > > > >> allows, but I'd suggest keeping it optional rather than a hard
> > > requirement
> > > > >> for 0.3.0.
> > > > >>
> > > > >> Gateway — perhaps outside 0.3.0
> > > > >>
> > > > >> Once fluss-rust is consolidated into apache/fluss, it might make
> > > sense for
> > > > >> the gateway to live as its own module depending on fluss-rust,
> rather
> > > than
> > > > >> being tied to the 0.3.0 release train. That would also give the
> > > auth/authz
> > > > >> questions Hongshun raised some room to be designed in a dedicated
> FIP.
> > > > >>
> > > > >> Just my personal thinking — happy to adjust based on what others
> feel
> > > is
> > > > >> right.
> > > > >>
> > > > >>
> > > > >> Best regards,
> > > > >> Junbo Wang
> > > > >>
> > > > >>> 2026年7月2日 11:47,Forward Xu <[email protected]> 写道:
> > > > >>>
> > > > >>> Hi Anton,
> > > > >>>
> > > > >>> Thanks for putting this together, and thanks to everyone who
> landed
> > > the
> > > > >>> previous roadmap. Framing the next phase around "fluss-rust as a
> > > > >>> first-class analytical query surface" makes a lot of sense to me
> — it
> > > > >>> builds naturally on the analytical primitives we just shipped. A
> few
> > > > >>> thoughts, roughly following your structure.
> > > > >>>
> > > > >>> *Theme 1 — DataFusion integration adapter [MUST-HAVE]* +1. I
> strongly
> > > > >> agree
> > > > >>> it should be an *adapter over the Rust core*, not a bundled
> engine.
> > > > >> Keeping
> > > > >>> fluss-datafusion as a standalone crate exposing TableProvider +
> > > > >>> CatalogProvider/SchemaProvider keeps the dependency direction
> clean
> > > and
> > > > >>> lets any DataFusion-based consumer (or the gateway) opt in.
> Mapping
> > > > >>> projection/filter/limit pushdown onto the existing access paths
> (PK
> > > > >>> equality → lookup, bucket-key prefix → prefix lookup, LIMIT →
> bounded
> > > > >> scan,
> > > > >>> else log scan) is the right approach. One thing worth nailing
> down
> > > early
> > > > >> is
> > > > >>> the exactness contract we report back to DataFusion (
> > > > >>> TableProviderFilterPushDown::Exact vs Inexact), since getting
> that
> > > wrong
> > > > >>> silently drops or double-applies filters.
> > > > >>>
> > > > >>> *Theme 2 — Lake + log union read (Paimon-first) [MUST-HAVE]* +1,
> and
> > > > >>> Paimon-first is the right call — reusing paimon-rust by wrapping
> an
> > > > >>> existing reader is low-risk, and the
> lake-snapshot-records-log-offset
> > > > >>> design gives us a clean stitch point. Starting bounded-batch and
> > > > >> deferring
> > > > >>> streaming also de-risks correctness of the log-offset boundary
> > > before we
> > > > >>> add continuous reads. The main correctness edge I'd like to see
> > > covered
> > > > >> is
> > > > >>> the boundary semantics for PK tables when applying newer log
> records
> > > over
> > > > >>> the lake snapshot (dedup/ordering at the tiered offset).
> > > > >>>
> > > > >>> *Theme 3 — Foundations / server-side filter pushdown [STRETCH]*
> Agree
> > > > >> this
> > > > >>> is a stretch, but it's the item with the highest leverage since
> it
> > > prunes
> > > > >>> both lake and log scans and unblocks the gateway's filter
> pushdown.
> > > > >>> Cross-checking against the Java PredicateConverter semantics is
> > > important
> > > > >>> so both clients behave identically. If capacity allows, I'd lean
> > > toward
> > > > >>> pulling at least the simple value-predicate cases forward, since
> > > Themes 1
> > > > >>> and 4 both benefit.
> > > > >>>
> > > > >>> *Theme 4 — Gateway [STRETCH]* The "REST is the no-regret floor,
> SQL
> > > is
> > > > >> the
> > > > >>> ceiling deferred until Themes 1–2" framing is a good way to think
> > > about
> > > > >> it.
> > > > >>> Keeping it a thin, stateless HTTP frontend over the existing
> client
> > > > >>> primitives (one endpoint per primitive) sounds right and keeps
> scope
> > > > >>> contained.
> > > > >>>
> > > > >>> *Open questions*
> > > > >>>
> > > > >>>  - *Themes 1–2 must-have, rest stretch — reasonable?* Yes,
> ordering
> > > > >> looks
> > > > >>>  right to me. Nothing obviously missing.
> > > > >>>  - *Paimon first, Iceberg later?* Agree, provided the union-read
> > > path is
> > > > >>>  written against a lake abstraction so Iceberg/Lance slot in the
> same
> > > > >> way
> > > > >>>  rather than requiring a rewrite.
> > > > >>>  - *Pin one arrow/DataFusion version across core,
> union-read/lake,
> > > and
> > > > >>>  DF?* Strong +1 — we should pin a single Arrow/DataFusion version
> > > > >>>  workspace-wide; version skew between these crates is a common
> and
> > > > >> painful
> > > > >>>  source of breakage.
> > > > >>>  - *Separate crates: lake kernel, DataFusion adapter, gateway?*
> +1 to
> > > > >>>  separate crates. It matches the "adapter, not bundled engine"
> > > > >> principle and
> > > > >>>  keeps the DataFusion dependency out of the core for consumers
> that
> > > > >> don't
> > > > >>>  need it.
> > > > >>>
> > > > >>> One meta-question: do we have a rough sense of the target release
> > > > >> (0.3.0?)
> > > > >>> these must-haves land in, so we can size the Theme 3/4 stretch
> work
> > > > >>> accordingly?
> > > > >>>
> > > > >>> Thanks again — happy to help on the DataFusion adapter side.
> > > > >>>
> > > > >>> Best,
> > > > >>>
> > > > >>> ForwardXu
> > > > >>>
> > > > >>> Junbo Wang <[email protected]> 于2026年7月1日周三 22:41写道:
> > > > >>>
> > > > >>>>> I'd also like us to focus on closing the gap with the Java
> client
> > > on
> > > > >>>> predicate pushdown.
> > > > >>>> Agreed — predicate pushdown is a great optimization, and the
> read
> > > path
> > > > >>>> will benefit significantly from it.
> > > > >>>>
> > > > >>>>
> > > > >>>>
> > > > >>>> One thing that was missing in upstream paimon-rust was an
> > > > >>>> object-store-safe existence check in the filesystem catalog. It
> > > checked
> > > > >>>> whether database/table directories “exist”, which works on local
> > > > >>>> filesystems but can fail on S3/OSS because those directories are
> > > just
> > > > >>>> prefixes, not real objects. I forked it to fix that, so lake
> reads
> > > can
> > > > >>>> reliably open Paimon tables from object storage.
> > > > >>>>
> > > > >>>> Thanks again, Anton, for putting this roadmap together! I think
> we
> > > could
> > > > >>>> share it at the July 3rd community meeting. I've also been
> working
> > > on
> > > > >> some
> > > > >>>> designs around lake kernel read and the Fluss Gateway REST API —
> > > happy
> > > > >> to
> > > > >>>> discuss those as well if time allows.
> > > > >>>>
> > > > >>>>
> > > > >>>> Best regards,
> > > > >>>> Junbo Wang
> > > > >>>>
> > > > >>>>> 2026年6月25日 07:23,Anton Borisov <[email protected]> 写道:
> > > > >>>>>
> > > > >>>>> Hi Yuxia and Junbo,
> > > > >>>>>
> > > > >>>>> Yuxia, on PK changelog reads across the bindings: I have
> already
> > > > >>>>> prepared record-mode CDC for Rust, Python and C++. It's small,
> and
> > > > >>>>> the PK union read in Theme 2 needs it anyway.
> > > > >>>>>
> > > > >>>>> Junbo, I looked through your prototype branch. It is clear
> that a
> > > lot
> > > > >>>>> of Themes 1, 2 and 4 already exist there as working code and it
> > > does
> > > > >>>>> seem to answer two of the open questions: the three-way crate
> split
> > > > >>>>> (lake kernel / adapter / gateway), and pinning a single
> > > > >> Arrow/DataFusion
> > > > >>>>> version at the workspace level. +1 to both.
> > > > >>>>>
> > > > >>>>> Two separate FIPs with detailed design for REST/SQL gateway
> parts -
> > > > >>>> makes sense.
> > > > >>>>>
> > > > >>>>> One thing I noticed and want to discuss:
> > > > >>>>> The "lake read" currently depends on a fork of paimon-rust,
> can you
> > > > >> share
> > > > >>>>> what was missing in paimon-rust?
> > > > >>>>>
> > > > >>>>> I'd also like us to focus on closing the gap with the Java
> client
> > > on
> > > > >>>>> predicate pushdown.
> > > > >>>>> In the interim we can push predicates into the lake (Paimon
> already
> > > > >>>>> supports it) and apply them as a filter pass over the
> real-time log
> > > > >>>>> tail.
> > > > >>>>>
> > > > >>>>> Good to hear you want to drive this forward, given the
> prototype,
> > > that
> > > > >>>>> makes sense to me. I am happy to review the design and
> following
> > > PRs.
> > > > >>>>>
> > > > >>>>> Looking forward to the write-up with your findings.
> > > > >>>>>
> > > > >>>>> -- Anton
> > > > >>>>>
> > > > >>>>> вт, 23 июн. 2026 г. в 15:10, Junbo Wang <[email protected]
> >:
> > > > >>>>>>
> > > > >>>>>> Thanks Anton for kicking this off — funnily enough, I'd been
> > > arriving
> > > > >>>> at very similar conclusions while prototyping on my side, so
> let me
> > > > >> share a
> > > > >>>> bit of what came out of those experiments.
> > > > >>>>>>
> > > > >>>>>>> THEME 1: DATAFUSION INTEGRATION ADAPTER [MUST-HAVE]
> > > > >>>>>>
> > > > >>>>>> Agree. Having the DataFusion integration live in fluss-rust
> would
> > > make
> > > > >>>> it reusable across more downstream projects. One thing we might
> > > want to
> > > > >>>> keep in mind: it would probably be worth aligning the
> DataFusion and
> > > > >> Arrow
> > > > >>>> versions with pg-datafusion so the whole stack stays on a
> consistent
> > > > >> set of
> > > > >>>> versions.
> > > > >>>>>>
> > > > >>>>>>> THEME 2: LAKE + LOG UNION READ (PAIMON-FIRST) [MUST-HAVE]
> > > > >>>>>>
> > > > >>>>>> Agree. I'd lean toward putting this in a separate fluss-lake
> > > module
> > > > >>>> that exposes a client capable of doing the union read over the
> lake
> > > and
> > > > >> the
> > > > >>>> Fluss log. That way the lake-side dependencies stay isolated in
> > > their
> > > > >> own
> > > > >>>> module and don't bleed into the core fluss-rust code. One thing
> that
> > > > >> might
> > > > >>>> be worth flagging here: the lake side already supports predicate
> > > > >> pushdown,
> > > > >>>> while Fluss doesn't yet — so we'd probably think about how the
> union
> > > > >> read
> > > > >>>> handles that asymmetry in the interim.
> > > > >>>>>>
> > > > >>>>>> THEME 4: GATEWAY [STRETCH] — A thin HTTP frontend over the
> client
> > > > >>>>>>
> > > > >>>>>> I wonder if we could expand on this one a bit. My suggestion
> > > would be
> > > > >>>> to split the SQL REST surface and the plain REST API into two
> > > separate
> > > > >>>> FIPs. A read/write REST API on its own — somewhat in the spirit
> of
> > > > >>>> kafka-rest, covering reads, writes, and metadata management —
> would
> > > > >> already
> > > > >>>> be a quick win for broadening Fluss's data ingestion/access
> reach,
> > > and
> > > > >> it
> > > > >>>> doesn't depend on anything else. The SQL REST surface, on the
> other
> > > > >> hand,
> > > > >>>> has to wait on Themes 1–2, so it might make sense to split them
> and
> > > ship
> > > > >>>> the plain REST API first.
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>> Also, it might make sense to have the gateway as a separate
> crate
> > > > >>>> inside the Fluss project itself — especially since fluss-rust
> will
> > > be
> > > > >>>> moving into the Fluss repo anyway.
> > > > >>>>>>
> > > > >>>>>> On a personal note, this is something I'm really excited
> about and
> > > > >>>> would love to help push forward. I'll share a write-up of what
> came
> > > out
> > > > >> of
> > > > >>>> my demo experiments with the community over the next few weeks.
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>> Best regards,
> > > > >>>>>> Junbo Wang
> > > > >>>>>>
> > > > >>>>>>> 2026年6月23日 20:55,Yuxia Luo <[email protected]> 写道:
> > > > >>>>>>>
> > > > >>>>>>> Thanks for putting this together. +1 on the overall framing.
> My
> > > > >>>> answers to the open questions, plus one addition:
> > > > >>>>>>>
> > > > >>>>>>> Open questions:
> > > > >>>>>>> - Themes 1-2 as must-have, rest stretch: agree, the ordering
> > > makes
> > > > >>>> sense to me.
> > > > >>>>>>> - Paimon first, Iceberg later: +1. Reusing paimon-rust is the
> > > > >>>> pragmatic path, and the union-read design generalizes to
> Iceberg the
> > > > >> same
> > > > >>>> way later.
> > > > >>>>>>> - Pin one arrow/DataFusion version across core,
> union-read/lake,
> > > and
> > > > >>>> DF: yes, we should pin a single version. Letting these drift
> will
> > > cause
> > > > >>>> painful Arrow type/ABI mismatches across the crate boundary, so
> a
> > > shared
> > > > >>>> pinned version (bumped deliberately, not per-crate) is worth the
> > > > >> discipline.
> > > > >>>>>>> - Separate crates (lake kernel, DataFusion adapter,
> gateway): +1
> > > on
> > > > >>>> separate crates. It keeps the dependency surface clean - the
> > > adapter and
> > > > >>>> gateway are optional consumers, and the lake kernel shouldn't
> drag
> > > > >>>> DataFusion into anyone who only needs the core read path.
> > > > >>>>>>>
> > > > >>>>>>> One addition I'd like to propose for the scope:
> > > > >>>>>>> PK-table CHANGELOG read, and expose it across the bindings -
> > > > >>>> specifically C++ and Python - so non-Rust CDC consumers can
> > > subscribe.
> > > > >>>>>>>
> > > > >>>>>>> On 2026/06/22 14:49:52 Anton Borisov wrote:
> > > > >>>>>>>> Hi all,
> > > > >>>>>>>>
> > > > >>>>>>>> With the previous roadmap wrapping up - complex types
> > > > >>>>>>>> (Array/Row/Map/nesting), limit and prefix scan,
> schema-aware KV
> > > > >>>>>>>> decoding, the metrics framework, and write optimisations,
> > > thanks to
> > > > >>>>>>>> everyone who contributed and reviewed, I'd like to open
> > > discussion
> > > > >> on
> > > > >>>>>>>> the roadmap.
> > > > >>>>>>>>
> > > > >>>>>>>> I propose framing around a single goal: make fluss-rust a
> > > > >> first-class
> > > > >>>>>>>> analytical query surface - a Rust-native SQL/DataFrame path
> over
> > > > >> Fluss
> > > > >>>>>>>> (DataFusion, and through it Polars/DuckDB/gateways),
> reading the
> > > > >> lake
> > > > >>>>>>>> tier at scale, built on the analytical primitives we just
> > > landed.
> > > > >>>>>>>>
> > > > >>>>>>>> As before, I grouped the items into themes with an initial
> > > > >> must-have /
> > > > >>>>>>>> stretch positioning. Please push back where you disagree.
> > > > >>>>>>>>
> > > > >>>>>>>> THEME 1: DATAFUSION INTEGRATION ADAPTER [MUST-HAVE]
> > > > >>>>>>>> A standalone fluss-datafusion crate exposing TableProvider +
> > > Catalog
> > > > >>>>>>>> over the existing client, so SELECT ... FROM . works from
> any
> > > > >>>>>>>> DataFusion-based engine. It should be framed as an
> integration
> > > > >> adapter
> > > > >>>>>>>> over the Rust core, not a bundled engine. A gateway
> (FIP-32) or
> > > any
> > > > >>>>>>>> analytical consumer can use it or not.
> > > > >>>>>>>>
> > > > >>>>>>>> Scope: TableProvider + CatalogProvider/SchemaProvider
> backed by
> > > the
> > > > >>>>>>>> metadata path.
> > > > >>>>>>>>
> > > > >>>>>>>> Map DataFusion's projection/filter/limit pushdown onto the
> > > client's
> > > > >>>>>>>> existing access paths: a full primary-key equality becomes a
> > > > >> lookup, a
> > > > >>>>>>>> bucket-key prefix becomes a prefix lookup, LIMIT becomes a
> > > bounded
> > > > >>>>>>>> scan, otherwise a log scan. Filters an access path fully
> > > satisfies
> > > > >> are
> > > > >>>>>>>> reported exact, the rest are left for DataFusion to apply
> > > > >> (server-side
> > > > >>>>>>>> filter pushdown is Theme 3).
> > > > >>>>>>>>
> > > > >>>>>>>> THEME 2: LAKE + LOG UNION READ (PAIMON-FIRST) [MUST-HAVE]
> > > > >>>>>>>> A client-side read that presents a lake-enabled table as one
> > > table.
> > > > >>>>>>>> Its history is tiered to the lake (Paimon) and recent
> writes are
> > > > >> still
> > > > >>>>>>>> in the Fluss log, the lake snapshot records the log offset
> it
> > > > >> covers,
> > > > >>>>>>>> so we read the lake up to that offset and the Fluss log
> past it,
> > > > >> then
> > > > >>>>>>>> combine.
> > > > >>>>>>>> Scope:
> > > > >>>>>>>> - Per bucket: the lake snapshot plus the Fluss log past the
> > > tiered
> > > > >>>> offset.
> > > > >>>>>>>> - Log tables: concatenate the two. PK tables: apply the
> newer
> > > log
> > > > >>>>>>>> records to get current state.
> > > > >>>>>>>> - Paimon first, reusing paimon-rust, Iceberg/Lance later the
> > > same
> > > > >>>>>>>> way. The DataFusion adapter reads lake-enabled tables
> through
> > > this
> > > > >>>>>>>> path.
> > > > >>>>>>>> - Bounded batch first, streaming later
> > > > >>>>>>>>
> > > > >>>>>>>> Reusing paimon-rust means wrapping an existing reader, so
> it's
> > > > >> rather
> > > > >>>>>>>> feasible and straightforward.
> > > > >>>>>>>>
> > > > >>>>>>>> THEME 3: FOUNDATIONS [STRETCH]
> > > > >>>>>>>> Server-side value-predicate (filter) pushdown. The proto
> field
> > > > >> exists,
> > > > >>>>>>>> but the client currently sends none. This prunes lake/log
> scans
> > > and
> > > > >>>>>>>> unblocks the gateway's filter pushdown (the open question I
> > > raised
> > > > >> for
> > > > >>>>>>>> 0.2.0), cross-checked against the Java PredicateConverter
> > > semantics.
> > > > >>>>>>>>
> > > > >>>>>>>> THEME 4: GATEWAY [STRETCH]
> > > > >>>>>>>> A thin HTTP frontend over the client we already have
> > > independent of
> > > > >>>>>>>> Themes 1–3. It's how non-Rust/non-SQL clients (TS/JS,
> > > microservices,
> > > > >>>>>>>> curl) write to Fluss and do simple key access.
> > > > >>>>>>>> - Write: upsert/append, delete, create/drop tables,
> metadata.
> > > The
> > > > >>>>>>>> mature client write path essentially.
> > > > >>>>>>>> - Read: point lookup, prefix lookup, bounded log / CDC poll
> -
> > > one
> > > > >>>>>>>> endpoint per existing primitive, bounded and stateless.
> > > > >>>>>>>> The tradeoff: no joins, filters, or aggregations - that's
> the
> > > SQL
> > > > >>>>>>>> surface, and it needs the adapter and probably will be an
> > > ongoing
> > > > >>>>>>>> effort to optimise later.
> > > > >>>>>>>> - If Themes 1–2 ship, we unlock SQL frontends on top -
> > > PostgreSQL
> > > > >>>>>>>> via datafusion-postgres, as one example
> > > > >>>>>>>> In short: REST is the no-regret floor, SQL is the ceiling
> > > deferred
> > > > >>>>>>>> until Themes 1–2.
> > > > >>>>>>>>
> > > > >>>>>>>> PARALLEL TRACK: ELIXIR + BINDING EXPOSURE
> > > > >>>>>>>> Continue Elixir parity and expose newly-landed primitives
> > > (prefix
> > > > >>>>>>>> lookup, etc.) across Python / C++ / Elixir.
> > > > >>>>>>>>
> > > > >>>>>>>> GOVERNANCE TRACK
> > > > >>>>>>>> FIP-40: Consolidate apache/fluss-rust into apache/fluss -
> PR is
> > > > >> ready,
> > > > >>>>>>>> looks pretty good, waiting for a good moment to
> rebase/merge.
> > > > >>>>>>>>
> > > > >>>>>>>> OPEN QUESTIONS
> > > > >>>>>>>> - Themes 1–2 must-have, the rest stretch. Reasonable?
> Anything
> > > > >>>>>>>> missing or mis-ordered?
> > > > >>>>>>>> - Paimon first, Iceberg later?
> > > > >>>>>>>> - Pin one arrow/DataFusion version across core,
> > > union-read/lake, and
> > > > >>>> DF?
> > > > >>>>>>>> - Separate crates: lake kernel, DataFusion adapter, gateway?
> > > > >>>>>>>>
> > > > >>>>>>>> Looking forward to feedback.
> > > > >>>>>>>>
> > > > >>>>>>>> -- Anton
> > > > >>>>>>>>
> > > > >>>>>>
> > > > >>>>
> > > > >>>>
> > > > >>
> > > > >>
> > > >
> > >
>

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