Thanks Matt,

I'll be on it this week.

Best
Prateek

On Mon, Jul 13, 2026 at 8:36 AM Matt Topol <[email protected]> wrote:

> There is also the Go implementation submitted by Arnav (
> https://github.com/apache/arrow-go/pull/704) which is waiting for updates.
>
> Just wanted to make sure it didn't get lost here.
>
> --Matt
>
> On Mon, Jul 13, 2026 at 11:30 AM PRATEEK GAUR <[email protected]> wrote:
>
> > Hi all,
> >
> > I'd like to share a status update on the ALP encoding effort and get a
> feel
> > from the community before starting a formal vote.
> >
> > We now have the specification plus implementations in both languages:
> >
> >     - Spec:         apache/parquet-format#557 — GH-533 Add ALP encoding
> > specification
> >     - C++ (Arrow):  apache/arrow#48345 — GH-48701 [C++][Parquet] Add
> ALPpd
> > encoding
> >     - Java:         apache/parquet-java#3397 — Parquet Java ALP
> > Implementation (by Vinoo)
> >
> > Current state:
> >
> >     - The C++ implementation has been through 3-4 rounds of review.
> >     - The Java implementation has been tracking well and has had initial
> >       reviews from contributors, with no major remaining issues.
> >     - Cross-language compatibility tests are passing: the Arrow C++
> decoder
> >       reads Java-written data bit-exactly across ~1.56M values and 18
> >       fixtures, covering V1 and V2 pages, multiple vector sizes, and
> > several
> >       real datasets — zero mismatches.
> >
> >  As raised in the java-pr we will be adding coverage for extreme values
> > (those requiring
> >  63-64 bits after FOR is applied) before we close a vote. We'll aim to
> get
> > that
> >  done in parallel.
> >
> > Plan: unless there are objections, I intend to start a vote at the end of
> > this week/early
> > next week.
> >
> > Thanks
> > Prateek
> >
> > On Wed, Jul 1, 2026 at 8:50 AM PRATEEK GAUR <[email protected]> wrote:
> >
> > > Hi Team,
> > >
> > > Just wanted to provide some updates on ALP.
> > > Micah and I have done 3-4 rounds of review for the c++ PR :
> > > https://github.com/apache/arrow/pull/48345
> > >
> > > For the Java implementation Vinoo has been working on following PR :
> > > https://github.com/apache/parquet-java/pull/3397
> > >
> > > Best
> > > Prateek
> > >
> > > On Tue, May 5, 2026 at 1:50 PM Micah Kornfield <[email protected]>
> > > wrote:
> > >
> > >> Hi Antoine,
> > >>
> > >> > Apologies if the question was already asked, but should we care
> about
> > >> > FLOAT16 for ALP? Can FLOAT + ALP be more efficient than FLOAT16 +
> > >> > BYTE_STREAM_SPLIT + LZ4 for example?
> > >>
> > >> It was.  We thought we could defer it for the following reasons:
> > >> 1.  It's not clear there are a lot of easy reference datasets to test
> > its
> > >> effectiveness.  It does look like there might be one or two on
> > huggingface
> > >> (e.g. https://huggingface.co/datasets/kikitora/curdie).
> > >> 2.  It seemed likely that float 16 was more likely used for values
> that
> > >> were less likely to reduce to decimal values.
> > >> 3.  It could be added as an extension later if needed.
> > >>
> > >> Cheers,
> > >> Micah
> > >>
> > >>
> > >> On Tue, May 5, 2026 at 1:40 PM Antoine Pitrou <[email protected]>
> > wrote:
> > >>
> > >> >
> > >> > Hello,
> > >> >
> > >> > Apologies if the question was already asked, but should we care
> about
> > >> > FLOAT16 for ALP? Can FLOAT + ALP be more efficient than FLOAT16 +
> > >> > BYTE_STREAM_SPLIT + LZ4 for example?
> > >> >
> > >> > Regards
> > >> >
> > >> > Antoine.
> > >> >
> > >> >
> > >> > Le 30/04/2026 à 01:10, PRATEEK GAUR a écrit :
> > >> > > Thanks Andrew and Micah for review feedback on the two PR's
> > >> > > 1) (c++ arrow repo)
> > >> https://github.com/apache/arrow/pull/48345/changes
> > >> > > 2) (parquet-format repo)
> > >> > https://github.com/apache/parquet-format/pull/557
> > >> > >
> > >> > > I have addressed all (unless I missed something) comments on the
> two
> > >> > PR's.
> > >> > >
> > >> > > Best
> > >> > > Prateek
> > >> > >
> > >> > > On Sat, Apr 25, 2026 at 1:08 PM PRATEEK GAUR <[email protected]>
> > >> wrote:
> > >> > >
> > >> > >> Thanks Andrew and Micah.
> > >> > >>
> > >> > >> `fair amount of feedback on at least the implementations`
> > >> > >> For the c++ I have already started addressing the feedback, I
> > should
> > >> be
> > >> > >> done with that Monday/Tuesday.
> > >> > >> I think Vinoo too has been making good progress on the Java
> > >> > implementation.
> > >> > >>
> > >> > >> Best
> > >> > >> Prateek
> > >> > >>
> > >> > >> On Sat, Apr 25, 2026 at 12:55 PM Andrew Lamb <
> > [email protected]
> > >> >
> > >> > >> wrote:
> > >> > >>
> > >> > >>> Got it. Thank you for the clarification -- I will try and look
> > into
> > >> the
> > >> > >>> spec and the Rust implementation[1] in this next week
> > >> > >>>
> > >> > >>> [1]: https://github.com/apache/arrow-rs/pull/9372
> > >> > >>>
> > >> > >>> On Sat, Apr 25, 2026 at 12:01 PM Micah Kornfield <
> > >> > [email protected]>
> > >> > >>> wrote:
> > >> > >>>
> > >> > >>>> Hi Andrew,
> > >> > >>>> I think there is a fair amount of feedback on at least the
> > >> > >>>> implementations, typically I think we've waited till they are
> > >> close to
> > >> > >>>> mergeable before a final vote.  Otherwise I agree we are very
> > >> close.
> > >> > >>>>
> > >> > >>>> -Micah
> > >> > >>>>
> > >> > >>>> On Saturday, April 25, 2026, Andrew Lamb <
> [email protected]
> > >
> > >> > wrote:
> > >> > >>>>
> > >> > >>>>> Thanks Prateek,
> > >> > >>>>>
> > >> > >>>>> I think from this content it looks to me like we are ready to
> > >> start a
> > >> > >>>>> vote to explicitly accept ALP into Parquet
> > >> > >>>>>
> > >> > >>>>> Does anyone know of a reason we should postpone it for longer?
> > >> > >>>>> Perhaps someone needs some more time to review?
> > >> > >>>>>
> > >> > >>>>> Andrew
> > >> > >>>>>
> > >> > >>>>>
> > >> > >>>>>
> > >> > >>>>> On Wed, Apr 22, 2026 at 1:00 PM PRATEEK GAUR <
> > [email protected]>
> > >> > >>>>> wrote:
> > >> > >>>>>
> > >> > >>>>>> Hi team,
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> Hope everyone is doing well. I got a chance to work through
> all
> > >> the
> > >> > >>>>>> remaining feedback and update the spec doc. Here are the new
> > >> > artifacts
> > >> > >>>>>>
> > >> > >>>>>> 1) Spec document :
> > >> > >>>>>>
> > >> >
> > >>
> >
> https://docs.google.com/document/d/1xz2cudDpN2Y1ImFcTXh15s-3fPtD_aWt/edit
> > >> > >>>>>>
> > >> > >>>>>> 2) Spec document in parquet format repo :
> > >> > >>>>>> https://github.com/apache/parquet-format/pull/557
> > >> > >>>>>>
> > >> > >>>>>> 3) Alp implementation in arrow c++ repo :
> > >> > >>>>>> https://github.com/apache/arrow/pull/48345/changes
> > >> > >>>>>>
> > >> > >>>>>> 4) Alp implementation in parquet-java repo : Work for Vinoo
> and
> > >> > Julien
> > >> > >>>>>>   https://github.com/apache/parquet-java/pull/3397
> > >> > >>>>>>
> > >> > >>>>>> 5) PR with test and benchmarking artifacts in parquet-testing
> > >> repo :
> > >> > >>>>>> https://github.com/apache/parquet-testing/pull/100
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> And
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>     - Go : Arnav just submitted an in progress implementation
> > in
> > >> Go.
> > >> > >>>>>>     https://github.com/apache/arrow-go/pull/704 (I haven't
> > >> started
> > >> > >>>>>>     looking at it yet)
> > >> > >>>>>>     - Rust : I remember Andrew mentioned that this work is
> also
> > >> in
> > >> > >>>>>>     progress (So 4 languages!)
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> *Arrow C++ implementation *
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> The PR is out and was also used by Antoine to report the
> > numbers
> > >> as
> > >> > >>>>>> reported here. Micah and Konstantin have given 1 round of
> > >> feedback
> > >> > >>>>>> and I'm addressing them today. Please note that the default
> > >> > >>>>>> optimization flag for compiling is O2 and not Q3. I got
> around
> > >> 70%
> > >> > >>>>>> performance improvement in the decoding speed when using the
> O3
> > >> > flag.
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> *Parqet-MR Java implementation (working with Vinoo and
> Julien)
> > >> and
> > >> > **Cross
> > >> > >>>>>> Language testing*
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>     Let me know if you have any questions or feedback.
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> Now pasting some performance numbers
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>    Table 1: C++ ALP Double Decode — Spotify Columns (Graviton
> > 3,
> > >> ARM
> > >> > >>>>>> Neoverse V1)
> > >> > >>>>>>
> > >> > >>>>>>
> ┌──────────────────┬──────────────┬──────────────┬─────────┐
> > >> > >>>>>>
> > >> > >>>>>>    │ Column           │  -O2 (MB/s)  │  -O3 (MB/s)  │
> Speedup │
> > >> > >>>>>>
> > >> > >>>>>>
> ├──────────────────┼──────────────┼──────────────┼─────────┤
> > >> > >>>>>>
> > >> > >>>>>>    │ valence          │     3,155    │     5,523    │
> 1.75x  │
> > >> > >>>>>>
> > >> > >>>>>>    │ danceability     │     3,233    │     5,685    │
> 1.76x  │
> > >> > >>>>>>
> > >> > >>>>>>    │ energy           │     3,197    │     5,652    │
> 1.77x  │
> > >> > >>>>>>
> > >> > >>>>>>    │ loudness         │     3,186    │     5,473    │
> 1.72x  │
> > >> > >>>>>>
> > >> > >>>>>>
> └──────────────────┴──────────────┴──────────────┴─────────┘
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>>
> > >> > >>>>>> On Wed, Feb 25, 2026 at 9:49 AM PRATEEK GAUR <
> > [email protected]
> > >> >
> > >> > >>>>>> wrote:
> > >> > >>>>>>
> > >> > >>>>>>> @Micah Kornfield <[email protected]> : Got it.
> > >> > >>>>>>>
> > >> > >>>>>>> @Andrew Lamb <[email protected]>
> > >> > >>>>>>>
> > >> > >>>>>>>
> > >> > >>>>>>>> Do you think it would be good to start moving the spec
> > >> development
> > >> > >>>>>>>> into
> > >> > >>>>>>>> markdown format, in preparation for finalizing it?
> > >> > >>>>>>>>
> > >> > >>>>>>>
> > >> > >>>>>>> Yes I'll update the numbers for some of the examples I have
> in
> > >> the
> > >> > >>>>>>> spec based
> > >> > >>>>>>> on the updated header size. Then we should be good to go for
> > the
> > >> > >>>>>>> markdown format.
> > >> > >>>>>>>
> > >> > >>>>>>> Thanks everyone!
> > >> > >>>>>>>
> > >> > >>>>>>>
> > >> > >>>>>>>>
> > >> > >>>>>>>> Andrew
> > >> > >>>>>>>>
> > >> > >>>>>>>> On Tue, Feb 17, 2026 at 7:28 PM PRATEEK GAUR <
> > >> [email protected]>
> > >> > >>>>>>>> wrote:
> > >> > >>>>>>>>
> > >> > >>>>>>>>> Hi team,
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> 1) Andrew
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>     - Thanks for working on test files. My PR did add all
> > the
> > >> > test
> > >> > >>>>>>>> files I
> > >> > >>>>>>>>>     used to benchmark on datasets. Maybe we can club it
> > >> together.
> > >> > >>>>>>>> WIll also
> > >> > >>>>>>>>> aid
> > >> > >>>>>>>>>     cross language testing
> > >> > >>>>>>>>>     -  Kosta Tarasov working on Rust implementation. This
> is
> > >> > great.
> > >> > >>>>>>>> Thanks
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> 2) Antoine
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>     - Thanks a lot for reporting the numbers on AMD. Looks
> > >> like
> > >> > you
> > >> > >>>>>>>> are
> > >> > >>>>>>>>>     getting 8X the decoding performance of BSS. This is
> > >> > amazing!!.
> > >> > >>>>>>>>>     - Thanks for acknowledging the sampling design.
> > >> > >>>>>>>>>     - I agree with you on Fastlanes. In some crude
> > >> experiments I
> > >> > >>>>>>>> didn't get
> > >> > >>>>>>>>>     a good perf benefit from it on Graviton3 (but maybe
> > there
> > >> was
> > >> > >>>>>>>> something
> > >> > >>>>>>>>>     wrong with my implementation).
> > >> > >>>>>>>>>     - Locking the 16bit exception encoding for the spec in
> > >> this
> > >> > >>>>>>>> case.
> > >> > >>>>>>>>>     - Awesome I think we have solved for all open
> questions
> > >> minus
> > >> > >>>>>>>> the
> > >> > >>>>>>>>>     version byte :). (will get back on this soon)
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> 3) Micah
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>     - FastLanes : The current spec does allow for using
> > >> FastLane
> > >> > >>>>>>>> with the
> > >> > >>>>>>>>>     configurable enum value for layout. We should be able
> to
> > >> > inject
> > >> > >>>>>>>> any
> > >> > >>>>>>>>> layout
> > >> > >>>>>>>>>     in the current design.
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> Working on resolving all remaining open comments on the
> spec
> > >> this
> > >> > >>>>>>>> week.
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> Best
> > >> > >>>>>>>>> Prateek
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>
> > >> > >>>>>>>>> On Tue, Feb 10, 2026 at 3:37 AM Steve Loughran <
> > >> > >>>>>>>> [email protected]>
> > >> > >>>>>>>>> wrote:
> > >> > >>>>>>>>>
> > >> > >>>>>>>>>> On Sun, 8 Feb 2026 at 18:12, Micah Kornfield <
> > >> > >>>>>>>> [email protected]>
> > >> > >>>>>>>>>> wrote:
> > >> > >>>>>>>>>>
> > >> > >>>>>>>>>>>
> > >> > >>>>>>>>>>>
> > >> > >>>>>>>>>>> It looks like the actual issue described for ORC in the
> > >> paper
> > >> > >>>>>>>> is that
> > >> > >>>>>>>>> it
> > >> > >>>>>>>>>>> has multiple sub-encodings in a batch.  This is
> different
> > >> then
> > >> > >>>>>>>> the
> > >> > >>>>>>>>> design
> > >> > >>>>>>>>>>> proposed here where there is still fixed encoding per
> page
> > >> in
> > >> > >>>>>>>> parquet.
> > >> > >>>>>>>>>>> Given reasonably sized pages I don't think branch
> > >> > >>>>>>>> misprediction should
> > >> > >>>>>>>>>> be a
> > >> > >>>>>>>>>>> big issue for new encodings.  I agree that we should be
> > >> > >>>>>>>> conservative in
> > >> > >>>>>>>>>>> general for adding new encodings.
> > >> > >>>>>>>>>>>
> > >> > >>>>>>>>>>>
> > >> > >>>>>>>>>> +1
> > >> > >>>>>>>>>>
> > >> > >>>>>>>>>
> > >> > >>>>>>>>
> > >> > >>>>>>>
> > >> > >
> > >> >
> > >> >
> > >> >
> > >>
> > >
> >
>

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