Hi team, There was a request from a few folks, Antoine Pitrou and Adam Reeve if I remember correctly, to perform the experiment on some of the papers that talked about BYTE_STREAM_SPLIT for completeness. I wanted to share the numbers for the same in this sheet. At this point we have numbers on a wide variety of data. (Will have to share the sheet from my snowflake account as our laptops have fair bit of restriction with respect to copy paste permissions :) )
Best Prateek On Thu, Nov 20, 2025 at 2:25 PM PRATEEK GAUR <[email protected]> wrote: > Hi Julien, > > Yes based on > > - Numbers presented > - Discussions over the doc and > - Multiple discussions in the biweekly meeting > > We are in a stage where we agree this is the right encoding to add and we > can move to the DRAFT/POC stage from DISCUSS stage. > Will start working on the PR for the same. > > Thanks for bringing this up. > Prateek > > On Thu, Nov 20, 2025 at 8:16 AM Julien Le Dem <[email protected]> wrote: > >> @PRATEEK GAUR <[email protected]> : Would you agree that we are past >> the DISCUSS step and into the DRAFT/POC phase according to the proposals >> process <https://github.com/apache/parquet-format/tree/master/proposals>? >> If yes, could you open a PR on this page to add this proposal to the list? >> https://github.com/apache/parquet-format/tree/master/proposals >> Thank you! >> >> >> On Thu, Oct 30, 2025 at 2:38 PM Andrew Lamb <[email protected]> >> wrote: >> >> > I have filed a ticket[1] in arrow-rs to track prototyping ALP in the >> Rust >> > Parquet reader if anyone is interested >> > >> > Andrew >> > >> > [1]: https://github.com/apache/arrow-rs/issues/8748 >> > >> > On Wed, Oct 22, 2025 at 1:33 PM Micah Kornfield <[email protected]> >> > wrote: >> > >> > > > >> > > > C++, Java and Rust support them for sure. I feel like we should >> > > > probably default to V2 at some point. >> > > >> > > >> > > I seem to recall, some of the vectorized java readers (Iceberg, Spark) >> > > might not support V2 data pages (but I might be confusing this with >> > > encodings). But this is only a vague recollection. >> > > >> > > >> > > >> > > On Wed, Oct 22, 2025 at 6:38 AM Andrew Lamb <[email protected]> >> > > wrote: >> > > >> > > > > Someone has to add V2 data pages to >> > > > > >> > > > >> > > > >> > > >> > >> https://github.com/apache/parquet-site/blob/production/content/en/docs/File%20Format/implementationstatus.md >> > > > > :) >> > > > >> > > > Your wish is my command: >> > https://github.com/apache/parquet-site/pull/124 >> > > > >> > > > As the format grows in popularity and momentum builds to evolve, I >> feel >> > > the >> > > > content on the parquet.apache.org site could use refreshing / >> > updating. >> > > > So, while I had the site open, I made some other PRs to scratch >> various >> > > > itches >> > > > >> > > > (I am absolutely 🎣 for someone to please review 🙏): >> > > > >> > > > 1. Add Variant/Geometry/Geography types to implementation status >> > matrix: >> > > > https://github.com/apache/parquet-site/pull/123 >> > > > 2. Improve introduction / overview, add more links to spec and >> > > > implementation status: >> https://github.com/apache/parquet-site/pull/125 >> > > > >> > > > >> > > > Thanks, >> > > > Andrew >> > > > >> > > > On Wed, Oct 22, 2025 at 4:09 AM Antoine Pitrou <[email protected]> >> > > wrote: >> > > > >> > > > > >> > > > > Hi Julien, hi all, >> > > > > >> > > > > On Mon, 20 Oct 2025 15:14:58 -0700 >> > > > > Julien Le Dem <[email protected]> wrote: >> > > > > > >> > > > > > Another question from me: >> > > > > > >> > > > > > Since the goal is to not use compression at all in this case (no >> > > ZSTD) >> > > > > > I'm assuming we would be using either: >> > > > > > - the Data Page V1 with UNCOMPRESSED in the >> ColumnMetadata.column >> > > > > > < >> > > > > >> > > > >> > > >> > >> https://github.com/apache/parquet-format/blob/786142e26740487930ddc3ec5e39d780bd930907/src/main/thrift/parquet.thrift#L887 >> > > > > > >> > > > > > field. >> > > > > > - the Data Page V2 with false in the >> DataPageHeaderV2.is_compressed >> > > > > > < >> > > > > >> > > > >> > > >> > >> https://github.com/apache/parquet-format/blob/786142e26740487930ddc3ec5e39d780bd930907/src/main/thrift/parquet.thrift#L746 >> > > > > > >> > > > > > field >> > > > > > The second helping decide if we can selectively compress some >> pages >> > > if >> > > > > they >> > > > > > are less compressed by the >> > > > > > A few years ago there was a question on the support of the >> > > DATA_PAGE_V2 >> > > > > and >> > > > > > I was curious to hear a refresh on how that's generally >> supported >> > in >> > > > > > Parquet implementations. The is_compressed field was exactly >> > intended >> > > > to >> > > > > > avoid block compression when the encoding itself is good enough. >> > > > > >> > > > > Someone has to add V2 data pages to >> > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/apache/parquet-site/blob/production/content/en/docs/File%20Format/implementationstatus.md >> > > > > :) >> > > > > >> > > > > C++, Java and Rust support them for sure. I feel like we should >> > > > > probably default to V2 at some point. >> > > > > >> > > > > Also see https://github.com/apache/parquet-java/issues/3344 for >> > Java. >> > > > > >> > > > > Regards >> > > > > >> > > > > Antoine. >> > > > > >> > > > > >> > > > > > >> > > > > > Julien >> > > > > > >> > > > > > On Mon, Oct 20, 2025 at 11:57 AM Andrew Lamb >> > > > > <[email protected]> wrote: >> > > > > > >> > > > > > > Thanks again Prateek and co for pushing this along! >> > > > > > > >> > > > > > > >> > > > > > > > 1. Design and write our own Parquet-ALP spec so that >> > > > implementations >> > > > > > > > know exactly how to encode and represent data >> > > > > > > >> > > > > > > 100% agree with this (similar to what was done for >> > ParquetVariant) >> > > > > > > >> > > > > > > > 2. I may be missing something, but the paper doesn't seem to >> > > > > mention >> > > > > > > non-finite values (such as +/-Inf and NaNs). >> > > > > > > >> > > > > > > I think they are handled via the "Exception" mechanism. >> Vortex's >> > > ALP >> > > > > > > implementation (below) does appear to handle finite numbers[2] >> > > > > > > >> > > > > > > > 3. It seems there is a single implementation, which is the >> one >> > > > > published >> > > > > > > > together with the paper. It is not obvious that it will be >> > > > > > > > maintained in the future, and reusing it is probably not an >> > > option >> > > > > for >> > > > > > > > non-C++ Parquet implementations >> > > > > > > >> > > > > > > My understanding from the call was that Prateek and team >> > > > re-implemented >> > > > > > > ALP (did not use the implementation from CWI[3]) but that >> would >> > be >> > > > > good to >> > > > > > > confirm. >> > > > > > > >> > > > > > > There is also a Rust implementation of ALP[1] that is part of >> the >> > > > > Vortex >> > > > > > > file format implementation. I have not reviewed it to see if >> it >> > > > > deviates >> > > > > > > from the algorithm presented in the paper. >> > > > > > > >> > > > > > > Andrew >> > > > > > > >> > > > > > > [1]: >> > > > > > > >> > > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/vortex-data/vortex/blob/534821969201b91985a8735b23fc0c415a425a56/encodings/alp/src/lib.rs >> > > > > > > [2]: >> > > > > > > >> > > > > > > >> > > > > >> > > > >> > > >> > >> https://github.com/vortex-data/vortex/blob/534821969201b91985a8735b23fc0c415a425a56/encodings/alp/src/alp/compress.rs#L266-L281 >> > > > > > > [3]: https://github.com/cwida/ALP >> > > > > > > >> > > > > > > >> > > > > > > On Mon, Oct 20, 2025 at 4:47 AM Antoine Pitrou >> > > > > <[email protected]> wrote: >> > > > > > > >> > > > > > > > >> > > > > > > > Hello, >> > > > > > > > >> > > > > > > > Thanks for doing this and I agree the numbers look >> impressive. >> > > > > > > > >> > > > > > > > I would ask if possible for more data points: >> > > > > > > > >> > > > > > > > 1. More datasets: you could for example look at the datasets >> > that >> > > > > were >> > > > > > > > used to originally evalute BYTE_STREAM_SPLIT (see >> > > > > > > > https://issues.apache.org/jira/browse/PARQUET-1622 and >> > > > specifically >> > > > > > > > the Google Doc linked there) >> > > > > > > > >> > > > > > > > 2. Comparison to BYTE_STREAM_SPLIT + LZ4 and >> BYTE_STREAM_SPLIT >> > + >> > > > ZSTD >> > > > > > > > >> > > > > > > > 3. Optionally, some perf numbers on x86 too, but I expect >> that >> > > ALP >> > > > > will >> > > > > > > > remain very good there as well >> > > > > > > > >> > > > > > > > >> > > > > > > > I also have the following reservations towards ALP: >> > > > > > > > >> > > > > > > > 1. There is no published official spec AFAICT, just a >> research >> > > > paper. >> > > > > > > > >> > > > > > > > 2. I may be missing something, but the paper doesn't seem to >> > > > mention >> > > > > > > > non-finite values (such as +/-Inf and NaNs). >> > > > > > > > >> > > > > > > > 3. It seems there is a single implementation, which is the >> one >> > > > > published >> > > > > > > > together with the paper. It is not obvious that it will be >> > > > > > > > maintained in the future, and reusing it is probably not an >> > > option >> > > > > for >> > > > > > > > non-C++ Parquet implementations >> > > > > > > > >> > > > > > > > 4. The encoding itself is complex, since it involves a >> fallback >> > > on >> > > > > > > > another encoding if the primary encoding (which constitutes >> the >> > > > real >> > > > > > > > innovation) doesn't work out on a piece of data. >> > > > > > > > >> > > > > > > > >> > > > > > > > Based on this, I would say that if we think ALP is >> attractive >> > for >> > > > us, >> > > > > > > > we may want to incorporate our own version of ALP with the >> > > > following >> > > > > > > > changes: >> > > > > > > > >> > > > > > > > 1. Design and write our own Parquet-ALP spec so that >> > > > implementations >> > > > > > > > know exactly how to encode and represent data >> > > > > > > > >> > > > > > > > 2. Do not include the ALPrd fallback which is a homegrown >> > > > dictionary >> > > > > > > > encoding without dictionary reuse accross pages, and instead >> > rely >> > > > on >> > > > > a >> > > > > > > > well-known Parquet encoding (such as BYTE_STREAM_SPLIT?) >> > > > > > > > >> > > > > > > > 3. Replace the FOR encoding inside ALP, which aims at >> > compressing >> > > > > > > > integers efficiently, with our own DELTA_BINARY_PACKED >> (which >> > has >> > > > the >> > > > > > > > same qualities and is already available in Parquet >> > > implementations) >> > > > > > > > >> > > > > > > > Regards >> > > > > > > > >> > > > > > > > Antoine. >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > On Thu, 16 Oct 2025 14:47:33 -0700 >> > > > > > > > PRATEEK GAUR <[email protected]> wrote: >> > > > > > > > > Hi team, >> > > > > > > > > >> > > > > > > > > We spent some time evaluating ALP compression and >> > decompression >> > > > > > > compared >> > > > > > > > to >> > > > > > > > > other encoding alternatives like CHIMP/GORILLA and >> > compression >> > > > > > > techniques >> > > > > > > > > like SNAPPY/LZ4/ZSTD. We presented these numbers to the >> > > community >> > > > > > > members >> > > > > > > > > on October 15th in the biweekly parquet meeting. ( I can't >> > seem >> > > > > to >> > > > > > > access >> > > > > > > > > the recording, so please let me know what access rules I >> need >> > > to >> > > > > get to >> > > > > > > > be >> > > > > > > > > able to view it ) >> > > > > > > > > >> > > > > > > > > We did this evaluation over some datasets pointed by the >> ALP >> > > > paper >> > > > > and >> > > > > > > > some >> > > > > > > > > pointed by the parquet community. >> > > > > > > > > >> > > > > > > > > The results are available in the following document >> > > > > > > > > < >> > > > > > > > >> > > > > > > >> > > > > >> > > > >> > > >> > >> https://docs.google.com/document/d/1PlyUSfqCqPVwNt8XA-CfRqsbc0NKRG0Kk1FigEm3JOg/edit?tab=t.0 >> > > > > >> > > > > > > > > >> > > > > > > > > : >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > >> > > > >> > > >> > >> https://docs.google.com/document/d/1PlyUSfqCqPVwNt8XA-CfRqsbc0NKRG0Kk1FigEm3JOg >> > > > > >> > > > > > > > > >> > > > > > > > > Based on the numbers we see >> > > > > > > > > >> > > > > > > > > - ALP is comparable to ZSTD(level=1) in terms of >> > > compression >> > > > > ratio >> > > > > > > > and >> > > > > > > > > much better compared to other schemes. (numbers in the >> > sheet >> > > > > are >> > > > > > > bytes >> > > > > > > > > needed to encode each value ) >> > > > > > > > > - ALP going quite well in terms of decompression speed >> > > > (numbers >> > > > > in >> > > > > > > the >> > > > > > > > > sheet are bytes decompressed per second) >> > > > > > > > > >> > > > > > > > > As next steps we will >> > > > > > > > > >> > > > > > > > > - Get the numbers for compression on top of byte stream >> > > split. >> > > > > > > > > - Evaluate the algorithm over a few more datasets. >> > > > > > > > > - Have an implementation in the arrow-parquet repo. >> > > > > > > > > >> > > > > > > > > Looking forward to feedback from the community. >> > > > > > > > > >> > > > > > > > > Best >> > > > > > > > > Prateek and Dhirhan >> > > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > >> > > >> > >> >
