> """ > Readers need a simple mechanism to know whether they support all > features they may encounter when reading a specific file. > """ > > I would like to dispute this. No argument is given as to why readers > need something else than what is already embodied in the metadata.
Antoine, In my mind, the core usecase is actually knowing how to configure the writer (aka how can a writer have confidence to use a certain parquet feature and make sure the readers they care about can read the file) Andrew On Wed, Sep 2, 2026 at 12:42 PM Antoine Pitrou <[email protected]> wrote: > > """ > Readers need a simple mechanism to know whether they support all > features they may encounter when reading a specific file. > """ > > I would like to dispute this. No argument is given as to why readers > need something else than what is already embodied in the metadata. > > It's also not obvious why that information is granular enough (some > features are optional, the user may not want to read all columns anyway, > etc.). > > At least in Arrow, I don't remember a single user complaining that they > don't have a simpler access to that information. > > Regards > > Antoine. > > > > Le 14/08/2026 à 20:25, Julien Le Dem a écrit : > > Following up on the discussion during the Parquet sync on Wednesday, I > have > > added a new tab to the Versioning document > > < > https://docs.google.com/document/d/19bOTy1WcLs9NP88DrysG4wG50pM6gmIFaSEWzkxUeJw/edit?tab=t.nywy9gjvpwqf > > > > to discuss 4 remaining decision points for the implementation. For each I > > have listed options and pros and cons. > > 1. Mechanism to decide what Parquet features writers should use > > 2. Mechanism to write Parquet files that use a preview feature > > 3. Mechanism to record in the file what features it uses > > 4. Describing reader behavior when reading a file that is not fully > > supported > > > > The stated guiding principle is: We want to minimize prescribing how > > readers and writers should work and focus on giving them the information > to > > implement the behavior they deem appropriate. > > > > Please comment in the doc to help finalize consensus. > > (thank you Andrew for early feedback and helping me think this through!) > > >
