Thanks, Jan, for the update, and Walaa and Marius for the PoC implementations. I'm excited that we are getting close.
Here is my take regarding the format version. We don't have a dedicated MV spec, which is essentially a combination of view and table specs. It is odd to introduce "materialized-view-format-version" in the view spec. If we introduce any non-compatible changes for MV, we can just bump up the view or table spec version (or both). On Fri, Sep 18, 2026 at 12:08 PM Walaa Eldin Moustafa <[email protected]> wrote: > Thanks, Jan. It’s great to see the spec coming together, and I think > we’re getting quite close to starting the voting process. > > As discussed in our community sync, the plan is to have one final > discussion at the next sync on October 1 and then move to a vote. I’d > like to echo Jan’s request for everyone to take another look at the > spec and share any remaining feedback before then. > > Thanks, > Walaa > > On Fri, Sep 18, 2026 at 7:11 AM Jan Kaul via dev <[email protected]> > wrote: > > > > Hi all, > > > > we've made considerable progress with the Iceberg Materialized View > > Spec. Marius Grama and Walaa Eldin Moustafa have created POC > > implementation of Materialized Views in Spark and Trino to test the > > proposed Spec. You can find them here: > > > > Spark: https://github.com/apache/iceberg/pull/9830 > > > > Trino: https://github.com/trinodb/trino/pull/31027 > > > > > > The POCs proves that the current specification is sound and provides the > > necessary functionality for implementations. > > > > If you're interested, I invite you to have another look at the spec > > again: https://github.com/apache/iceberg/pull/11041 > > > > > > There is also another open question: Should we introduce an equivalence > > of the "format-version" field for Materialized Views similar to the > > Table and View Spec. Generally, it would be desirable to be able to > > evolve the Spec independently. However, currently MVs are designed as an > > extension to the View Spec and is thus closely coupled. So it's not > > entirely clear how this should look like. One option would be to a > > "materialized-view-format-version" field to the View Spec. I would be > > interested in your opinion. > > > > > > Have a great weekend. Best regards, > > > > Jan > > >
