Thanks Steven. This is a very nice point. > The default catalog could also mean a 3rd catalog
Overall, I think we all agree that the register view should only register the existing metadata. If the view is not queryable in the new catalog from Spark (due to the current spec design and how it is integrated with Spark), we can provide a Spark procedure to fix it. Ideally, we should avoid requiring users to do manual maintenance (such as running a procedure). It would be good to revisit the view spec from an interoperability perspective and see whether Spark integration for views can be handled differently to improve interoperability and update the spec accordingly if required (maybe version 2). - Ajantha On Wed, Jan 7, 2026 at 11:47 PM Steven Wu <[email protected]> wrote: > For the following reasons, I am also in favor that registerView doesn't > automatically modify the `default-catalog` field from the source catalog to > the destination catalog > > * There is a major difference between registerTable and registerView. A > table is fully self-contained. A view always references other tables or > views. If the referenced source views and tables haven't been migrated > before the registerView, it is not safe to auto update the catalog name. > * The default catalog could also mean a 3rd catalog. In this case, we > certainly don't want to change the field value. But I guess we can > potentially compare the values to detect this scenario. > * In the MV discussion, there was an extensive debate on the catalog name. > Different setups can use different names for the same catalog, which is > totally a setup problem that Iceberg view spec can't guard against. > > > > On Wed, Jan 7, 2026 at 8:58 AM Ajantha Bhat <[email protected]> wrote: > >> Hi all, I meant the registered view in the new catalog uses the >> `default-catalog` as the old catalog name. Which inturn causes the >> failure to read the view in Spark. So, the discussion was about >> catalog names. Should we update it during register view or from a >> separate procedure. I am in favour of separate procedures. >> >> And thanks Christian for bringing up the java implementation issue >> with `default-namespace` (another field in the spec). We will check if >> the new procedure can also fix that in the existing views and new >> views from Spark can avoid writing like that. >> >> - Ajantha >> >> >> On Wed, Jan 7, 2026 at 10:08 PM Christian Thiel >> <[email protected]> wrote: >> > >> > Hi Ajantha, >> > >> > I agree with your approach - register should not change the >> default-namespace. >> > >> > When we write the routine in spark, we might want to re-visit the use >> of `default-namespace` a bit more thoroughly. While it is a required field >> in the spec, Spark sends an empty array as `default-namespace`. This is >> against the spec which states that a namespace is a `Reference to one or >> more levels of a namespace` - not zero. It also creates cross-language >> problems, as rust is following the spec and returns an error when trying to >> construct a namespace without 0 elements [1]. >> > >> > Best, >> > Christian >> > >> > [1]: >> https://github.com/apache/iceberg-rust/blob/7f2dda3a3807e89b162785b4f16d655ca6b84f79/crates/iceberg/src/catalog/mod.rs#L142-L145 >> > >> > On Wed, 7 Jan 2026 at 09:04, Ajantha Bhat <[email protected]> >> wrote: >> >> >> >> Hi Everyone, >> >> >> >> During implementation of register view, observed that view spec >> captures default namespace. So, once the views are registered from one >> catalog to another, Spark cannot read that view as it still points to the >> old catalog-name as the default namespace. This problem is specific to >> spark integration and we had similar concerns during the spec design. >> >> >> >> I would like to keep the scope of register view limited to just >> registering the existing view to the catalog, similar to register table. >> For updating or fixing the catalog name, we can provide a separate Spark >> procedure. >> >> >> >> I don’t think the register view itself should update the catalog name, >> because that would mean creating a new metadata file and a new version, >> which is not really a register operation. >> >> >> >> Any thoughts on this? >> >> >> >> - Ajantha >> >> >> >> On Wed, Dec 17, 2025 at 9:11 PM Ajantha Bhat <[email protected]> >> wrote: >> >>> >> >>> Here are the PRs: >> >>> >> >>> - API,Core: Support registerView for view catalog #14868 >> >>> - SPEC: Add REST endpoint for registering views #14869 >> >>> - REST: Implement register view for REST catalog #14870 >> >>> >> >>> I will open a separate vote thread for spec change, once the spec PR >> is reviewed. >> >>> >> >>> - Ajantha >> >>> >> >>> On Tue, Dec 16, 2025 at 8:52 AM Kevin Liu <[email protected]> >> wrote: >> >>>> >> >>>> Thanks for the pointer! I missed the Spark page. Tried it out >> locally and wrote some view metadata files. >> >>>> Looking forward to the PR. >> >>>> >> >>>> Best, >> >>>> Kevin Liu >> >>>> >> >>>> >> >>>> On Mon, Dec 15, 2025 at 6:28 PM Ajantha Bhat <[email protected]> >> wrote: >> >>>>>> >> >>>>>> are there any engines currently supporting the view spec? Based on >> my search, I’m not aware of any. >> >>>>> >> >>>>> Hi Kevin, could you clarify what you meant here? The Iceberg View >> Spec has already been officially approved, and the IRC spec is approved as >> well. Both Spark (see docs) and Dremio already support it. Other engine >> users can comment more on their integration. >> >>>>> >> >>>>> >> >>>>>> It might make sense to prioritize view spec adoption first, so we >> have more view metadata JSONs available before adding additional >> view-related functionality to the IRC spec. >> >>>>> >> >>>>> >> >>>>> While broader adoption of the view spec would definitely help, I >> don’t think we should delay adding register view support. Since format >> version 1 is already standardized and in use, we can always introduce >> further improvements in format version 2. >> >>>>> >> >>>>> - Ajantha >> >>>>> >> >>>>> >> >>>>> On Mon, Dec 15, 2025 at 9:32 PM Kevin Liu <[email protected]> >> wrote: >> >>>>>> >> >>>>>> Hi all, >> >>>>>> >> >>>>>> Following up on this, are there any engines currently supporting >> the view spec? Based on my search, I’m not aware of any. >> >>>>>> It might make sense to prioritize view spec adoption first, so we >> have more view metadata JSONs available before adding additional >> view-related functionality to the IRC spec. >> >>>>>> >> >>>>>> Thoughts? >> >>>>>> >> >>>>>> Best regards, >> >>>>>> Kevin Liu >> >>>>>> >> >>>>>> >> >>>>>> On Tue, Dec 9, 2025 at 9:57 PM Ajantha Bhat <[email protected]> >> wrote: >> >>>>>>> >> >>>>>>> Thanks everyone. >> >>>>>>> >> >>>>>>> As there are no additional comments on the proposed solution, >> I’ll move forward with the implementation and share the corresponding PRs >> when they’re ready. >> >>>>>>> >> >>>>>>> - Ajantha >> >>>>>>> >> >>>>>>> On Tue, Dec 2, 2025 at 10:42 PM Kevin Liu <[email protected]> >> wrote: >> >>>>>>>> >> >>>>>>>> That's a good point, Gabor. Catalog servers advertise view >> support through the getConfig (v1/config) response. So a dedicated register >> view endpoint is more explicit. This way also provides separate authz for >> registerView, as Ajantha mentioned. I like this method. >> >>>>>>>> >> >>>>>>>> Just to recap on the above. The 2 other ideas are >> >>>>>>>> - overload the /register endpoint to support view, using an >> optional header param (i.e. view=true) >> >>>>>>>> - overload the /register endpoint to support view; try as table >> first, then fallback to view (similar to the loadTable behavior) >> >>>>>>>> >> >>>>>>>> Best, >> >>>>>>>> Kevin Liu >> >>>>>>>> >> >>>>>>>> >> >>>>>>>> >> >>>>>>>> On Tue, Dec 2, 2025 at 6:56 AM Gábor Kaszab < >> [email protected]> wrote: >> >>>>>>>>> >> >>>>>>>>> Hey All, >> >>>>>>>>> >> >>>>>>>>> +1 for the improvement in general. >> >>>>>>>>> Also, I think it makes sense to make a distinction between >> table endpoints and view endpoints instead of making the register endpoint >> more general. The server could articulate explicitly if such a register >> view endpoint is supported or not when returning the list of supported >> endpoints. If we change the register endpoint to serve both, we won't be >> able to decide simply by looking at the list of endpoints if the server is >> able to register views or not. >> >>>>>>>>> So +1 for a new endpoint. >> >>>>>>>>> >> >>>>>>>>> Cheers, >> >>>>>>>>> Gabor >> >>>>>>>>> >> >>>>>>>>> Jean-Baptiste Onofré <[email protected]> ezt írta (időpont: >> 2025. dec. 2., K, 15:09): >> >>>>>>>>>> >> >>>>>>>>>> Hi Tobias, >> >>>>>>>>>> >> >>>>>>>>>> If it is an optional field in the request body, that would >> also be acceptable to me, provided it does not break existing clients. >> >>>>>>>>>> >> >>>>>>>>>> Regards, >> >>>>>>>>>> JB >> >>>>>>>>>> >> >>>>>>>>>> On Tue, Dec 2, 2025 at 11:33 AM Tobias < >> [email protected]> wrote: >> >>>>>>>>>>> >> >>>>>>>>>>> Hi, >> >>>>>>>>>>> >> >>>>>>>>>>> What speaks against making /register first try the provided >> metadata as a table and then as a view before rejecting as invalid? >> >>>>>>>>>>> >> >>>>>>>>>>> @JB, why would you prefer a header param over an optional >> field `type` in the request? >> >>>>>>>>>>> >> >>>>>>>>>>> Kind regards, >> >>>>>>>>>>> Tobias >> >>>>>>>>>>> >> >>>>>>>>>>> Am Di., 2. Dez. 2025 um 07:45 Uhr schrieb Jean-Baptiste >> Onofré <[email protected]>: >> >>>>>>>>>>>> >> >>>>>>>>>>>> Hi >> >>>>>>>>>>>> >> >>>>>>>>>>>> I agree that registerView makes sense. >> >>>>>>>>>>>> >> >>>>>>>>>>>> Regarding the /register endpoint in the IRC spec, maybe we >> can use a header param (optional) when we want to register a view >> (view=true for instance). >> >>>>>>>>>>>> >> >>>>>>>>>>>> Regards >> >>>>>>>>>>>> JB >> >>>>>>>>>>>> >> >>>>>>>>>>>> On Tue, Dec 2, 2025 at 5:12 AM Kevin Liu < >> [email protected]> wrote: >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> Hi Ajantha, >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> Thanks for bringing this up. I think it's a good idea to be >> able to register views, and by extension, to replicate from one catalog to >> another. >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> The `registerView` function makes sense to me. The IRC >> spec, however, might be a bit more complicated. The "register" endpoint >> (`/v1/{prefix}/namespaces/{namespace}/register`) [1] is currently used to >> register tables only. We could either extend this endpoint to support views >> or create a separate "registerView" endpoint. >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> Would love to hear what others think. >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> Best, >> >>>>>>>>>>>>> Kevin Liu >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> [1] >> https://github.com/apache/iceberg/blob/b35c7ec1b03e3897da68960cd556d635b2f5ae54/open-api/rest-catalog-open-api.yaml#L868 >> >>>>>>>>>>>>> >> >>>>>>>>>>>>> On Tue, Nov 25, 2025 at 2:28 AM Ajantha Bhat < >> [email protected]> wrote: >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Hi everyone, >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Currently, catalogs provide a registerTable function that >> allows registering an existing table with a catalog if it does not already >> exist. This is particularly useful for migrating Iceberg tables between >> catalogs. >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> We have users who are in the process of migrating from one >> catalog to another. While migrating tables works well, migrating views >> remains challenging. One option is to simply recreate the views, since view >> creation is a lightweight operation. However, this approach has two main >> drawbacks: >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Recreating a view loses its version history and original >> metadata. >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Some catalogs may not allow recreating a view if a view >> with the same name already exists in the target location. >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> To address this, I propose adding a registerView >> functionality for completeness. This would enable users to register >> existing views with a catalog, similar to how we register existing tables >> today. >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> As a follow-up, I can open a PR to implement: >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> registerView(TableIdentifier identifier, String >> metadataFileLocation) in ViewCatalog >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Corresponding updates to the Iceberg REST catalog spec >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Necessary API additions >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> Would love to hear your thoughts and feedback on this >> proposal. >> >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> - Ajantha >> >
