Thanks Renjie! The existing spec has some guidance on resolving catalogs on the fly already (to address the case of view text with table identifiers missing the catalog part). The guidance is to use the catalog where the view is stored. But I find this rule hard to interpret or use. The catalog itself is a logical construct—such as a federated catalog that delegates to multiple physical backends (e.g., HMS and REST). In such cases, the catalog (e.g., `my_catalog` in `my_catalog.namespace1.table1`) doesn’t physically store the tables; it only routes requests to underlying stores. Therefore, defaulting identifier resolution based on the catalog where the view is "stored" doesn’t align with how catalogs actually behave in practice.
Thanks, Walaa. On Sun, Apr 20, 2025 at 11:17 PM Renjie Liu <liurenjie2...@gmail.com> wrote: > Hi, Walaa: > > Thanks for the proposal. > > I've reviewed the doc, but in general I have some concerns with resolving > catalog names on the fly with query engine defined catalog names. This > introduces some flexibility at first glance, but also makes > misconfiguration difficult to explain. > > But I agree with one part that we should store resolved table uuid in view > metadata, as table/view renaming may introduce errors that's difficult to > understand for user. > > On Sat, Apr 19, 2025 at 3:02 AM Walaa Eldin Moustafa < > wa.moust...@gmail.com> wrote: > >> Hi Everyone, >> >> Looking forward to keeping up the momentum and closing out the MV spec as >> well. I’m hoping we can proceed to a vote next week. >> >> Here is a summary in case that helps. The proposal outlines a strategy >> for handling table identifiers in Iceberg view metadata, with the goal of >> ensuring correctness, portability, and engine compatibility. It recommends >> resolving table identifiers at read time (late binding) rather than >> creation time, and introduces UUID-based validation to maintain identity >> guarantees across engines, or sessions. It also revises how default-catalog >> and default-namespace are handled (defaulting both to the session context >> if not explicitly set) to better align with engine behavior and improve >> cross-engine interoperability. >> >> Please let me know your thoughts. >> >> Thanks, >> Walaa. >> >> >> >> On Wed, Apr 16, 2025 at 2:03 PM Walaa Eldin Moustafa < >> wa.moust...@gmail.com> wrote: >> >>> Thanks Eduard and Sung! I have addressed the comments. >>> >>> One key point to keep in mind is that catalog names in the spec refer to >>> logical catalogs—i.e., the first part of a three-part identifier. These >>> correspond to Spark's DataSourceV2 catalogs, Trino connectors, and similar >>> constructs. This is a level of abstraction above physical catalogs, which >>> are not referenced or used in the view spec. The reason is that table >>> identifiers in the view definition/text itself refer to logical catalogs, >>> not physical ones (since they interface directly with the engine and not a >>> specific metastore). >>> >>> Thanks, >>> Walaa. >>> >>> >>> On Wed, Apr 16, 2025 at 6:15 AM Sung Yun <sungwy...@gmail.com> wrote: >>> >>>> Thank you Walaa for the proposal. I think view portability is a very >>>> important topic for us to continue discussing as it relies on many >>>> assumptions within the data ecosystem for it to function like you've >>>> highlighted well in the document. >>>> >>>> I've added a few comments around how this may impact the permission >>>> questions the engines will be asking, and whether that is the desired >>>> behavior. >>>> >>>> Sung >>>> >>>> On Wed, Apr 16, 2025 at 7:32 AM Eduard Tudenhöfner < >>>> etudenhoef...@apache.org> wrote: >>>> >>>>> Thanks Walaa for tackling this problem. I've added a few comments to >>>>> get a better understanding of how this will look like in the actual >>>>> implementation. >>>>> >>>>> Eduard >>>>> >>>>> On Tue, Apr 15, 2025 at 7:09 PM Walaa Eldin Moustafa < >>>>> wa.moust...@gmail.com> wrote: >>>>> >>>>>> Hi Everyone, >>>>>> >>>>>> Starting this thread to resume our discussion on how to reference >>>>>> table identifiers from Iceberg metadata, a key aspect of the view >>>>>> specification, particularly in relation to the MV (materialized view) >>>>>> extensions. >>>>>> >>>>>> I had the chance to speak offline with a few community members to >>>>>> better understand how the current spec is being interpreted. Those >>>>>> conversations served as inputs to a new proposal on how table identifier >>>>>> references could be represented in metadata. >>>>>> >>>>>> You can find the proposal here [1]. I look forward to your feedback >>>>>> and working together to move this forward so we can finalize the MV spec >>>>>> as >>>>>> well. >>>>>> >>>>>> [1] >>>>>> https://docs.google.com/document/d/1-I2v_OqBgJi_8HVaeH1u2jowghmXoB8XaJLzPBa_Hg8/edit?tab=t.0 >>>>>> >>>>>> Thanks, >>>>>> Walaa. >>>>>> >>>>>
