I agree that it can be helpful to return all level namespaces instead of the current level for some use cases to avoid multiple calls from clients. I had similar requirement <https://github.com/apache/polaris-tools/blob/167e74f952ce4df620dac03b2e1315f44b9c2535/iceberg-catalog-migrator/api/src/main/java/org/apache/polaris/iceberg/catalog/migrator/api/CatalogMigrator.java#L201-L209> before and had to keep custom code from the client side.
The implementation can be a bit cleaner and simplified though. Added comments on the PR. - Ajantha On Wed, May 6, 2026 at 6:35 AM Yuya Ebihara <[email protected]> wrote: > Hi everyone, > > I'd like to propose adding support for recursively listing namespaces in > the REST catalog. > > Trino doesn't support multi-level namespaces, so the Iceberg connector > currently issues requests per namespace and flattens the results. This can > become time-consuming when there are many namespaces or deeply nested > structures. > > I believe this is not specific to Trino. A similar request was raised last > year by the DuckDB community ( > https://github.com/apache/iceberg/issues/13453), although it was closed > due to inactivity. > > I've opened a draft PR that introduces an optional 'recursive' parameter > to the GET /v1/{prefix}/namespaces endpoint: > https://github.com/apache/iceberg/pull/16199 > > I'd appreciate any feedback or suggestions. > > Thanks, > Yuya Ebihara >
