lucasfang opened a new issue, #426: URL: https://github.com/apache/paimon-cpp/issues/426
## Search before asking - [x] I searched in the [issues](https://github.com/apache/paimon-cpp/issues) and found nothing similar. ## Motivation Reading a BlobView field resolves the blob table it points at, the dependency table, in `BlobViewLookup::LoadTableDescriptorChunk`. Today that read borrows the file system of the downstream read and passes it down through `CatalogContext`, which causes two problems. The dependency table is authenticated as the downstream table. The file system handed down issues credentials for the table the read started from, not the one about to be read, so a metastore that authorizes per table cannot tell them apart. The Java `CatalogEnvironment.dependencyReadContext()` instead builds a catalog of its own for the dependency table and, on a REST metastore, sends an `X-Paimon-Read-Via` header naming the starting table so the server can authorize the dependency through that table's owner. cpp sends no such header. `BLOB_VIEW_UPSTREAM_WAREHOUSE` is also mandatory: absent it the read fails with `invalid config for blob view`. The lookup then probes two candidate paths, `<db>.db/<table>` and `<db>/<table>`, and reports `Ambiguous table path` when both or neither exist, which a metastore-backed catalog resolves by identifier anyway. ## Solution - In `ReadContextBuilder::Finish`, when the read goes through a catalog naming a table and the metastore is `rest`, add a `header.X-Paimon-Read-Via` option carrying the URL-encoded flat JSON `{"database":...,"object":...}` of the starting identifier, mirroring the Java serializer. An existing value wins so a chain of views reports its outermost one instead of the innermost, and the object name keeps any branch suffix. - Change `CatalogContext` to carry the `fs_scheme_to_identifier_map` instead of a `FileSystem`, and have `BlobViewLookup` create a catalog from those options with a null file system so the dependency table is read under its own credentials. Drop the custom `GetTableLocation` fallback probing in favor of `catalog->GetTableLocation(identifier)` plus `WithCatalog` on the scan and read builders. - Make `BLOB_VIEW_UPSTREAM_WAREHOUSE` optional: absent it, fall back to the warehouse the downstream table itself lives in, stripping its trailing `<db>.db/<table>` components, which resolves a co-located upstream table. ## Anything else? No storage format or protocol change; the `X-Paimon-Read-Via` header matches the Java REST protocol. In `include/paimon/` only the doc comment of `Options::BLOB_VIEW_UPSTREAM_WAREHOUSE` changes, but its behavior changes from required to optional-with-fallback. ## Are you willing to submit a PR? - [x] I'm willing to submit a PR! -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
