waynexia opened a new issue, #6335: URL: https://github.com/apache/arrow-datafusion/issues/6335
### Is your feature request related to a problem or challenge? DataFusion provides good extensibility for user-defined plans and expressions. The extended plan is defined as a branch `LogicalPlan::Extension(_)`, which is based on the trait `UserDefinedLogicalNode`. This ticket requests to add support for such extension plans in substrait. ### Describe the solution you'd like Substrait has defined [User Defined Relations](https://substrait.io/relations/user_defined_relations/) (which is currently a placeholder page..) and in the library it also contains a similar branch [`ExtensionSingleRel`](https://docs.rs/substrait/latest/substrait/proto/struct.ExtensionSingleRel.html) from [`RelType`](https://docs.rs/substrait/latest/substrait/proto/rel/enum.RelType.html). The extension uses protobuf's [`Any`](https://docs.rs/prost-types/0.11.9/prost_types/struct.Any.html) type, which is another raw bytes: ```rust pub struct Any { pub type_url: [String](https://doc.rust-lang.org/nightly/alloc/string/struct.String.html), pub value: [Vec](https://doc.rust-lang.org/nightly/alloc/vec/struct.Vec.html)<[u8](https://doc.rust-lang.org/nightly/std/primitive.u8.html)>, } ``` I propose adding two methods to the `UserDefinedLogicalNode` like the following. But as this interface is widely used I think we have to provide the default implementation to avoid breaking. Another way is to define them in a separate trait like `UserDefinedLogicalNodeSubstraitExt` (ahhh it's too long), and only require this trait on the substrait-related interfaces. ```rust fn to_substrait(&self) -> Result<Vec<u8>, ()>; fn from_substrait(&self, buf: &[u8]) -> Result<Arc<dyn UserDefinedLogicalNode>, ()>; ``` ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- 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: github-unsubscr...@arrow.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
