Add user_defined_sql_planners(..) to FunctionRegistry

datafusion/core/src/execution/context/mod.rs

@@ -1392,6 +1392,10 @@ impl FunctionRegistry for SessionContext {
         self.state.write().register_function_rewrite(rewrite)
     }
 
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+        self.state.read().expr_planners()
+    }
+
     fn register_user_defined_sql_planner(
         &mut self,
         user_defined_sql_planner: Arc<dyn UserDefinedSQLPlanner>,

datafusion/core/src/execution/session_state.rs

@@ -1183,6 +1183,10 @@ impl FunctionRegistry for SessionState {
         Ok(())
     }
 
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+        self.user_defined_sql_planners.clone()
+    }
+
     fn register_user_defined_sql_planner(
         &mut self,
         user_defined_sql_planner: Arc<dyn UserDefinedSQLPlanner>,

datafusion/core/tests/user_defined/user_defined_scalar_functions.rs

@@ -571,6 +571,17 @@ async fn test_user_defined_functions_cast_to_i64() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn test_user_defined_sql_functions() -> Result<()> {
+    let ctx = SessionContext::new();
+
+    let sql_planners = ctx.expr_planners();
+
+    assert!(!sql_planners.is_empty());
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn deregister_udf() -> Result<()> {
     let cast2i64 = ScalarUDF::from(CastToI64UDF::new());

datafusion/execution/src/task.rs

@@ -20,15 +20,15 @@ use std::{
     sync::Arc,
 };
 
-use datafusion_common::{plan_datafusion_err, DataFusionError, Result};
-use datafusion_expr::{AggregateUDF, ScalarUDF, WindowUDF};
-
 use crate::{
     config::SessionConfig,
     memory_pool::MemoryPool,
     registry::FunctionRegistry,
     runtime_env::{RuntimeConfig, RuntimeEnv},
 };
+use datafusion_common::{plan_datafusion_err, DataFusionError, Result};
+use datafusion_expr::planner::UserDefinedSQLPlanner;
+use datafusion_expr::{AggregateUDF, ScalarUDF, WindowUDF};
 
 /// Task Execution Context
 ///
@@ -191,6 +191,10 @@ impl FunctionRegistry for TaskContext {
         });
         Ok(self.scalar_functions.insert(udf.name().into(), udf))
     }
+
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+        vec![]
+    }
 }
 
 #[cfg(test)]

datafusion/expr/src/registry.rs

@@ -110,6 +110,9 @@ pub trait FunctionRegistry {
         not_impl_err!("Registering FunctionRewrite")
     }
 
+    /// Set of all registered [`UserDefinedSQLPlanner`]s
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>>;
+
     /// Registers a new [`UserDefinedSQLPlanner`] with the registry.
     fn register_user_defined_sql_planner(
         &mut self,
@@ -192,4 +195,8 @@ impl FunctionRegistry for MemoryFunctionRegistry {
     fn register_udwf(&mut self, udaf: Arc<WindowUDF>) -> Result<Option<Arc<WindowUDF>>> {
         Ok(self.udwfs.insert(udaf.name().into(), udaf))
     }
+
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+        vec![]
+    }
 }

datafusion/proto/src/bytes/mod.rs

@@ -39,6 +39,7 @@ use std::sync::Arc;
 use datafusion::execution::registry::FunctionRegistry;
 use datafusion::physical_plan::ExecutionPlan;
 use datafusion::prelude::SessionContext;
+use datafusion_expr::planner::UserDefinedSQLPlanner;
 
 mod registry;
 
@@ -165,6 +166,10 @@ impl Serializeable for Expr {
                     "register_udwf called in Placeholder Registry!"
                 )
             }
+
+            fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+                vec![]
+            }
         }
         Expr::from_bytes_with_registry(&bytes, &PlaceHolderRegistry)?;
 

datafusion/proto/src/bytes/registry.rs

@@ -20,6 +20,7 @@ use std::{collections::HashSet, sync::Arc};
 use datafusion::execution::registry::FunctionRegistry;
 use datafusion_common::plan_err;
 use datafusion_common::Result;
+use datafusion_expr::planner::UserDefinedSQLPlanner;
 use datafusion_expr::{AggregateUDF, ScalarUDF, WindowUDF};
 
 /// A default [`FunctionRegistry`] registry that does not resolve any
@@ -54,4 +55,8 @@ impl FunctionRegistry for NoRegistry {
     fn register_udwf(&mut self, udwf: Arc<WindowUDF>) -> Result<Option<Arc<WindowUDF>>> {
         plan_err!("No function registry provided to deserialize, so can not deserialize User Defined Window Function '{}'", udwf.inner().name())
     }
+
+    fn expr_planners(&self) -> Vec<Arc<dyn UserDefinedSQLPlanner>> {
+        vec![]
+    }
 }