Convert ntile builtIn function to UDWF

datafusion/expr/src/built_in_window_function.rs

@@ -40,8 +40,6 @@ impl fmt::Display for BuiltInWindowFunction {
 /// [Window Function]: https://en.wikipedia.org/wiki/Window_function_(SQL)
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Hash, EnumIter)]
 pub enum BuiltInWindowFunction {
-    /// Integer ranging from 1 to the argument value, dividing the partition as equally as possible
-    Ntile,
     /// returns value evaluated at the row that is the first row of the window frame
     FirstValue,
     /// Returns value evaluated at the row that is the last row of the window frame
@@ -54,7 +52,6 @@ impl BuiltInWindowFunction {
     pub fn name(&self) -> &str {
         use BuiltInWindowFunction::*;
         match self {
-            Ntile => "NTILE",
             FirstValue => "first_value",
             LastValue => "last_value",
             NthValue => "NTH_VALUE",
@@ -66,7 +63,6 @@ impl FromStr for BuiltInWindowFunction {
     type Err = DataFusionError;
     fn from_str(name: &str) -> Result<BuiltInWindowFunction> {
         Ok(match name.to_uppercase().as_str() {
-            "NTILE" => BuiltInWindowFunction::Ntile,
             "FIRST_VALUE" => BuiltInWindowFunction::FirstValue,
             "LAST_VALUE" => BuiltInWindowFunction::LastValue,
             "NTH_VALUE" => BuiltInWindowFunction::NthValue,
@@ -97,7 +93,6 @@ impl BuiltInWindowFunction {
             })?;
 
         match self {
-            BuiltInWindowFunction::Ntile => Ok(DataType::UInt64),
             BuiltInWindowFunction::FirstValue
             | BuiltInWindowFunction::LastValue
             | BuiltInWindowFunction::NthValue => Ok(input_expr_types[0].clone()),
@@ -111,20 +106,6 @@ impl BuiltInWindowFunction {
             BuiltInWindowFunction::FirstValue | BuiltInWindowFunction::LastValue => {
                 Signature::any(1, Volatility::Immutable)
             }
-            BuiltInWindowFunction::Ntile => Signature::uniform(
-                1,
-                vec![
-                    DataType::UInt64,
-                    DataType::UInt32,
-                    DataType::UInt16,
-                    DataType::UInt8,
-                    DataType::Int64,
-                    DataType::Int32,
-                    DataType::Int16,
-                    DataType::Int8,
-                ],
-                Volatility::Immutable,
-            ),
             BuiltInWindowFunction::NthValue => Signature::any(2, Volatility::Immutable),
         }
     }

datafusion/expr/src/expr.rs

@@ -2567,18 +2567,9 @@ mod test {
         Ok(())
     }
 
-    #[test]
-    fn test_ntile_return_type() -> Result<()> {
-        let fun = find_df_window_func("ntile").unwrap();
-        let observed = fun.return_type(&[DataType::Int16], &[true], "")?;
-        assert_eq!(DataType::UInt64, observed);
-
-        Ok(())
-    }
-
     #[test]
     fn test_window_function_case_insensitive() -> Result<()> {
-        let names = vec!["ntile", "first_value", "last_value", "nth_value"];
+        let names = vec!["first_value", "last_value", "nth_value"];
         for name in names {
             let fun = find_df_window_func(name).unwrap();
             let fun2 = find_df_window_func(name.to_uppercase().as_str()).unwrap();

datafusion/expr/src/window_function.rs

@@ -17,11 +17,6 @@
 
 use crate::{expr::WindowFunction, BuiltInWindowFunction, Expr, Literal};
 
-/// Create an expression to represent the `ntile` window function
-pub fn ntile(arg: Expr) -> Expr {
-    Expr::WindowFunction(WindowFunction::new(BuiltInWindowFunction::Ntile, vec![arg]))
-}
-
 /// Create an expression to represent the `nth_value` window function
 pub fn nth_value(arg: Expr, n: i64) -> Expr {
     Expr::WindowFunction(WindowFunction::new(

datafusion/functions-window/src/lib.rs

@@ -34,7 +34,7 @@ pub mod macros;
 
 pub mod cume_dist;
 pub mod lead_lag;
-
+pub mod ntile;
 pub mod rank;
 pub mod row_number;
 mod utils;
@@ -44,6 +44,7 @@ pub mod expr_fn {
     pub use super::cume_dist::cume_dist;
     pub use super::lead_lag::lag;
     pub use super::lead_lag::lead;
+    pub use super::ntile::ntile;
     pub use super::rank::{dense_rank, percent_rank, rank};
     pub use super::row_number::row_number;
 }
@@ -58,6 +59,7 @@ pub fn all_default_window_functions() -> Vec<Arc<WindowUDF>> {
         rank::rank_udwf(),
         rank::dense_rank_udwf(),
         rank::percent_rank_udwf(),
+        ntile::ntile_udwf(),
     ]
 }
 /// Registers all enabled packages with a [`FunctionRegistry`]

datafusion/functions-window/src/ntile.rs

@@ -0,0 +1,168 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! `ntile` window function implementation
+
+use std::any::Any;
+use std::fmt::Debug;
+use std::sync::{Arc, OnceLock};
+
+use crate::utils::{
+    get_scalar_value_from_args, get_signed_integer, get_unsigned_integer,
+};
+use datafusion_common::arrow::array::{ArrayRef, UInt64Array};
+use datafusion_common::arrow::datatypes::{DataType, Field};
+use datafusion_common::{exec_err, DataFusionError, Result};
+use datafusion_expr::window_doc_sections::DOC_SECTION_RANKING;
+use datafusion_expr::{
+    Documentation, Expr, PartitionEvaluator, Signature, Volatility, WindowUDFImpl,
+};
+use datafusion_functions_window_common::field;
+use datafusion_functions_window_common::partition::PartitionEvaluatorArgs;
+use field::WindowUDFFieldArgs;
+
+get_or_init_udwf!(
+    Ntile,
+    ntile,
+    "integer ranging from 1 to the argument value, dividing the partition as equally as possible"
+);
+
+pub fn ntile(arg: Expr) -> Expr {
+    ntile_udwf().call(vec![arg])
+}
+
+#[derive(Debug)]
+pub struct Ntile {
+    signature: Signature,
+}
+
+impl Ntile {
+    /// Create a new `ntile` function
+    pub fn new() -> Self {
+        Self {
+            signature: Signature::uniform(
+                1,
+                vec![
+                    DataType::UInt64,
+                    DataType::UInt32,
+                    DataType::UInt16,
+                    DataType::UInt8,
+                    DataType::Int64,
+                    DataType::Int32,
+                    DataType::Int16,
+                    DataType::Int8,
+                ],
+                Volatility::Immutable,
+            ),
+        }
+    }
+}
+
+impl Default for Ntile {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+static DOCUMENTATION: OnceLock<Documentation> = OnceLock::new();
+
+fn get_ntile_doc() -> &'static Documentation {
+    DOCUMENTATION.get_or_init(|| {
+        Documentation::builder()
+            .with_doc_section(DOC_SECTION_RANKING)
+            .with_description(
+                "Integer ranging from 1 to the argument value, dividing the partition as equally as possible",
+            )
+            .with_syntax_example("ntile(expression)")
+            .with_argument("expression","An integer describing the number groups the partition should be split into")
+            .build()
+            .unwrap()
+    })
+}
+
+impl WindowUDFImpl for Ntile {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn name(&self) -> &str {
+        "ntile"
+    }
+
+    fn signature(&self) -> &Signature {
+        &self.signature
+    }
+
+    fn partition_evaluator(
+        &self,
+        partition_evaluator_args: PartitionEvaluatorArgs,
+    ) -> Result<Box<dyn PartitionEvaluator>> {
+        let scalar_n =
+            get_scalar_value_from_args(partition_evaluator_args.input_exprs(), 0)?
+                .ok_or_else(|| {
+                    DataFusionError::Execution(
+                        "NTILE requires a positive integer".to_string(),
+                    )
+                })?;
+
+        if scalar_n.is_null() {
+            return exec_err!("NTILE requires a positive integer, but finds NULL");
+        }
+
+        if scalar_n.is_unsigned() {
+            let n = get_unsigned_integer(scalar_n)?;
+            Ok(Box::new(NtileEvaluator { n }))
+        } else {
+            let n: i64 = get_signed_integer(scalar_n)?;
+            if n <= 0 {
+                return exec_err!("NTILE requires a positive integer");
+            }
+            Ok(Box::new(NtileEvaluator { n: n as u64 }))
+        }
+    }
+    fn field(&self, field_args: WindowUDFFieldArgs) -> Result<Field> {
+        let nullable = false;
+
+        Ok(Field::new(field_args.name(), DataType::UInt64, nullable))
+    }
+
+    fn documentation(&self) -> Option<&Documentation> {
+        Some(get_ntile_doc())
+    }
+}
+
+#[derive(Debug)]
+struct NtileEvaluator {
+    n: u64,
+}
+
+impl PartitionEvaluator for NtileEvaluator {
+    fn evaluate_all(
+        &mut self,
+        _values: &[ArrayRef],
+        num_rows: usize,
+    ) -> Result<ArrayRef> {
+        let num_rows = num_rows as u64;
+        let mut vec: Vec<u64> = Vec::new();
+        let n = u64::min(self.n, num_rows);
+        for i in 0..num_rows {
+            let res = i * n / num_rows;
+            vec.push(res + 1)
+        }
+        Ok(Arc::new(UInt64Array::from(vec)))
+    }
+}

datafusion/functions-window/src/utils.rs

@@ -51,3 +51,15 @@ pub(crate) fn get_scalar_value_from_args(
         None
     })
 }
+
+pub(crate) fn get_unsigned_integer(value: ScalarValue) -> Result<u64> {
+    if value.is_null() {
+        return Ok(0);
+    }
+
+    if !value.data_type().is_integer() {
+        return exec_err!("Expected an integer value");
+    }
+
+    value.cast_to(&DataType::UInt64)?.try_into()
+}

datafusion/physical-expr/src/expressions/mod.rs

@@ -36,7 +36,6 @@ mod unknown_column;
 /// Module with some convenient methods used in expression building
 pub use crate::aggregate::stats::StatsType;
 pub use crate::window::nth_value::NthValue;
-pub use crate::window::ntile::Ntile;
 pub use crate::PhysicalSortExpr;
 
 pub use binary::{binary, similar_to, BinaryExpr};

datafusion/physical-expr/src/window/mod.rs

@@ -19,7 +19,6 @@ mod aggregate;
 mod built_in;
 mod built_in_window_function_expr;
 pub(crate) mod nth_value;
-pub(crate) mod ntile;
 mod sliding_aggregate;
 mod window_expr;