Move array ArrayAgg to a UserDefinedAggregate

datafusion/core/src/dataframe/mod.rs

@@ -1696,10 +1696,10 @@ mod tests {
     use datafusion_common::{Constraint, Constraints, ScalarValue};
     use datafusion_common_runtime::SpawnedTask;
     use datafusion_expr::{
-        array_agg, cast, create_udf, expr, lit, BuiltInWindowFunction,
-        ScalarFunctionImplementation, Volatility, WindowFrame, WindowFunctionDefinition,
+        cast, create_udf, expr, lit, BuiltInWindowFunction, ScalarFunctionImplementation,
+        Volatility, WindowFrame, WindowFunctionDefinition,
     };
-    use datafusion_functions_aggregate::expr_fn::count_distinct;
+    use datafusion_functions_aggregate::expr_fn::{array_agg, count_distinct};
     use datafusion_physical_expr::expressions::Column;
     use datafusion_physical_plan::{get_plan_string, ExecutionPlanProperties};
 

datafusion/core/src/physical_planner.rs

@@ -1839,7 +1839,34 @@ pub fn create_aggregate_expr_with_name_and_maybe_filter(
                 .unwrap_or(sqlparser::ast::NullTreatment::RespectNulls)
                 == NullTreatment::IgnoreNulls;
 
+            // TODO: Remove this after array_agg are all udafs
             let (agg_expr, filter, order_by) = match func_def {
+                AggregateFunctionDefinition::UDF(udf)
+                    if udf.name() == "ARRAY_AGG" && order_by.is_some() =>
+                {
+                    // not yet support UDAF, fallback to builtin
+                    let physical_sort_exprs = match order_by {
+                        Some(exprs) => Some(create_physical_sort_exprs(
+                            exprs,
+                            logical_input_schema,
+                            execution_props,
+                        )?),
+                        None => None,
+                    };
+                    let ordering_reqs: Vec<PhysicalSortExpr> =
+                        physical_sort_exprs.clone().unwrap_or(vec![]);
+                    let fun = aggregates::AggregateFunction::ArrayAgg;
+                    let agg_expr = aggregates::create_aggregate_expr(
+                        &fun,
+                        *distinct,
+                        &physical_args,
+                        &ordering_reqs,
+                        physical_input_schema,
+                        name,
+                        ignore_nulls,
+                    )?;
+                    (agg_expr, filter, physical_sort_exprs)
+                }
                 AggregateFunctionDefinition::BuiltIn(fun) => {
                     let physical_sort_exprs = match order_by {
                         Some(exprs) => Some(create_physical_sort_exprs(
@@ -1888,6 +1915,7 @@ pub fn create_aggregate_expr_with_name_and_maybe_filter(
                     (agg_expr, filter, physical_sort_exprs)
                 }
             };
+
             Ok((agg_expr, filter, order_by))
         }
         other => internal_err!("Invalid aggregate expression '{other:?}'"),

datafusion/core/tests/dataframe/mod.rs

@@ -54,11 +54,11 @@ use datafusion_execution::runtime_env::RuntimeEnv;
 use datafusion_expr::expr::{GroupingSet, Sort};
 use datafusion_expr::var_provider::{VarProvider, VarType};
 use datafusion_expr::{
-    array_agg, cast, col, exists, expr, in_subquery, lit, max, out_ref_col, placeholder,
+    cast, col, exists, expr, in_subquery, lit, max, out_ref_col, placeholder,
     scalar_subquery, when, wildcard, Expr, ExprSchemable, WindowFrame, WindowFrameBound,
     WindowFrameUnits, WindowFunctionDefinition,
 };
-use datafusion_functions_aggregate::expr_fn::{avg, count, sum};
+use datafusion_functions_aggregate::expr_fn::{array_agg, avg, count, sum};
 
 #[tokio::test]
 async fn test_count_wildcard_on_sort() -> Result<()> {
@@ -1389,7 +1389,7 @@ async fn unnest_with_redundant_columns() -> Result<()> {
     let expected = vec![
         "Projection: shapes.shape_id [shape_id:UInt32]",
         "  Unnest: lists[shape_id2] structs[] [shape_id:UInt32, shape_id2:UInt32;N]",
-        "    Aggregate: groupBy=[[shapes.shape_id]], aggr=[[ARRAY_AGG(shapes.shape_id) AS shape_id2]] [shape_id:UInt32, shape_id2:List(Field { name: \"item\", data_type: UInt32, nullable: false, dict_id: 0, dict_is_ordered: false, metadata: {} });N]",
+        "    Aggregate: groupBy=[[shapes.shape_id]], aggr=[[ARRAY_AGG(shapes.shape_id) AS shape_id2]] [shape_id:UInt32, shape_id2:List(Field { name: \"item\", data_type: UInt32, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} });N]",
         "      TableScan: shapes projection=[shape_id] [shape_id:UInt32]",
     ];
 

datafusion/expr/src/expr_fn.rs

@@ -171,6 +171,7 @@ pub fn max(expr: Expr) -> Expr {
     ))
 }
 
+// TODO: remove
 /// Create an expression to represent the array_agg() aggregate function
 pub fn array_agg(expr: Expr) -> Expr {
     Expr::AggregateFunction(AggregateFunction::new(

datafusion/functions-aggregate/src/array_agg.rs

@@ -0,0 +1,249 @@
+// 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.
+
+//! Defines physical expressions that can evaluated at runtime during query execution
+
+use arrow::array::{Array, ArrayRef, AsArray};
+use arrow::datatypes::DataType;
+use arrow_schema::Field;
+
+use datafusion_common::cast::as_list_array;
+use datafusion_common::utils::array_into_list_array_nullable;
+use datafusion_common::Result;
+use datafusion_common::ScalarValue;
+use datafusion_expr::function::{AccumulatorArgs, StateFieldsArgs};
+use datafusion_expr::utils::format_state_name;
+use datafusion_expr::AggregateUDFImpl;
+use datafusion_expr::{Accumulator, Signature, Volatility};
+use std::collections::HashSet;
+use std::sync::Arc;
+
+make_udaf_expr_and_func!(
+    ArrayAgg,
+    array_agg,
+    expression,
+    "input values, including nulls, concatenated into an array",
+    array_agg_udaf
+);
+
+#[derive(Debug)]
+/// ARRAY_AGG aggregate expression
+pub struct ArrayAgg {
+    signature: Signature,
+    alias: Vec<String>,
+}
+
+impl Default for ArrayAgg {
+    fn default() -> Self {
+        Self {
+            signature: Signature::any(1, Volatility::Immutable),
+            alias: vec!["array_agg".to_string()],
+        }
+    }
+}
+
+impl AggregateUDFImpl for ArrayAgg {
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+
+    // TODO: change name to lowercase
+    fn name(&self) -> &str {
+        "ARRAY_AGG"
+    }
+
+    fn aliases(&self) -> &[String] {
+        &self.alias
+    }
+
+    fn signature(&self) -> &Signature {
+        &self.signature
+    }
+
+    fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> {
+        Ok(DataType::List(Arc::new(Field::new(
+            "item",
+            arg_types[0].clone(),
+            true,
+        ))))
+    }
+
+    fn state_fields(&self, args: StateFieldsArgs) -> Result<Vec<Field>> {
+        if args.is_distinct {
+            return Ok(vec![Field::new_list(
+                format_state_name(args.name, "distinct_array_agg"),
+                Field::new("item", args.input_type.clone(), true),
+                true,
+            )]);
+        }
+
+        Ok(vec![Field::new_list(
+            format_state_name(args.name, "array_agg"),
+            Field::new("item", args.input_type.clone(), true),
+            true,
+        )])
+    }
+
+    fn accumulator(&self, acc_args: AccumulatorArgs) -> Result<Box<dyn Accumulator>> {
+        if acc_args.is_distinct {
+            return Ok(Box::new(DistinctArrayAggAccumulator::try_new(
+                acc_args.input_type,
+            )?));
+        }
+
+        Ok(Box::new(ArrayAggAccumulator::try_new(acc_args.input_type)?))
+    }
+}
+
+#[derive(Debug)]
+pub struct ArrayAggAccumulator {
+    values: Vec<ArrayRef>,
+    datatype: DataType,
+}
+
+impl ArrayAggAccumulator {
+    /// new array_agg accumulator based on given item data type
+    pub fn try_new(datatype: &DataType) -> Result<Self> {
+        Ok(Self {
+            values: vec![],
+            datatype: datatype.clone(),
+        })
+    }
+}
+
+impl Accumulator for ArrayAggAccumulator {
+    // Append value like Int64Array(1,2,3)
+    fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()> {
+        if values.is_empty() {
+            return Ok(());
+        }
+        assert!(values.len() == 1, "array_agg can only take 1 param!");
+
+        let val = Arc::clone(&values[0]);
+        if val.len() > 0 {
+            self.values.push(val);
+        }
+        Ok(())
+    }
+
+    // Append value like ListArray(Int64Array(1,2,3), Int64Array(4,5,6))
+    fn merge_batch(&mut self, states: &[ArrayRef]) -> Result<()> {
+        if states.is_empty() {
+            return Ok(());
+        }
+        assert!(states.len() == 1, "array_agg states must be singleton!");
+
+        let list_arr = as_list_array(&states[0])?;
+        for arr in list_arr.iter().flatten() {
+            self.values.push(arr);
+        }
+        Ok(())
+    }
+
+    fn state(&mut self) -> Result<Vec<ScalarValue>> {
+        Ok(vec![self.evaluate()?])
+    }
+
+    fn evaluate(&mut self) -> Result<ScalarValue> {
+        // Transform Vec<ListArr> to ListArr
+        let element_arrays: Vec<&dyn Array> =
+            self.values.iter().map(|a| a.as_ref()).collect();
+
+        if element_arrays.is_empty() {
+            return Ok(ScalarValue::new_null_list(self.datatype.clone(), true, 1));
+        }
+
+        let concated_array = arrow::compute::concat(&element_arrays)?;
+        let list_array = array_into_list_array_nullable(concated_array);
+
+        Ok(ScalarValue::List(Arc::new(list_array)))
+    }
+
+    fn size(&self) -> usize {
+        std::mem::size_of_val(self)
+            + (std::mem::size_of::<ArrayRef>() * self.values.capacity())
+            + self
+                .values
+                .iter()
+                .map(|arr| arr.get_array_memory_size())
+                .sum::<usize>()
+            + self.datatype.size()
+            - std::mem::size_of_val(&self.datatype)
+    }
+}
+
+#[derive(Debug)]
+struct DistinctArrayAggAccumulator {
+    values: HashSet<ScalarValue>,
+    datatype: DataType,
+}
+
+impl DistinctArrayAggAccumulator {
+    pub fn try_new(datatype: &DataType) -> Result<Self> {
+        Ok(Self {
+            values: HashSet::new(),
+            datatype: datatype.clone(),
+        })
+    }
+}
+
+impl Accumulator for DistinctArrayAggAccumulator {
+    fn state(&mut self) -> Result<Vec<ScalarValue>> {
+        Ok(vec![self.evaluate()?])
+    }
+
+    fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()> {
+        assert_eq!(values.len(), 1, "batch input should only include 1 column!");
+
+        let array = &values[0];
+
+        for i in 0..array.len() {
+            let scalar = ScalarValue::try_from_array(&array, i)?;
+            self.values.insert(scalar);
+        }
+
+        Ok(())
+    }
+
+    fn merge_batch(&mut self, states: &[ArrayRef]) -> Result<()> {
+        if states.is_empty() {
+            return Ok(());
+        }
+
+        states[0]
+            .as_list::<i32>()
+            .iter()
+            .flatten()
+            .try_for_each(|val| self.update_batch(&[val]))
+    }
+
+    fn evaluate(&mut self) -> Result<ScalarValue> {
+        let values: Vec<ScalarValue> = self.values.iter().cloned().collect();
+        if values.is_empty() {
+            return Ok(ScalarValue::new_null_list(self.datatype.clone(), true, 1));
+        }
+        let arr = ScalarValue::new_list(&values, &self.datatype, true);
+        Ok(ScalarValue::List(arr))
+    }
+
+    fn size(&self) -> usize {
+        std::mem::size_of_val(self) + ScalarValue::size_of_hashset(&self.values)
+            - std::mem::size_of_val(&self.values)
+            + self.datatype.size()
+            - std::mem::size_of_val(&self.datatype)
+    }
+}

datafusion/functions-aggregate/src/lib.rs

@@ -58,6 +58,7 @@
 pub mod macros;
 
 pub mod approx_distinct;
+pub mod array_agg;
 pub mod correlation;
 pub mod count;
 pub mod covariance;
@@ -93,6 +94,7 @@ pub mod expr_fn {
     pub use super::approx_median::approx_median;
     pub use super::approx_percentile_cont::approx_percentile_cont;
     pub use super::approx_percentile_cont_with_weight::approx_percentile_cont_with_weight;
+    pub use super::array_agg::array_agg;
     pub use super::average::avg;
     pub use super::bit_and_or_xor::bit_and;
     pub use super::bit_and_or_xor::bit_or;
@@ -128,6 +130,7 @@ pub mod expr_fn {
 /// Returns all default aggregate functions
 pub fn all_default_aggregate_functions() -> Vec<Arc<AggregateUDF>> {
     vec![
+        array_agg::array_agg_udaf(),
         first_last::first_value_udaf(),
         first_last::last_value_udaf(),
         covariance::covar_samp_udaf(),
@@ -191,8 +194,9 @@ mod tests {
         let mut names = HashSet::new();
         for func in all_default_aggregate_functions() {
             // TODO: remove this
-            // These functions are in intermediate migration state, skip them
-            if func.name().to_lowercase() == "count" {
+            // These functions are in intermidiate migration state, skip them
+            let name_lower_case = func.name().to_lowercase();
+            if name_lower_case == "count" || name_lower_case == "array_agg" {
                 continue;
             }
             assert!(

datafusion/functions-array/src/planner.rs

@@ -19,8 +19,9 @@
 
 use datafusion_common::{utils::list_ndims, DFSchema, Result};
 use datafusion_expr::{
+    expr::AggregateFunctionDefinition,
     planner::{ExprPlanner, PlannerResult, RawBinaryExpr, RawFieldAccessExpr},
-    sqlparser, AggregateFunction, Expr, ExprSchemable, GetFieldAccess,
+    sqlparser, Expr, ExprSchemable, GetFieldAccess,
 };
 use datafusion_functions::expr_fn::get_field;
 use datafusion_functions_aggregate::nth_value::nth_value_udaf;
@@ -153,8 +154,9 @@ impl ExprPlanner for FieldAccessPlanner {
 }
 
 fn is_array_agg(agg_func: &datafusion_expr::expr::AggregateFunction) -> bool {
-    agg_func.func_def
-        == datafusion_expr::expr::AggregateFunctionDefinition::BuiltIn(
-            AggregateFunction::ArrayAgg,
-        )
+    if let AggregateFunctionDefinition::UDF(udf) = &agg_func.func_def {
+        return udf.name() == "ARRAY_AGG";
+    }
+
+    false
 }