Reuse fixed-width storage for decimal arrays

Signed-off-by: Connor Tsui <connor.tsui20@gmail.com>

Author: connortsui20

fuzz/src/array/fill_null.rs

@@ -13,6 +13,7 @@ use vortex_array::arrays::DecimalArray;
 use vortex_array::arrays::PrimitiveArray;
 use vortex_array::arrays::VarBinViewArray;
 use vortex_array::arrays::bool::BoolArrayExt;
+use vortex_array::arrays::decimal::DecimalArrayExt;
 use vortex_array::builtins::ArrayBuiltins;
 use vortex_array::dtype::DType;
 use vortex_array::dtype::Nullability;

fuzz/src/array/mask.rs

@@ -16,6 +16,7 @@ use vortex_array::arrays::PrimitiveArray;
 use vortex_array::arrays::StructArray;
 use vortex_array::arrays::VarBinViewArray;
 use vortex_array::arrays::bool::BoolArrayExt;
+use vortex_array::arrays::decimal::DecimalArrayExt;
 use vortex_array::arrays::extension::ExtensionArrayExt;
 use vortex_array::arrays::fixed_size_list::FixedSizeListArrayExt;
 use vortex_array::arrays::listview::ListViewArrayExt;

fuzz/src/array/scalar_at.rs

@@ -7,6 +7,7 @@ use vortex_array::Canonical;
 use vortex_array::ExecutionCtx;
 use vortex_array::IntoArray;
 use vortex_array::arrays::bool::BoolArrayExt;
+use vortex_array::arrays::decimal::DecimalArrayExt;
 use vortex_array::arrays::extension::ExtensionArrayExt;
 use vortex_array::arrays::fixed_size_list::FixedSizeListArrayExt;
 use vortex_array::arrays::listview::ListViewArrayExt;

vortex-array/src/aggregate_fn/fns/min_max/decimal.rs

@@ -9,6 +9,7 @@ use super::MinMaxPartial;
 use super::MinMaxResult;
 use crate::ExecutionCtx;
 use crate::arrays::DecimalArray;
+use crate::arrays::decimal::DecimalArrayExt;
 use crate::dtype::DecimalDType;
 use crate::dtype::NativeDecimalType;
 use crate::dtype::Nullability::NonNullable;

vortex-array/src/aggregate_fn/fns/sum/mod.rs

@@ -300,9 +300,9 @@ impl AggregateFnVTable for Sum {
 
         let result = match batch {
             Columnar::Canonical(c) => match c {
-                Canonical::Primitive(p) => accumulate_primitive(&mut inner, p, ctx, skip_nans),
+                Canonical::Primitive(a) => accumulate_primitive(&mut inner, a, ctx, skip_nans),
+                Canonical::Decimal(a) => accumulate_decimal(&mut inner, a, ctx),
                 Canonical::Bool(b) => accumulate_bool(&mut inner, b, ctx),
-                Canonical::Decimal(d) => accumulate_decimal(&mut inner, d, ctx),
                 _ => vortex_bail!("Unsupported canonical type for sum: {}", batch.dtype()),
             },
             Columnar::Constant(_) => unreachable!(),

vortex-array/src/array/erased.rs

@@ -804,3 +804,30 @@ impl<V: VTable> Matcher for V {
         Some(unsafe { ArrayView::new_unchecked(array, &inner.data) })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use vortex_buffer::buffer;
+
+    use super::*;
+    use crate::arrays::Decimal;
+    use crate::arrays::DecimalArray;
+    use crate::arrays::Primitive;
+    use crate::dtype::DecimalDType;
+
+    #[test]
+    fn fixed_width_arrays_match_their_logical_vtable() {
+        let primitive = buffer![1i32].into_array();
+        let decimal = DecimalArray::new(
+            buffer![1i32],
+            DecimalDType::new(1, 0),
+            Validity::NonNullable,
+        )
+        .into_array();
+
+        assert!(primitive.is::<Primitive>());
+        assert!(!primitive.is::<Decimal>());
+        assert!(decimal.is::<Decimal>());
+        assert!(!decimal.is::<Primitive>());
+    }
+}