Dandandan commented on code in PR #15324:
URL: https://github.com/apache/datafusion/pull/15324#discussion_r2011540550
##########
datafusion/functions-aggregate/src/count.rs:
##########
@@ -227,137 +226,37 @@ impl AggregateUDFImpl for Count {
return not_impl_err!("COUNT DISTINCT with multiple arguments");
}
- let data_type = &acc_args.exprs[0].data_type(acc_args.schema)?;
- Ok(match data_type {
- // try and use a specialized accumulator if possible, otherwise
fall back to generic accumulator
- DataType::Int8 => Box::new(
- PrimitiveDistinctCountAccumulator::<Int8Type>::new(data_type),
- ),
- DataType::Int16 => Box::new(
- PrimitiveDistinctCountAccumulator::<Int16Type>::new(data_type),
- ),
- DataType::Int32 => Box::new(
- PrimitiveDistinctCountAccumulator::<Int32Type>::new(data_type),
- ),
- DataType::Int64 => Box::new(
- PrimitiveDistinctCountAccumulator::<Int64Type>::new(data_type),
- ),
- DataType::UInt8 => Box::new(
- PrimitiveDistinctCountAccumulator::<UInt8Type>::new(data_type),
- ),
- DataType::UInt16 => Box::new(
-
PrimitiveDistinctCountAccumulator::<UInt16Type>::new(data_type),
- ),
- DataType::UInt32 => Box::new(
-
PrimitiveDistinctCountAccumulator::<UInt32Type>::new(data_type),
- ),
- DataType::UInt64 => Box::new(
-
PrimitiveDistinctCountAccumulator::<UInt64Type>::new(data_type),
- ),
- DataType::Decimal128(_, _) =>
Box::new(PrimitiveDistinctCountAccumulator::<
- Decimal128Type,
- >::new(data_type)),
- DataType::Decimal256(_, _) =>
Box::new(PrimitiveDistinctCountAccumulator::<
- Decimal256Type,
- >::new(data_type)),
-
- DataType::Date32 => Box::new(
-
PrimitiveDistinctCountAccumulator::<Date32Type>::new(data_type),
- ),
- DataType::Date64 => Box::new(
-
PrimitiveDistinctCountAccumulator::<Date64Type>::new(data_type),
- ),
- DataType::Time32(TimeUnit::Millisecond) => Box::new(
-
PrimitiveDistinctCountAccumulator::<Time32MillisecondType>::new(
- data_type,
- ),
- ),
- DataType::Time32(TimeUnit::Second) => Box::new(
-
PrimitiveDistinctCountAccumulator::<Time32SecondType>::new(data_type),
- ),
- DataType::Time64(TimeUnit::Microsecond) => Box::new(
-
PrimitiveDistinctCountAccumulator::<Time64MicrosecondType>::new(
- data_type,
- ),
- ),
- DataType::Time64(TimeUnit::Nanosecond) => Box::new(
-
PrimitiveDistinctCountAccumulator::<Time64NanosecondType>::new(data_type),
- ),
- DataType::Timestamp(TimeUnit::Microsecond, _) => Box::new(
-
PrimitiveDistinctCountAccumulator::<TimestampMicrosecondType>::new(
- data_type,
- ),
- ),
- DataType::Timestamp(TimeUnit::Millisecond, _) => Box::new(
-
PrimitiveDistinctCountAccumulator::<TimestampMillisecondType>::new(
- data_type,
- ),
- ),
- DataType::Timestamp(TimeUnit::Nanosecond, _) => Box::new(
-
PrimitiveDistinctCountAccumulator::<TimestampNanosecondType>::new(
- data_type,
- ),
- ),
- DataType::Timestamp(TimeUnit::Second, _) => Box::new(
-
PrimitiveDistinctCountAccumulator::<TimestampSecondType>::new(data_type),
- ),
-
- DataType::Float16 => {
- Box::new(FloatDistinctCountAccumulator::<Float16Type>::new())
- }
- DataType::Float32 => {
- Box::new(FloatDistinctCountAccumulator::<Float32Type>::new())
- }
- DataType::Float64 => {
- Box::new(FloatDistinctCountAccumulator::<Float64Type>::new())
- }
-
- DataType::Utf8 => {
-
Box::new(BytesDistinctCountAccumulator::<i32>::new(OutputType::Utf8))
- }
- DataType::Utf8View => {
-
Box::new(BytesViewDistinctCountAccumulator::new(OutputType::Utf8View))
- }
- DataType::LargeUtf8 => {
-
Box::new(BytesDistinctCountAccumulator::<i64>::new(OutputType::Utf8))
- }
- DataType::Binary =>
Box::new(BytesDistinctCountAccumulator::<i32>::new(
- OutputType::Binary,
- )),
- DataType::BinaryView =>
Box::new(BytesViewDistinctCountAccumulator::new(
- OutputType::BinaryView,
- )),
- DataType::LargeBinary =>
Box::new(BytesDistinctCountAccumulator::<i64>::new(
- OutputType::Binary,
- )),
-
- // Use the generic accumulator based on `ScalarValue` for all
other types
- _ => Box::new(DistinctCountAccumulator {
- values: HashSet::default(),
- state_data_type: data_type.clone(),
- }),
- })
+ Ok(Box::new(DistinctCountAccumulator {
+ values: HashSet::default(),
+ random_state: RandomState::with_seeds(1, 2, 3, 4),
Review Comment:
Hm... I think we can't store *only* the hashes as it won't account for hash
collisions (two values mapping to the same value). There is not a seed that
prevents that (as the number of possible values in e.g. a `u64` is much smaller
than e.g. a string with 20 bytes)
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