Trait HashKey

pub trait HashKey:
    EstimateSize
    + Clone
    + Debug
    + Hash
    + Eq
    + Sized
    + Send
    + Sync
    + 'static {
    type Bitmap: NullBitmap;

    // Required methods
    fn build_many(column_indices: &[usize], data_chunk: &DataChunk) -> Vec<Self>;
    fn deserialize(&self, data_types: &[DataType]) -> ArrayResult<OwnedRow>;
    fn deserialize_to_builders(
        &self,
        array_builders: &mut [ArrayBuilderImpl],
        data_types: &[DataType],
    ) -> ArrayResult<()>;
    fn null_bitmap(&self) -> &Self::Bitmap;
}

Trait for different kinds of hash keys.

Current comparison implementation treats null == null. This is consistent with postgresql’s group by implementation, but not join. In pg’s join implementation, null != null, and the join executor should take care of this.

Required Associated Types

type Bitmap: NullBitmap

Required Methods

fn build_many(column_indices: &[usize], data_chunk: &DataChunk) -> Vec<Self>

Build hash keys from the given data_chunk with column_indices in a batch.

fn deserialize(&self, data_types: &[DataType]) -> ArrayResult<OwnedRow>

Deserializes the hash key into a row.

fn deserialize_to_builders( &self, array_builders: &mut [ArrayBuilderImpl], data_types: &[DataType], ) -> ArrayResult<()>

Deserializes the hash key into array builders.

fn null_bitmap(&self) -> &Self::Bitmap

Get the null bitmap of the hash key.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<S: KeyStorage, N: NullBitmap> HashKey for HashKeyImpl<S, N>

type Bitmap = N