Struct GroupValuesBytes 

pub struct GroupValuesBytes<O: OffsetSizeTrait> {
    map: ArrowBytesMap<O, usize>,
    num_groups: usize,
}

A GroupValues storing single column of Utf8/LargeUtf8/Binary/LargeBinary values

This specialization is significantly faster than using the more general purpose Rows format

Fields

map: ArrowBytesMap<O, usize>

Map string/binary values to group index

num_groups: usize

The total number of groups so far (used to assign group_index)

Implementations

impl<O: OffsetSizeTrait> GroupValuesBytes<O>

pub fn new(output_type: OutputType) -> Self

Trait Implementations

impl<O: OffsetSizeTrait> GroupValues for GroupValuesBytes<O>

fn intern(&mut self, cols: &[ArrayRef], groups: &mut Vec<usize>) -> Result<()>

Calculates the group id for each input row of cols, assigning new group ids as necessary.

fn size(&self) -> usize

Returns the number of bytes of memory used by this GroupValues

fn is_empty(&self) -> bool

Returns true if this GroupValues is empty

fn len(&self) -> usize

The number of values (distinct group values) stored in this GroupValues

fn emit(&mut self, emit_to: EmitTo) -> Result<Vec<ArrayRef>>

Emits the group values

fn clear_shrink(&mut self, _batch: &RecordBatch)

Clear the contents and shrink the capacity to the size of the batch (free up memory usage)