Struct SimpleStringAggAccumulator 

pub(crate) struct SimpleStringAggAccumulator {
    delimiter: String,
    accumulated_string: String,
    has_value: bool,
}

StringAgg accumulator for the simple case (no order or distinct specified) This accumulator is more efficient than StringAggAccumulator because it accumulates the string directly, whereas StringAggAccumulator uses ArrayAggAccumulator.

Fields

delimiter: String

accumulated_string: String

Updated during update_batch(). e.g. “foo,bar”

has_value: bool

Implementations

impl SimpleStringAggAccumulator

pub fn new(delimiter: &str) -> Self

fn append_strings<'a, I>(&mut self, iter: I)

where I: Iterator<Item = Option<&'a str>>,

Trait Implementations

impl Accumulator for SimpleStringAggAccumulator

fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()>

Updates the accumulator’s state from its input.

fn evaluate(&mut self) -> Result<ScalarValue>

Returns the final aggregate value, consuming the internal state.

fn size(&self) -> usize

Returns the allocated size required for this accumulator, in bytes, including Self.

fn state(&mut self) -> Result<Vec<ScalarValue>>

Returns the intermediate state of the accumulator, consuming the intermediate state.

fn merge_batch(&mut self, values: &[ArrayRef]) -> Result<()>

Updates the accumulator’s state from an Array containing one or more intermediate values.

fn retract_batch( &mut self, _values: &[Arc<dyn Array>], ) -> Result<(), DataFusionError>

Retracts (removed) an update (caused by the given inputs) to accumulator’s state.

fn supports_retract_batch(&self) -> bool

Does the accumulator support incrementally updating its value by removing values.

impl Debug for SimpleStringAggAccumulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.