Enum WriterTransform 

pub enum WriterTransform {
    Raw,
    BitPacked,
    BooleanRle,
    FrameOfReference,
    Delta,
    DeltaOfDelta,
    ByteStreamSplit,
    Constant,
    Dictionary,
    RunLength,
}

A value transform/layout that a writer can apply without profiling.

Some variants describe a complete column layout rather than one physical stream transform. For example, Dictionary uses raw dictionary values and bit-packed indices. Those supporting streams retain the transforms required by the v0.2 layout; the selected variant is the fixed policy for the dense column values.

Not every variant applies to every logical type, and WriterEncoding::Fixed documents which set a column offers.

Variants

Raw

Store canonical values without transforming them.

BitPacked

Store unsigned values in a bit-packed stream.

BooleanRle

Store boolean values as value/run pairs.

FrameOfReference

Store a minimum followed by packed differences.

Delta

Store the first value followed by packed deltas.

DeltaOfDelta

Store the first value, first delta, and packed delta differences.

ByteStreamSplit

Transpose fixed-width values by byte position.

Constant

Store one value and refer to it for every row.

Dictionary

Store distinct values once and pack row indices.

RunLength

Store one value and run length for each contiguous run.

Trait Implementations

impl Clone for WriterTransform

fn clone(&self) -> WriterTransform

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for WriterTransform

impl Debug for WriterTransform

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

Formats the value using the given formatter.

impl Eq for WriterTransform

impl PartialEq for WriterTransform

fn eq(&self, other: &WriterTransform) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for WriterTransform