Struct TableStrategy 

pub struct TableStrategy { /* private fields */ }

A configurable strategy for writing tables with nested field columns, allowing overrides for specific leaf columns.

Implementations

impl TableStrategy

pub fn new( validity: Arc<dyn LayoutStrategy>, fallback: Arc<dyn LayoutStrategy>, ) -> Self

Create a new writer with the specified write strategies for validity, and for all leaf fields, with no overrides.

Additional overrides can be configured using the with_leaf_strategy method.

Example

// Build a write strategy that does not compress validity or any leaf fields.
let flat = Arc::new(FlatLayoutStrategy::default());

let strategy = TableStrategy::new(flat.clone(), flat.clone());

pub fn with_field_writer( self, field_path: impl Into<FieldPath>, writer: Arc<dyn LayoutStrategy>, ) -> Self

Add a custom write strategy for the given leaf field.

Example

// A strategy for compressing data using the balanced BtrBlocks compressor.
let compress = CompressingStrategy::new_btrblocks(FlatLayoutStrategy::default(), true);

// Our combined strategy uses no compression for validity buffers, BtrBlocks compression
// for most columns, and stores a nested binary column uncompressed (flat) because it
// is pre-compressed or never filtered on.
let strategy = TableStrategy::new(
        Arc::new(FlatLayoutStrategy::default()),
        Arc::new(compress),
    )
    .with_field_writer(
        field_path!(request.body.bytes),
        Arc::new(FlatLayoutStrategy::default()),
    );

pub fn with_field_writers( self, writers: impl IntoIterator<Item = (FieldPath, Arc<dyn LayoutStrategy>)>, ) -> Self

Set writers for several fields at once.

See also: with_field_writer.

pub fn with_default_strategy(self, default: Arc<dyn LayoutStrategy>) -> Self

Override the default strategy for leaf columns that don’t have overrides.

pub fn with_validity_strategy(self, validity: Arc<dyn LayoutStrategy>) -> Self

Override the strategy for compressing struct validity at all levels of the schema tree.

Trait Implementations

impl LayoutStrategy for TableStrategy

Specialized strategy for when we exactly know the input schema.

fn write_stream<'life0, 'async_trait>( &'life0 self, ctx: ArrayContext, segment_sink: SegmentSinkRef, stream: SendableSequentialStream, eof: SequencePointer, handle: Handle, ) -> Pin<Box<dyn Future<Output = VortexResult<LayoutRef>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Asynchronously process an ordered stream of array chunks, emitting them into a sink and returning the Layout instance that can be parsed to retrieve the data from rest.

fn buffered_bytes(&self) -> u64

Returns the number of bytes currently buffered by this strategy and any child strategies.