Struct Writer 

pub struct Writer { /* private fields */ }

A writer for the Lance v2.2 file grammar.

The concrete writer owns the v2.2 encoding composition, finish ordering, and exact footer identity. Shared components only execute the structural encoding and I/O mechanisms selected here.

Implementations

impl Writer

pub fn try_new( object_writer: Box<dyn ObjectWriter>, schema: Schema, options: FileWriterOptions, ) -> Result<Self>

Create a v2.2 writer with an explicit schema.

pub fn try_new_with_compression( object_writer: Box<dyn ObjectWriter>, schema: Schema, options: FileWriterOptions, compression: CompressionParams, ) -> Result<Self>

Create a v2.2 writer with explicit compression tuning.

pub fn new_lazy( object_writer: Box<dyn ObjectWriter>, options: FileWriterOptions, ) -> Self

Create a v2.2 writer whose schema is inferred from the first batch.

pub fn new_lazy_with_compression( object_writer: Box<dyn ObjectWriter>, options: FileWriterOptions, compression: CompressionParams, ) -> Self

Create a lazy v2.2 writer with explicit compression tuning.

pub fn with_page_metadata_spill( self, object_store: Arc<ObjectStore>, path: Path, ) -> Self

Spill page metadata to a sidecar file instead of retaining it in memory.

pub async fn write_batches( &mut self, batches: impl Iterator<Item = &RecordBatch>, ) -> Result<()>

Schedule batches to be written in iteration order.

pub async fn write_batch(&mut self, batch: &RecordBatch) -> Result<()>

Schedule one record batch for writing.

pub async fn write_column( &mut self, column_index: usize, array: ArrayRef, ) -> Result<()>

Write one top-level field, advancing only that field’s row count.

pub async fn write_external_buffer( &mut self, bytes: &[u8], ) -> Result<(u64, u64)>

Append a buffer whose page or column metadata is supplied externally.

pub fn add_schema_metadata( &mut self, key: impl Into<String>, value: impl Into<String>, )

Add an entry to the schema metadata written in the file descriptor.

pub fn initialize_with_external_metadata( &mut self, schema: Schema, column_metadata: Vec<ColumnMetadata>, rows_written: u64, )

Prepare the writer for encoded column data produced externally.

pub async fn add_global_buffer(&mut self, buffer: Bytes) -> Result<u32>

Add an arbitrary global buffer and return its one-based index.

pub async fn finish(&mut self) -> Result<FileWriteSummary>

Finish the v2.2 file and close its object writer.

pub async fn abort(&mut self)

Abandon this write.

pub async fn tell(&mut self) -> Result<u64>

Return the current object-writer position.

pub fn field_id_to_column_indices(&self) -> &[(u32, u32)]

Return the field-id to physical-column mapping selected by v2.2.