Struct parquet::file::writer::SerializedRowGroupWriter

pub struct SerializedRowGroupWriter<'a, W: Write> { /* private fields */ }

Parquet row group writer API. Provides methods to access column writers in an iterator-like fashion, order is guaranteed to match the order of schema leaves (column descriptors).

All columns should be written sequentially; the main workflow is:

• Request the next column using next_column method - this will return None if no more columns are available to write.
• Once done writing a column, close column writer with close
• Once all columns have been written, close row group writer with close method - it will return row group metadata and is no-op on already closed row group.

Implementations

impl<'a, W: Write + Send> SerializedRowGroupWriter<'a, W>

pub fn new( schema_descr: SchemaDescPtr, properties: WriterPropertiesPtr, buf: &'a mut TrackedWrite<W>, row_group_index: i16, on_close: Option<OnCloseRowGroup<'a>> ) -> Self

Creates a new SerializedRowGroupWriter with:

• schema_descr - the schema to write
• properties - writer properties
• buf - the buffer to write data to
• row_group_index - row group index in this parquet file.
• file_offset - file offset of this row group in this parquet file.
• on_close - an optional callback that will invoked on Self::close

pub fn next_column(&mut self) -> Result<Option<SerializedColumnWriter<'_>>>

Returns the next column writer, if available; otherwise returns None. In case of any IO error or Thrift error, or if row group writer has already been closed returns Err.

pub fn append_column<R: ChunkReader>( &mut self, reader: &R, close: ColumnCloseResult ) -> Result<()>

Append an encoded column chunk from another source without decoding it

This can be used for efficiently concatenating or projecting parquet data, or encoding parquet data to temporary in-memory buffers

See Self::next_column for writing data that isn’t already encoded

pub fn close(self) -> Result<RowGroupMetaDataPtr>

Closes this row group writer and returns row group metadata.