Function polars::export::arrow::io::parquet::read::read_columns_async

pub async fn read_columns_async<'b, R, F>(
    factory: F, 
    columns: &'a [ColumnChunkMetaData], 
    field_name: &'_ str
) -> Result<Vec<(&'a ColumnChunkMetaData, Vec<u8, Global>), Global>, ArrowError> where
    R: AsyncRead + AsyncSeek + Send + Unpin,
    F: Fn() -> Pin<Box<dyn Future<Output = Result<R, Error>> + Send + 'b, Global>> + Clone, 

This is supported on crate feature io_parquet only.

Reads all columns that are part of the parquet field field_name

Implementation

This operation is IO-bounded O(C) where C is the number of columns associated to the field (one for non-nested types)

It does so asynchronously via a single join_all over all the necessary columns for field_name.