Trait parquet::file::reader::RowGroupReader [−][src]
pub trait RowGroupReader {
fn metadata(&self) -> &RowGroupMetaData;
fn num_columns(&self) -> usize;
fn get_column_page_reader(&self, i: usize) -> Result<Box<dyn PageReader>>;
fn get_row_iter(
&self,
projection: Option<SchemaType>
) -> Result<RowIter<'_>>;
fn get_column_reader(&self, i: usize) -> Result<ColumnReader> { ... }
}
Expand description
Parquet row group reader API. With this, user can get metadata information about the row group, as well as readers for each individual column chunk.
Required methods
fn metadata(&self) -> &RowGroupMetaData
fn metadata(&self) -> &RowGroupMetaData
Get metadata information about this row group.
fn num_columns(&self) -> usize
fn num_columns(&self) -> usize
Get the total number of column chunks in this row group.
fn get_column_page_reader(&self, i: usize) -> Result<Box<dyn PageReader>>
fn get_column_page_reader(&self, i: usize) -> Result<Box<dyn PageReader>>
Get page reader for the i
th column chunk.
fn get_row_iter(&self, projection: Option<SchemaType>) -> Result<RowIter<'_>>
fn get_row_iter(&self, projection: Option<SchemaType>) -> Result<RowIter<'_>>
Get iterator of Row
s from this row group.
Projected schema can be a subset of or equal to the file schema, when it is None, full file schema is assumed.
Provided methods
fn get_column_reader(&self, i: usize) -> Result<ColumnReader>
fn get_column_reader(&self, i: usize) -> Result<ColumnReader>
Get value reader for the i
th column chunk.