Trait parquet::arrow::arrow_reader::ArrowReader
source · [−]pub trait ArrowReader {
type RecordReader: RecordBatchReader;
fn get_schema(&mut self) -> Result<Schema>;
fn get_schema_by_columns(&mut self, mask: ProjectionMask) -> Result<Schema>;
fn get_record_reader(
&mut self,
batch_size: usize
) -> Result<Self::RecordReader>;
fn get_record_reader_by_columns(
&mut self,
mask: ProjectionMask,
batch_size: usize
) -> Result<Self::RecordReader>;
}Use ParquetRecordBatchReaderBuilder instead
Expand description
Arrow reader api. With this api, user can get arrow schema from parquet file, and read parquet data into arrow arrays.
Required Associated Types
Use ParquetRecordBatchReaderBuilder instead
Required Methods
sourcefn get_schema(&mut self) -> Result<Schema>
fn get_schema(&mut self) -> Result<Schema>
Use ParquetRecordBatchReaderBuilder instead
Read parquet schema and convert it into arrow schema.
sourcefn get_schema_by_columns(&mut self, mask: ProjectionMask) -> Result<Schema>
fn get_schema_by_columns(&mut self, mask: ProjectionMask) -> Result<Schema>
Use ParquetRecordBatchReaderBuilder instead
Read parquet schema and convert it into arrow schema.
This schema only includes columns identified by mask.
sourcefn get_record_reader(&mut self, batch_size: usize) -> Result<Self::RecordReader>
fn get_record_reader(&mut self, batch_size: usize) -> Result<Self::RecordReader>
Use ParquetRecordBatchReaderBuilder instead
Returns record batch reader from whole parquet file.
Arguments
batch_size: The size of each record batch returned from this reader. Only the
last batch may contain records less than this size, otherwise record batches
returned from this reader should contains exactly batch_size elements.
sourcefn get_record_reader_by_columns(
&mut self,
mask: ProjectionMask,
batch_size: usize
) -> Result<Self::RecordReader>
fn get_record_reader_by_columns(
&mut self,
mask: ProjectionMask,
batch_size: usize
) -> Result<Self::RecordReader>
Use ParquetRecordBatchReaderBuilder instead
Returns record batch reader whose record batch contains columns identified by
mask.
Arguments
mask: The columns that should be included in record batches.
batch_size: Please refer to get_record_reader.