Struct DataRowCursor 

pub struct DataRowCursor { /* private fields */ }

Available on crate feature sea-ql only.

A cursor that emits dynamically-typed DataRows decoded from RowBinaryWithNamesAndTypes.

Obtain one via crate::query::Query::fetch_rows.

Implementations

impl DataRowCursor

pub fn columns(&self) -> Option<&[Arc<str>]>

Returns column names after the header has been read (i.e., after the first next call returns).

pub fn received_bytes(&self) -> u64

Returns the total size in bytes received from the CH server since the cursor was created.

This counts only the payload size (no HTTP headers).

pub fn decoded_bytes(&self) -> u64

Returns the total size in bytes decompressed since the cursor was created.

pub async fn next(&mut self) -> Result<Option<DataRow>>

Emits the next row.

Returns Ok(None) when all rows have been consumed. The result is unspecified if called after an Err is returned.

Cancel safety

This method is cancellation safe.

pub async fn next_batch(&mut self, max_rows: usize) -> Result<Option<RowBatch>>

Reads up to max_rows rows and returns them as a column-oriented RowBatch.

Returns Ok(None) when all rows have been consumed. The result is unspecified if called after an Err is returned.

pub async fn next_arrow_batch( &mut self, max_rows: usize, ) -> Result<Option<RecordBatch>>

Available on crate feature arrow only.

Reads up to max_rows rows and returns them as an Arrow RecordBatch.

The schema is derived from the RowBinaryWithNamesAndTypes header using crate::arrow::schema::from_columns and is available on the returned batch via [RecordBatch::schema].

Returns Ok(None) when all rows have been consumed. The result is unspecified if called after an Err is returned.