Struct BlobTraceBatchPartReader 

pub struct BlobTraceBatchPartReader<T> { /* private fields */ }

Incremental decoder over a parquet-encoded BlobTraceBatchPart.

Decodes at most batch_rows rows per call to Self::next_updates, so only the encoded bytes and one decoded batch are resident at a time. Each batch is validated like BlobTraceBatchPart::validate validates a whole part.

Successive batches cover the part’s rows in their encoded order, without gaps or overlap. A caller that consolidates adjacent updates can therefore carry its pending update across a batch boundary and merge the same updates as it would on the whole part.

Implementations

impl<T: Timestamp + Codec64> BlobTraceBatchPartReader<T>

pub fn new(buf: SegmentedBytes, batch_rows: usize) -> Result<Self, Error>

Opens buf for decoding in batches of at most batch_rows rows.

A batch_rows of 0 is treated as 1.

pub fn desc(&self) -> &Description<T>

The part’s inline description.

pub fn num_rows(&self) -> usize

The total number of rows in the part, decoded or not.

pub fn next_updates( &mut self, metrics: &ColumnarMetrics, ) -> Option<Result<BlobTraceUpdates, Error>>

Decodes the next batch of rows, or returns None once all rows have been returned.

Trait Implementations

impl<T: Debug> Debug for BlobTraceBatchPartReader<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.