Struct mz_persist::indexed::encoding::BlobTraceBatchPart

pub struct BlobTraceBatchPart<T> {
    pub desc: Description<T>,
    pub index: u64,
    pub updates: Vec<ColumnarRecords>,
}

The structure serialized and stored as a value in crate::location::Blob storage for data keys corresponding to trace data.

This batch represents the data that was originally written at some time in [lower, upper) (more precisely !< lower and < upper). The individual record times may have later been advanced by compaction to something <= since. This means the ability to reconstruct the state of the collection at times < since has been lost. However, there may still be records present in the batch whose times are < since. Users iterating through updates must take care to advance records with times < since to since in order to correctly answer queries at times >= since.

Invariants:

• The [lower, upper) interval of times in desc is non-empty.
• The timestamp of each update is >= to desc.lower().
• The timestamp of each update is < desc.upper() iff desc.upper() > desc.since(). Otherwise the timestamp of each update is <= desc.since().
• The values in updates are sorted by (key, value, time).
• The values in updates are “consolidated”, i.e. (key, value, time) is unique.
• All entries have a non-zero diff.

TODO: disallow empty trace batch parts in the future so there is one unique way to represent an empty trace batch.

Fields

desc: Description<T>

Which updates are included in this batch.

There may be other parts for the batch that also contain updates within the specified [lower, upper) range.

index: u64

Index of this part in the list of parts that form the batch.

updates: Vec<ColumnarRecords>

The updates themselves.

Implementations

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

pub fn validate(&self) -> Result<(), Error>

Asserts the documented invariants, returning an error if any are violated.

pub fn encode<B>(&self, buf: &mut B)

where B: BufMut,

Encodes an BlobTraceBatchPart into the Parquet format.

pub fn decode( buf: &SegmentedBytes, metrics: &ColumnarMetrics ) -> Result<Self, Error>

Decodes a BlobTraceBatchPart from the Parquet format.

pub fn key_lower(&self) -> &[u8]

Scans the part and returns a lower bound on the contained keys.

Trait Implementations

impl<T: Clone> Clone for BlobTraceBatchPart<T>

fn clone(&self) -> BlobTraceBatchPart<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for BlobTraceBatchPart<T>

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

Formats the value using the given formatter.