Struct persist::indexed::encoding::BlobTraceBatch

pub struct BlobTraceBatch {
    pub desc: Description<u64>,
    pub updates: Vec<ColumnarRecords>,
}

The structure serialized and stored as a value in crate::storage::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.
• (Intentionally no invariant around update non-emptiness because we might need empty batches to make the timestamps line up.)

TODO: This probably wants to be a different level of abstraction, so we can put multiple small batches in a single blob but also break a very large batch over multiple blobs. We also may want to break the latter into chunks for checksum and encryption?

Fields

desc: Description<u64>

Which updates are included in this batch.

updates: Vec<ColumnarRecords>

The updates themselves.

Implementations

impl BlobTraceBatch

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

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

Trait Implementations

impl Clone for BlobTraceBatch

fn clone(&self) -> BlobTraceBatch

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Codec for BlobTraceBatch

fn codec_name() -> String

Name of the codec.

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

Encode a key or value for permanent storage.

fn decode<'a>(buf: &'a [u8]) -> Result<Self, String>

Decode a key or value previous encoded with this codec’s Codec::encode.

impl Debug for BlobTraceBatch

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

Formats the value using the given formatter.