Struct VersionedReadEntry 

pub struct VersionedReadEntry {
    pub engine: EngineTag,
    pub collection: String,
    pub key: ReadKeyIdent,
    pub read_version: WriteVersion,
    pub home_vshard: Option<u32>,
}

One versioned, predicate-aware read observed by a transaction, carried on the replicated Calvin TxClass so participants can validate it at the commit serialization point.

read_version is a data-group log position, so any replica of the read’s vShard validates it. The enclosing TxClass scopes the tenant; per-database scoping is carried by the transaction as a whole.

Fields

engine: EngineTag

Which engine served the read.

collection: String

The collection the read observed.

key: ReadKeyIdent

Point-key or collection-scoped-predicate identity of the observation.

read_version: WriteVersion

The version of what the read observed on its home vShard.

home_vshard: Option<u32>

The vShard whose write versions validate this read. None homes the read to its collection’s vShard. A graph read names the key vShard it read edges on, because edges live on their endpoints’ vShards. A homed read with an empty collection observed every collection there, so it validates against the vShard’s latest version.

Trait Implementations

impl Clone for VersionedReadEntry

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VersionedReadEntry

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for VersionedReadEntry

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for VersionedReadEntry

impl<'__msgpack_de> FromMessagePack<'__msgpack_de> for VersionedReadEntry

fn read<R: Read<'__msgpack_de>>(reader: &mut R) -> Result<Self, Error>

where Self: Sized,

Reads the MessagePack representation of this value from the provided reader.

impl PartialEq for VersionedReadEntry

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for VersionedReadEntry

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for VersionedReadEntry

impl ToMessagePack for VersionedReadEntry

fn write<W: Write>(&self, writer: &mut W) -> Result<(), Error>

Writes the MessagePack representation of this value into the provided writer.

fn size_hint(&self) -> Option<TrustedSizeHint>

Returns a trusted upper bound for the number of bytes written by the next call to Self::write, or None when it cannot be determined cheaply.

fn max_size() -> Option<TrustedSizeHint>

Returns a trusted upper bound valid for every value of this type.

fn write_slice<W>(values: &[Self], writer: &mut W) -> Result<(), Error>

where W: Write, Self: Sized,

Writes the MessagePack representation of a slice of values into the provided writer.