Enum VirtualValue 

#[non_exhaustive]
pub enum VirtualValue {
    Materialized {
        value: Value,
        schema: Schema,
    },
    Cached {
        key: CacheKey,
        schema: Schema,
    },
    Deferred {
        producer_node_id: String,
        cache_key: CacheKey,
        schema: Schema,
    },
    Stream {
        source_id: String,
        schema: Schema,
    },
}

A lazy reference to a value that can be materialized on demand.

This is the core of Soma’s data virtualization. Instead of computing and storing every intermediate result, values are represented as references that carry enough information to:

• Inspect schema without loading data
• Check whether the data is already available
• Compute it when needed

Like Denodo’s data virtualization, but for computation rather than SQL.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Materialized

Already computed and in memory. Ready to use.

Fields

value: Value

schema: Schema

Cached

Stored in cache (K/V store). Can be loaded on demand.

Fields

key: CacheKey

schema: Schema

Deferred

Not computed yet. Carries the “recipe” to produce it: which node produces it, and what its cache key would be.

Fields

producer_node_id: String

cache_key: CacheKey

schema: Schema

Stream

A stream that materializes chunk by chunk.

Fields

source_id: String

schema: Schema

Implementations

impl VirtualValue

pub fn materialized(value: Value) -> Self

Create a materialized value with auto-inferred schema.

pub fn materialized_with_schema(value: Value, schema: Schema) -> Self

Create a materialized value with explicit schema.

pub fn cached(key: CacheKey, schema: Schema) -> Self

Create a cached reference.

pub fn deferred( producer_node_id: impl Into<String>, cache_key: CacheKey, schema: Schema, ) -> Self

Create a deferred (not yet computed) reference.

pub fn schema(&self) -> &Schema

Get the schema without materializing the value.

pub fn status(&self) -> ValueStatus

Get the current status.

pub fn as_value(&self) -> Option<&Value>

Get the materialized value if already in memory.

pub fn cache_key(&self) -> Option<&CacheKey>

Get the cache key (if this value is cached or deferred).

pub fn try_load(&self, cache: &dyn CacheStore) -> Result<Option<Value>>

Materialize from a cache store. Returns the value if found, None if not cached.

pub fn resolve(&self, cache: &dyn CacheStore) -> Result<Self>

Upgrade this reference: if Deferred, check cache; if Cached, load. Returns a new VirtualValue that may be closer to Materialized.

Trait Implementations

impl Clone for VirtualValue

fn clone(&self) -> VirtualValue

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VirtualValue

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for VirtualValue

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for VirtualValue

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

Formats the value using the given formatter.

impl From<Value> for VirtualValue

fn from(value: Value) -> Self

Converts to this type from the input type.

impl Serialize for VirtualValue

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

where __S: Serializer,

Serialize this value into the given Serde serializer.