Enum EmbeddingRole 

pub enum EmbeddingRole {
    Query,
    Passage,
    Generic,
}

Stable: role of text in asymmetric retrieval.

Models trained with asymmetric objectives (E5, Qwen3-Embedding) use different prompt prefixes for queries vs documents. Providing the wrong role causes the embedding to land in the wrong region of the model’s retrieval space, degrading retrieval quality.

Use EmbeddingService::embed_query / EmbeddingService::embed_passage to apply the correct prefix automatically. The role is also included in the cache key so that embed_query("hello") and embed_passage("hello") are stored as separate entries even when the raw text is identical.

Variants

Query

Query / question text — may receive a query-side prompt prefix.

Passage

Document / passage text — may receive a passage-side prompt prefix.

Generic

Generic text with no role-specific prefix (backwards-compatible default).

Trait Implementations

impl Clone for EmbeddingRole

fn clone(&self) -> EmbeddingRole

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EmbeddingRole

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

Formats the value using the given formatter.

impl Hash for EmbeddingRole

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for EmbeddingRole

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for EmbeddingRole

impl Eq for EmbeddingRole

impl StructuralPartialEq for EmbeddingRole