Merge #4537

4537: Expose distribution shift in settings r=ManyTheFish a=dureuill

See [usage page](https://meilisearch.notion.site/v1-8-AI-search-API-usage-135552d6e85a4a52bc7109be82aeca42#d652adc0890445658aaf36352dbc8802)

# Changes

- Distribution shift added to all embedders.
- Exposed in settings
- Changed the reindexing logic to not trigger a reindex operation when only the distribution shift or API key change

Co-authored-by: Louis Dureuil <louis@meilisearch.com>

index-scheduler/src/snapshots/lib.rs/test_settings_update/after_registering_settings_task.snap

@@ -6,7 +6,7 @@ source: index-scheduler/src/lib.rs
 []
 ----------------------------------------------------------------------
 ### All Tasks:
-0 {uid: 0, status: enqueued, details: { settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> } }, kind: SettingsUpdate { index_uid: "doggos", new_settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> }, is_deletion: false, allow_index_creation: true }}
+0 {uid: 0, status: enqueued, details: { settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet, distribution: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> } }, kind: SettingsUpdate { index_uid: "doggos", new_settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet, distribution: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> }, is_deletion: false, allow_index_creation: true }}
 ----------------------------------------------------------------------
 ### Status:
 enqueued [0,]

index-scheduler/src/snapshots/lib.rs/test_settings_update/settings_update_processed.snap

@@ -6,7 +6,7 @@ source: index-scheduler/src/lib.rs
 []
 ----------------------------------------------------------------------
 ### All Tasks:
-0 {uid: 0, status: succeeded, details: { settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> } }, kind: SettingsUpdate { index_uid: "doggos", new_settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> }, is_deletion: false, allow_index_creation: true }}
+0 {uid: 0, status: succeeded, details: { settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet, distribution: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> } }, kind: SettingsUpdate { index_uid: "doggos", new_settings: Settings { displayed_attributes: NotSet, searchable_attributes: NotSet, filterable_attributes: NotSet, sortable_attributes: NotSet, ranking_rules: NotSet, stop_words: NotSet, non_separator_tokens: NotSet, separator_tokens: NotSet, dictionary: NotSet, synonyms: NotSet, distinct_attribute: NotSet, proximity_precision: NotSet, typo_tolerance: NotSet, faceting: NotSet, pagination: NotSet, embedders: Set({"default": Set(EmbeddingSettings { source: Set(Rest), model: NotSet, revision: NotSet, api_key: Set("My super secret"), dimensions: NotSet, document_template: NotSet, url: Set("http://localhost:7777"), query: NotSet, input_field: NotSet, path_to_embeddings: NotSet, embedding_object: NotSet, input_type: NotSet, distribution: NotSet })}), search_cutoff_ms: NotSet, _kind: PhantomData<meilisearch_types::settings::Unchecked> }, is_deletion: false, allow_index_creation: true }}
 ----------------------------------------------------------------------
 ### Status:
 enqueued []

meilisearch/tests/search/hybrid.rs

@@ -87,6 +87,38 @@ async fn simple_search() {
     snapshot!(response["hits"], @r###"[{"title":"Captain Marvel","desc":"a Shazam ersatz","id":"3","_vectors":{"default":[2.0,3.0]},"_semanticScore":0.99029034},{"title":"Captain Planet","desc":"He's not part of the Marvel Cinematic Universe","id":"2","_vectors":{"default":[1.0,2.0]},"_semanticScore":0.97434163},{"title":"Shazam!","desc":"a Captain Marvel ersatz","id":"1","_vectors":{"default":[1.0,3.0]},"_semanticScore":0.9472136}]"###);
 }
 
+#[actix_rt::test]
+async fn distribution_shift() {
+    let server = Server::new().await;
+    let index = index_with_documents(&server, &SIMPLE_SEARCH_DOCUMENTS).await;
+
+    let search = json!({"q": "Captain", "vector": [1.0, 1.0], "showRankingScore": true, "hybrid": {"semanticRatio": 1.0}});
+    let (response, code) = index.search_post(search.clone()).await;
+    snapshot!(code, @"200 OK");
+    snapshot!(response["hits"], @r###"[{"title":"Captain Marvel","desc":"a Shazam ersatz","id":"3","_vectors":{"default":[2.0,3.0]},"_rankingScore":0.990290343761444,"_semanticScore":0.99029034},{"title":"Captain Planet","desc":"He's not part of the Marvel Cinematic Universe","id":"2","_vectors":{"default":[1.0,2.0]},"_rankingScore":0.974341630935669,"_semanticScore":0.97434163},{"title":"Shazam!","desc":"a Captain Marvel ersatz","id":"1","_vectors":{"default":[1.0,3.0]},"_rankingScore":0.9472135901451112,"_semanticScore":0.9472136}]"###);
+
+    let (response, code) = index
+        .update_settings(json!({
+            "embedders": {
+                "default": {
+                    "distribution": {
+                        "mean": 0.998,
+                        "sigma": 0.01
+                    }
+                }
+            }
+        }))
+        .await;
+
+    snapshot!(code, @"202 Accepted");
+    let response = server.wait_task(response.uid()).await;
+    snapshot!(response["details"], @r###"{"embedders":{"default":{"distribution":{"mean":0.998,"sigma":0.01}}}}"###);
+
+    let (response, code) = index.search_post(search).await;
+    snapshot!(code, @"200 OK");
+    snapshot!(response["hits"], @r###"[{"title":"Captain Marvel","desc":"a Shazam ersatz","id":"3","_vectors":{"default":[2.0,3.0]},"_rankingScore":0.19161224365234375,"_semanticScore":0.19161224},{"title":"Captain Planet","desc":"He's not part of the Marvel Cinematic Universe","id":"2","_vectors":{"default":[1.0,2.0]},"_rankingScore":1.1920928955078125e-7,"_semanticScore":1.1920929e-7},{"title":"Shazam!","desc":"a Captain Marvel ersatz","id":"1","_vectors":{"default":[1.0,3.0]},"_rankingScore":1.1920928955078125e-7,"_semanticScore":1.1920929e-7}]"###);
+}
+
 #[actix_rt::test]
 async fn highlighter() {
     let server = Server::new().await;

milli/src/update/index_documents/mod.rs

@@ -2652,6 +2652,7 @@ mod tests {
                         path_to_embeddings: Setting::NotSet,
                         embedding_object: Setting::NotSet,
                         input_type: Setting::NotSet,
+                        distribution: Setting::NotSet,
                     }),
                 );
                 settings.set_embedder_settings(embedders);

milli/src/update/settings.rs

@@ -976,7 +976,12 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                     match joined {
                         // updated config
                         EitherOrBoth::Both((name, mut old), (_, new)) => {
-                            changed |= old.apply(new);
+                            changed |= EmbeddingSettings::apply_and_need_reindex(&mut old, new);
+                            if changed {
+                                tracing::debug!(embedder = name, "need reindex");
+                            } else {
+                                tracing::debug!(embedder = name, "skip reindex");
+                            }
                             let new = validate_embedding_settings(old, &name)?;
                             new_configs.insert(name, new);
                         }
@@ -1169,6 +1174,7 @@ fn validate_prompt(
             path_to_embeddings,
             embedding_object,
             input_type,
+            distribution,
         }) => {
             // validate
             let template = crate::prompt::Prompt::new(template)
@@ -1188,6 +1194,7 @@ fn validate_prompt(
                 path_to_embeddings,
                 embedding_object,
                 input_type,
+                distribution,
             }))
         }
         new => Ok(new),
@@ -1213,6 +1220,7 @@ pub fn validate_embedding_settings(
         path_to_embeddings,
         embedding_object,
         input_type,
+        distribution,
     } = settings;
 
     if let Some(0) = dimensions.set() {
@@ -1244,6 +1252,7 @@ pub fn validate_embedding_settings(
             path_to_embeddings,
             embedding_object,
             input_type,
+            distribution,
         }));
     };
     match inferred_source {
@@ -1388,6 +1397,7 @@ pub fn validate_embedding_settings(
         path_to_embeddings,
         embedding_object,
         input_type,
+        distribution,
     }))
 }
 

milli/src/vector/hf.rs

@@ -33,6 +33,7 @@ enum WeightSource {
 pub struct EmbedderOptions {
     pub model: String,
     pub revision: Option<String>,
+    pub distribution: Option<DistributionShift>,
 }
 
 impl EmbedderOptions {
@@ -40,6 +41,7 @@ impl EmbedderOptions {
         Self {
             model: "BAAI/bge-base-en-v1.5".to_string(),
             revision: Some("617ca489d9e86b49b8167676d8220688b99db36e".into()),
+            distribution: None,
         }
     }
 }
@@ -193,6 +195,7 @@ impl Embedder {
     }
 
     pub fn distribution(&self) -> Option<DistributionShift> {
+        self.options.distribution.or_else(|| {
             if self.options.model == "BAAI/bge-base-en-v1.5" {
                 Some(DistributionShift {
                     current_mean: ordered_float::OrderedFloat(0.85),
@@ -201,5 +204,6 @@ impl Embedder {
             } else {
                 None
             }
+        })
     }
 }

milli/src/vector/manual.rs

@@ -1,19 +1,21 @@
 use super::error::EmbedError;
-use super::Embeddings;
+use super::{DistributionShift, Embeddings};
 
 #[derive(Debug, Clone, Copy)]
 pub struct Embedder {
     dimensions: usize,
+    distribution: Option<DistributionShift>,
 }
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq, serde::Deserialize, serde::Serialize)]
 pub struct EmbedderOptions {
     pub dimensions: usize,
+    pub distribution: Option<DistributionShift>,
 }
 
 impl Embedder {
     pub fn new(options: EmbedderOptions) -> Self {
-        Self { dimensions: options.dimensions }
+        Self { dimensions: options.dimensions, distribution: options.distribution }
     }
 
     pub fn embed(&self, mut texts: Vec<String>) -> Result<Vec<Embeddings<f32>>, EmbedError> {
@@ -31,4 +33,8 @@ impl Embedder {
     ) -> Result<Vec<Vec<Embeddings<f32>>>, EmbedError> {
         text_chunks.into_iter().map(|prompts| self.embed(prompts)).collect()
     }
+
+    pub fn distribution(&self) -> Option<DistributionShift> {
+        self.distribution
+    }
 }

milli/src/vector/mod.rs

@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 
+use deserr::{DeserializeError, Deserr};
 use ordered_float::OrderedFloat;
 use serde::{Deserialize, Serialize};
 
@@ -292,7 +293,7 @@ impl Embedder {
             Embedder::HuggingFace(embedder) => embedder.distribution(),
             Embedder::OpenAi(embedder) => embedder.distribution(),
             Embedder::Ollama(embedder) => embedder.distribution(),
-            Embedder::UserProvided(_embedder) => None,
+            Embedder::UserProvided(embedder) => embedder.distribution(),
             Embedder::Rest(embedder) => embedder.distribution(),
         }
     }
@@ -317,10 +318,50 @@ pub struct DistributionShift {
     pub current_sigma: OrderedFloat<f32>,
 }
 
-#[derive(Serialize, Deserialize)]
+impl<E> Deserr<E> for DistributionShift
+where
+    E: DeserializeError,
+{
+    fn deserialize_from_value<V: deserr::IntoValue>(
+        value: deserr::Value<V>,
+        location: deserr::ValuePointerRef,
+    ) -> Result<Self, E> {
+        let value = DistributionShiftSerializable::deserialize_from_value(value, location)?;
+        if value.mean < 0. || value.mean > 1. {
+            return Err(deserr::take_cf_content(E::error::<std::convert::Infallible>(
+                None,
+                deserr::ErrorKind::Unexpected {
+                    msg: format!(
+                        "the distribution mean must be in the range [0, 1], got {}",
+                        value.mean
+                    ),
+                },
+                location,
+            )));
+        }
+        if value.sigma <= 0. || value.sigma > 1. {
+            return Err(deserr::take_cf_content(E::error::<std::convert::Infallible>(
+                None,
+                deserr::ErrorKind::Unexpected {
+                    msg: format!(
+                        "the distribution sigma must be in the range ]0, 1], got {}",
+                        value.sigma
+                    ),
+                },
+                location,
+            )));
+        }
+
+        Ok(value.into())
+    }
+}
+
+#[derive(Serialize, Deserialize, Deserr)]
+#[serde(deny_unknown_fields)]
+#[deserr(deny_unknown_fields)]
 struct DistributionShiftSerializable {
-    current_mean: f32,
-    current_sigma: f32,
+    mean: f32,
+    sigma: f32,
 }
 
 impl From<DistributionShift> for DistributionShiftSerializable {
@@ -330,18 +371,13 @@ impl From<DistributionShift> for DistributionShiftSerializable {
             current_sigma: OrderedFloat(current_sigma),
         }: DistributionShift,
     ) -> Self {
-        Self { current_mean, current_sigma }
+        Self { mean: current_mean, sigma: current_sigma }
     }
 }
 
 impl From<DistributionShiftSerializable> for DistributionShift {
-    fn from(
-        DistributionShiftSerializable { current_mean, current_sigma }: DistributionShiftSerializable,
-    ) -> Self {
-        Self {
-            current_mean: OrderedFloat(current_mean),
-            current_sigma: OrderedFloat(current_sigma),
-        }
+    fn from(DistributionShiftSerializable { mean, sigma }: DistributionShiftSerializable) -> Self {
+        Self { current_mean: OrderedFloat(mean), current_sigma: OrderedFloat(sigma) }
     }
 }
 

milli/src/vector/ollama.rs

@@ -14,11 +14,12 @@ pub struct EmbedderOptions {
     pub embedding_model: String,
     pub url: Option<String>,
     pub api_key: Option<String>,
+    pub distribution: Option<DistributionShift>,
 }
 
 impl EmbedderOptions {
     pub fn with_default_model(api_key: Option<String>, url: Option<String>) -> Self {
-        Self { embedding_model: "nomic-embed-text".into(), api_key, url }
+        Self { embedding_model: "nomic-embed-text".into(), api_key, url, distribution: None }
     }
 }
 
@@ -27,8 +28,8 @@ impl Embedder {
         let model = options.embedding_model.as_str();
         let rest_embedder = match RestEmbedder::new(RestEmbedderOptions {
             api_key: options.api_key,
-            distribution: None,
             dimensions: None,
+            distribution: options.distribution,
             url: options.url.unwrap_or_else(get_ollama_path),
             query: serde_json::json!({
                 "model": model,
@@ -90,7 +91,7 @@ impl Embedder {
     }
 
     pub fn distribution(&self) -> Option<DistributionShift> {
-        None
+        self.rest_embedder.distribution()
     }
 }
 

milli/src/vector/openai.rs

@@ -11,6 +11,7 @@ pub struct EmbedderOptions {
     pub api_key: Option<String>,
     pub embedding_model: EmbeddingModel,
     pub dimensions: Option<usize>,
+    pub distribution: Option<DistributionShift>,
 }
 
 impl EmbedderOptions {
@@ -37,6 +38,10 @@ impl EmbedderOptions {
 
         query
     }
+
+    pub fn distribution(&self) -> Option<DistributionShift> {
+        self.distribution.or(self.embedding_model.distribution())
+    }
 }
 
 #[derive(
@@ -139,11 +144,11 @@ pub const OPENAI_EMBEDDINGS_URL: &str = "https://api.openai.com/v1/embeddings";
 
 impl EmbedderOptions {
     pub fn with_default_model(api_key: Option<String>) -> Self {
-        Self { api_key, embedding_model: Default::default(), dimensions: None }
+        Self { api_key, embedding_model: Default::default(), dimensions: None, distribution: None }
     }
 
     pub fn with_embedding_model(api_key: Option<String>, embedding_model: EmbeddingModel) -> Self {
-        Self { api_key, embedding_model, dimensions: None }
+        Self { api_key, embedding_model, dimensions: None, distribution: None }
     }
 }
 
@@ -170,7 +175,7 @@ impl Embedder {
 
         let rest_embedder = RestEmbedder::new(RestEmbedderOptions {
             api_key: Some(api_key.clone()),
-            distribution: options.embedding_model.distribution(),
+            distribution: None,
             dimensions: Some(options.dimensions()),
             url: OPENAI_EMBEDDINGS_URL.to_owned(),
             query: options.query(),
@@ -256,6 +261,6 @@ impl Embedder {
     }
 
     pub fn distribution(&self) -> Option<DistributionShift> {
-        self.options.embedding_model.distribution()
+        self.options.distribution()
     }
 }

milli/src/vector/settings.rs

@@ -2,7 +2,7 @@ use deserr::Deserr;
 use serde::{Deserialize, Serialize};
 
 use super::rest::InputType;
-use super::{ollama, openai};
+use super::{ollama, openai, DistributionShift};
 use crate::prompt::PromptData;
 use crate::update::Setting;
 use crate::vector::EmbeddingConfig;
@@ -48,6 +48,9 @@ pub struct EmbeddingSettings {
     #[serde(default, skip_serializing_if = "Setting::is_not_set")]
     #[deserr(default)]
     pub input_type: Setting<InputType>,
+    #[serde(default, skip_serializing_if = "Setting::is_not_set")]
+    #[deserr(default)]
+    pub distribution: Setting<DistributionShift>,
 }
 
 pub fn check_unset<T>(
@@ -101,6 +104,8 @@ impl EmbeddingSettings {
     pub const EMBEDDING_OBJECT: &'static str = "embeddingObject";
     pub const INPUT_TYPE: &'static str = "inputType";
 
+    pub const DISTRIBUTION: &'static str = "distribution";
+
     pub fn allowed_sources_for_field(field: &'static str) -> &'static [EmbedderSource] {
         match field {
             Self::SOURCE => &[
@@ -132,6 +137,13 @@ impl EmbeddingSettings {
             Self::PATH_TO_EMBEDDINGS => &[EmbedderSource::Rest],
             Self::EMBEDDING_OBJECT => &[EmbedderSource::Rest],
             Self::INPUT_TYPE => &[EmbedderSource::Rest],
+            Self::DISTRIBUTION => &[
+                EmbedderSource::HuggingFace,
+                EmbedderSource::Ollama,
+                EmbedderSource::OpenAi,
+                EmbedderSource::Rest,
+                EmbedderSource::UserProvided,
+            ],
             _other => unreachable!("unknown field"),
         }
     }
@@ -144,14 +156,24 @@ impl EmbeddingSettings {
                 Self::API_KEY,
                 Self::DOCUMENT_TEMPLATE,
                 Self::DIMENSIONS,
+                Self::DISTRIBUTION,
             ],
-            EmbedderSource::HuggingFace => {
-                &[Self::SOURCE, Self::MODEL, Self::REVISION, Self::DOCUMENT_TEMPLATE]
-            }
-            EmbedderSource::Ollama => {
-                &[Self::SOURCE, Self::MODEL, Self::DOCUMENT_TEMPLATE, Self::URL, Self::API_KEY]
-            }
-            EmbedderSource::UserProvided => &[Self::SOURCE, Self::DIMENSIONS],
+            EmbedderSource::HuggingFace => &[
+                Self::SOURCE,
+                Self::MODEL,
+                Self::REVISION,
+                Self::DOCUMENT_TEMPLATE,
+                Self::DISTRIBUTION,
+            ],
+            EmbedderSource::Ollama => &[
+                Self::SOURCE,
+                Self::MODEL,
+                Self::DOCUMENT_TEMPLATE,
+                Self::URL,
+                Self::API_KEY,
+                Self::DISTRIBUTION,
+            ],
+            EmbedderSource::UserProvided => &[Self::SOURCE, Self::DIMENSIONS, Self::DISTRIBUTION],
             EmbedderSource::Rest => &[
                 Self::SOURCE,
                 Self::API_KEY,
@@ -163,6 +185,7 @@ impl EmbeddingSettings {
                 Self::PATH_TO_EMBEDDINGS,
                 Self::EMBEDDING_OBJECT,
                 Self::INPUT_TYPE,
+                Self::DISTRIBUTION,
             ],
         }
     }
@@ -187,6 +210,66 @@ impl EmbeddingSettings {
             *model = Setting::Set(openai::EmbeddingModel::default().name().to_owned())
         }
     }
+
+    pub(crate) fn apply_and_need_reindex(
+        old: &mut Setting<EmbeddingSettings>,
+        new: Setting<EmbeddingSettings>,
+    ) -> bool {
+        match (old, new) {
+            (
+                Setting::Set(EmbeddingSettings {
+                    source: old_source,
+                    model: old_model,
+                    revision: old_revision,
+                    api_key: old_api_key,
+                    dimensions: old_dimensions,
+                    document_template: old_document_template,
+                    url: old_url,
+                    query: old_query,
+                    input_field: old_input_field,
+                    path_to_embeddings: old_path_to_embeddings,
+                    embedding_object: old_embedding_object,
+                    input_type: old_input_type,
+                    distribution: old_distribution,
+                }),
+                Setting::Set(EmbeddingSettings {
+                    source: new_source,
+                    model: new_model,
+                    revision: new_revision,
+                    api_key: new_api_key,
+                    dimensions: new_dimensions,
+                    document_template: new_document_template,
+                    url: new_url,
+                    query: new_query,
+                    input_field: new_input_field,
+                    path_to_embeddings: new_path_to_embeddings,
+                    embedding_object: new_embedding_object,
+                    input_type: new_input_type,
+                    distribution: new_distribution,
+                }),
+            ) => {
+                let mut needs_reindex = false;
+
+                needs_reindex |= old_source.apply(new_source);
+                needs_reindex |= old_model.apply(new_model);
+                needs_reindex |= old_revision.apply(new_revision);
+                needs_reindex |= old_dimensions.apply(new_dimensions);
+                needs_reindex |= old_document_template.apply(new_document_template);
+                needs_reindex |= old_url.apply(new_url);
+                needs_reindex |= old_query.apply(new_query);
+                needs_reindex |= old_input_field.apply(new_input_field);
+                needs_reindex |= old_path_to_embeddings.apply(new_path_to_embeddings);
+                needs_reindex |= old_embedding_object.apply(new_embedding_object);
+                needs_reindex |= old_input_type.apply(new_input_type);
+
+                old_distribution.apply(new_distribution);
+                old_api_key.apply(new_api_key);
+                needs_reindex
+            }
+            (Setting::Reset, Setting::Reset) | (_, Setting::NotSet) => false,
+            _ => true,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, Default, Serialize, Deserialize, PartialEq, Eq, Deserr)]
@@ -214,58 +297,6 @@ impl std::fmt::Display for EmbedderSource {
     }
 }
 
-impl EmbeddingSettings {
-    pub fn apply(&mut self, new: Self) {
-        let EmbeddingSettings {
-            source,
-            model,
-            revision,
-            api_key,
-            dimensions,
-            document_template,
-            url,
-            query,
-            input_field,
-            path_to_embeddings,
-            embedding_object,
-            input_type,
-        } = new;
-        let old_source = self.source;
-        self.source.apply(source);
-        // Reinitialize the whole setting object on a source change
-        if old_source != self.source {
-            *self = EmbeddingSettings {
-                source,
-                model,
-                revision,
-                api_key,
-                dimensions,
-                document_template,
-                url,
-                query,
-                input_field,
-                path_to_embeddings,
-                embedding_object,
-                input_type,
-            };
-            return;
-        }
-
-        self.model.apply(model);
-        self.revision.apply(revision);
-        self.api_key.apply(api_key);
-        self.dimensions.apply(dimensions);
-        self.document_template.apply(document_template);
-
-        self.url.apply(url);
-        self.query.apply(query);
-        self.input_field.apply(input_field);
-        self.path_to_embeddings.apply(path_to_embeddings);
-        self.embedding_object.apply(embedding_object);
-        self.input_type.apply(input_type);
-    }
-}
-
 impl From<EmbeddingConfig> for EmbeddingSettings {
     fn from(value: EmbeddingConfig) -> Self {
         let EmbeddingConfig { embedder_options, prompt } = value;
@@ -283,6 +314,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings: Setting::NotSet,
                 embedding_object: Setting::NotSet,
                 input_type: Setting::NotSet,
+                distribution: options.distribution.map(Setting::Set).unwrap_or_default(),
             },
             super::EmbedderOptions::OpenAi(options) => Self {
                 source: Setting::Set(EmbedderSource::OpenAi),
@@ -297,6 +329,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings: Setting::NotSet,
                 embedding_object: Setting::NotSet,
                 input_type: Setting::NotSet,
+                distribution: options.distribution.map(Setting::Set).unwrap_or_default(),
             },
             super::EmbedderOptions::Ollama(options) => Self {
                 source: Setting::Set(EmbedderSource::Ollama),
@@ -311,6 +344,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings: Setting::NotSet,
                 embedding_object: Setting::NotSet,
                 input_type: Setting::NotSet,
+                distribution: options.distribution.map(Setting::Set).unwrap_or_default(),
             },
             super::EmbedderOptions::UserProvided(options) => Self {
                 source: Setting::Set(EmbedderSource::UserProvided),
@@ -325,11 +359,10 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings: Setting::NotSet,
                 embedding_object: Setting::NotSet,
                 input_type: Setting::NotSet,
+                distribution: options.distribution.map(Setting::Set).unwrap_or_default(),
             },
             super::EmbedderOptions::Rest(super::rest::EmbedderOptions {
                 api_key,
-                // TODO: support distribution
-                distribution: _,
                 dimensions,
                 url,
                 query,
@@ -337,6 +370,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings,
                 embedding_object,
                 input_type,
+                distribution,
             }) => Self {
                 source: Setting::Set(EmbedderSource::Rest),
                 model: Setting::NotSet,
@@ -350,6 +384,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 path_to_embeddings: Setting::Set(path_to_embeddings),
                 embedding_object: Setting::Set(embedding_object),
                 input_type: Setting::Set(input_type),
+                distribution: distribution.map(Setting::Set).unwrap_or_default(),
             },
         }
     }
@@ -371,7 +406,9 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
             path_to_embeddings,
             embedding_object,
             input_type,
+            distribution,
         } = value;
+
         if let Some(source) = source.set() {
             match source {
                 EmbedderSource::OpenAi => {
@@ -387,6 +424,7 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
                     if let Some(dimensions) = dimensions.set() {
                         options.dimensions = Some(dimensions);
                     }
+                    options.distribution = distribution.set();
                     this.embedder_options = super::EmbedderOptions::OpenAi(options);
                 }
                 EmbedderSource::Ollama => {
@@ -399,6 +437,7 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
                         options.embedding_model = model;
                     }
 
+                    options.distribution = distribution.set();
                     this.embedder_options = super::EmbedderOptions::Ollama(options);
                 }
                 EmbedderSource::HuggingFace => {
@@ -415,12 +454,14 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
                     if let Some(revision) = revision.set() {
                         options.revision = Some(revision);
                     }
+                    options.distribution = distribution.set();
                     this.embedder_options = super::EmbedderOptions::HuggingFace(options);
                 }
                 EmbedderSource::UserProvided => {
                     this.embedder_options =
                         super::EmbedderOptions::UserProvided(super::manual::EmbedderOptions {
                             dimensions: dimensions.set().unwrap(),
+                            distribution: distribution.set(),
                         });
                 }
                 EmbedderSource::Rest => {
@@ -429,7 +470,6 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
                     this.embedder_options =
                         super::EmbedderOptions::Rest(super::rest::EmbedderOptions {
                             api_key: api_key.set(),
-                            distribution: None,
                             dimensions: dimensions.set(),
                             url: url.set().unwrap(),
                             query: query.set().unwrap_or(embedder_options.query),
@@ -441,6 +481,7 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
                                 .set()
                                 .unwrap_or(embedder_options.embedding_object),
                             input_type: input_type.set().unwrap_or(embedder_options.input_type),
+                            distribution: distribution.set(),
                         })
                 }
             }