Change retrieveVectors behavior:

- when the feature is disabled, documents are never modified
- when the feature is enabled and `retrieveVectors` is disabled, `_vectors` is removed from documents
- when the feature is enabled and `retrieveVectors` is enabled, vectors from the vectors DB are merged with `_vectors` in documents

Additionally `_vectors` is never displayed when the `displayedAttributes` list does not contain either `*` or `_vectors`

- fixed an issue where `_vectors` was not injected when all vectors in the dataset where always generated

meilisearch/src/routes/indexes/documents.rs

@@ -40,7 +40,7 @@ use crate::extractors::sequential_extractor::SeqHandler;
 use crate::routes::{
     get_task_id, is_dry_run, PaginationView, SummarizedTaskView, PAGINATION_DEFAULT_LIMIT,
 };
-use crate::search::parse_filter;
+use crate::search::{parse_filter, RetrieveVectors};
 use crate::Opt;
 
 static ACCEPTED_CONTENT_TYPE: Lazy<Vec<String>> = Lazy::new(|| {
@@ -110,21 +110,20 @@ pub async fn get_document(
     debug!(parameters = ?params, "Get document");
     let index_uid = IndexUid::try_from(index_uid)?;
 
-    let GetDocument { fields, retrieve_vectors } = params.into_inner();
+    let GetDocument { fields, retrieve_vectors: param_retrieve_vectors } = params.into_inner();
     let attributes_to_retrieve = fields.merge_star_and_none();
 
     let features = index_scheduler.features();
-    if retrieve_vectors.0 {
+    let retrieve_vectors = RetrieveVectors::new(param_retrieve_vectors.0, features)?;
-        features.check_vector("Passing `retrieveVectors` as a parameter")?;
+
-    }
     analytics.get_fetch_documents(
-        &DocumentFetchKind::PerDocumentId { retrieve_vectors: retrieve_vectors.0 },
+        &DocumentFetchKind::PerDocumentId { retrieve_vectors: param_retrieve_vectors.0 },
         &req,
     );
 
     let index = index_scheduler.index(&index_uid)?;
     let document =
-        retrieve_document(&index, &document_id, attributes_to_retrieve, retrieve_vectors.0)?;
+        retrieve_document(&index, &document_id, attributes_to_retrieve, retrieve_vectors)?;
     debug!(returns = ?document, "Get document");
     Ok(HttpResponse::Ok().json(document))
 }
@@ -195,11 +194,6 @@ pub async fn documents_by_query_post(
     let body = body.into_inner();
     debug!(parameters = ?body, "Get documents POST");
 
-    let features = index_scheduler.features();
-    if body.retrieve_vectors {
-        features.check_vector("Passing `retrieveVectors` as a parameter")?;
-    }
-
     analytics.post_fetch_documents(
         &DocumentFetchKind::Normal {
             with_filter: body.filter.is_some(),
@@ -224,11 +218,6 @@ pub async fn get_documents(
 
     let BrowseQueryGet { limit, offset, fields, retrieve_vectors, filter } = params.into_inner();
 
-    let features = index_scheduler.features();
-    if retrieve_vectors.0 {
-        features.check_vector("Passing `retrieveVectors` as a parameter")?;
-    }
-
     let filter = match filter {
         Some(f) => match serde_json::from_str(&f) {
             Ok(v) => Some(v),
@@ -266,6 +255,9 @@ fn documents_by_query(
     let index_uid = IndexUid::try_from(index_uid.into_inner())?;
     let BrowseQuery { offset, limit, fields, retrieve_vectors, filter } = query;
 
+    let features = index_scheduler.features();
+    let retrieve_vectors = RetrieveVectors::new(retrieve_vectors, features)?;
+
     let index = index_scheduler.index(&index_uid)?;
     let (total, documents) =
         retrieve_documents(&index, offset, limit, filter, fields, retrieve_vectors)?;
@@ -608,7 +600,7 @@ fn some_documents<'a, 't: 'a>(
     index: &'a Index,
     rtxn: &'t RoTxn,
     doc_ids: impl IntoIterator<Item = DocumentId> + 'a,
-    retrieve_vectors: bool,
+    retrieve_vectors: RetrieveVectors,
 ) -> Result<impl Iterator<Item = Result<Document, ResponseError>> + 'a, ResponseError> {
     let fields_ids_map = index.fields_ids_map(rtxn)?;
     let all_fields: Vec<_> = fields_ids_map.iter().map(|(id, _)| id).collect();
@@ -617,9 +609,16 @@ fn some_documents<'a, 't: 'a>(
     Ok(index.iter_documents(rtxn, doc_ids)?.map(move |ret| {
         ret.map_err(ResponseError::from).and_then(|(key, document)| -> Result<_, ResponseError> {
             let mut document = milli::obkv_to_json(&all_fields, &fields_ids_map, document)?;
-
+            match retrieve_vectors {
-            if retrieve_vectors {
+                RetrieveVectors::Ignore => {}
-                let mut vectors = serde_json::Map::new();
+                RetrieveVectors::Hide => {
+                    document.remove("_vectors");
+                }
+                RetrieveVectors::Retrieve => {
+                    let mut vectors = match document.remove("_vectors") {
+                        Some(Value::Object(map)) => map,
+                        _ => Default::default(),
+                    };
                     for (name, vector) in index.embeddings(rtxn, key)? {
                         let user_provided = embedding_configs
                             .iter()
@@ -636,6 +635,7 @@ fn some_documents<'a, 't: 'a>(
                     }
                     document.insert("_vectors".into(), vectors.into());
                 }
+            }
 
             Ok(document)
         })
@@ -648,7 +648,7 @@ fn retrieve_documents<S: AsRef<str>>(
     limit: usize,
     filter: Option<Value>,
     attributes_to_retrieve: Option<Vec<S>>,
-    retrieve_vectors: bool,
+    retrieve_vectors: RetrieveVectors,
 ) -> Result<(u64, Vec<Document>), ResponseError> {
     let rtxn = index.read_txn()?;
     let filter = &filter;
@@ -688,10 +688,9 @@ fn retrieve_documents<S: AsRef<str>>(
             Ok(match &attributes_to_retrieve {
                 Some(attributes_to_retrieve) => permissive_json_pointer::select_values(
                     &document?,
-                    attributes_to_retrieve
+                    attributes_to_retrieve.iter().map(|s| s.as_ref()).chain(
-                        .iter()
+                        (retrieve_vectors == RetrieveVectors::Retrieve).then_some("_vectors"),
-                        .map(|s| s.as_ref())
+                    ),
-                        .chain(retrieve_vectors.then_some("_vectors")),
                 ),
                 None => document?,
             })
@@ -705,7 +704,7 @@ fn retrieve_document<S: AsRef<str>>(
     index: &Index,
     doc_id: &str,
     attributes_to_retrieve: Option<Vec<S>>,
-    retrieve_vectors: bool,
+    retrieve_vectors: RetrieveVectors,
 ) -> Result<Document, ResponseError> {
     let txn = index.read_txn()?;
 
@@ -724,7 +723,7 @@ fn retrieve_document<S: AsRef<str>>(
             attributes_to_retrieve
                 .iter()
                 .map(|s| s.as_ref())
-                .chain(retrieve_vectors.then_some("_vectors")),
+                .chain((retrieve_vectors == RetrieveVectors::Retrieve).then_some("_vectors")),
         ),
         None => document,
     };

meilisearch/src/routes/indexes/search.rs

@@ -20,9 +20,9 @@ use crate::extractors::sequential_extractor::SeqHandler;
 use crate::metrics::MEILISEARCH_DEGRADED_SEARCH_REQUESTS;
 use crate::search::{
     add_search_rules, perform_search, HybridQuery, MatchingStrategy, RankingScoreThreshold,
-    SearchKind, SearchQuery, SemanticRatio, DEFAULT_CROP_LENGTH, DEFAULT_CROP_MARKER,
+    RetrieveVectors, SearchKind, SearchQuery, SemanticRatio, DEFAULT_CROP_LENGTH,
-    DEFAULT_HIGHLIGHT_POST_TAG, DEFAULT_HIGHLIGHT_PRE_TAG, DEFAULT_SEARCH_LIMIT,
+    DEFAULT_CROP_MARKER, DEFAULT_HIGHLIGHT_POST_TAG, DEFAULT_HIGHLIGHT_PRE_TAG,
-    DEFAULT_SEARCH_OFFSET, DEFAULT_SEMANTIC_RATIO,
+    DEFAULT_SEARCH_LIMIT, DEFAULT_SEARCH_OFFSET, DEFAULT_SEMANTIC_RATIO,
 };
 use crate::search_queue::SearchQueue;
 
@@ -225,10 +225,12 @@ pub async fn search_with_url_query(
     let features = index_scheduler.features();
 
     let search_kind = search_kind(&query, index_scheduler.get_ref(), &index, features)?;
-
+    let retrieve_vector = RetrieveVectors::new(query.retrieve_vectors, features)?;
     let _permit = search_queue.try_get_search_permit().await?;
-    let search_result =
+    let search_result = tokio::task::spawn_blocking(move || {
-        tokio::task::spawn_blocking(move || perform_search(&index, query, search_kind)).await?;
+        perform_search(&index, query, search_kind, retrieve_vector)
+    })
+    .await?;
     if let Ok(ref search_result) = search_result {
         aggregate.succeed(search_result);
     }
@@ -265,10 +267,13 @@ pub async fn search_with_post(
     let features = index_scheduler.features();
 
     let search_kind = search_kind(&query, index_scheduler.get_ref(), &index, features)?;
+    let retrieve_vectors = RetrieveVectors::new(query.retrieve_vectors, features)?;
 
     let _permit = search_queue.try_get_search_permit().await?;
-    let search_result =
+    let search_result = tokio::task::spawn_blocking(move || {
-        tokio::task::spawn_blocking(move || perform_search(&index, query, search_kind)).await?;
+        perform_search(&index, query, search_kind, retrieve_vectors)
+    })
+    .await?;
     if let Ok(ref search_result) = search_result {
         aggregate.succeed(search_result);
         if search_result.degraded {
@@ -295,9 +300,6 @@ pub fn search_kind(
     if query.hybrid.is_some() {
         features.check_vector("Passing `hybrid` as a parameter")?;
     }
-    if query.retrieve_vectors {
-        features.check_vector("Passing `retrieveVectors` as a parameter")?;
-    }
 
     // regardless of anything, always do a keyword search when we don't have a vector and the query is whitespace or missing
     if query.vector.is_none() {

meilisearch/src/routes/indexes/similar.rs

@@ -17,8 +17,8 @@ use crate::analytics::{Analytics, SimilarAggregator};
 use crate::extractors::authentication::GuardedData;
 use crate::extractors::sequential_extractor::SeqHandler;
 use crate::search::{
-    add_search_rules, perform_similar, RankingScoreThresholdSimilar, SearchKind, SimilarQuery,
+    add_search_rules, perform_similar, RankingScoreThresholdSimilar, RetrieveVectors, SearchKind,
-    SimilarResult, DEFAULT_SEARCH_LIMIT, DEFAULT_SEARCH_OFFSET,
+    SimilarQuery, SimilarResult, DEFAULT_SEARCH_LIMIT, DEFAULT_SEARCH_OFFSET,
 };
 
 pub fn configure(cfg: &mut web::ServiceConfig) {
@@ -93,6 +93,8 @@ async fn similar(
 
     features.check_vector("Using the similar API")?;
 
+    let retrieve_vectors = RetrieveVectors::new(query.retrieve_vectors, features)?;
+
     // Tenant token search_rules.
     if let Some(search_rules) = index_scheduler.filters().get_index_search_rules(&index_uid) {
         add_search_rules(&mut query.filter, search_rules);
@@ -103,7 +105,9 @@ async fn similar(
     let (embedder_name, embedder) =
         SearchKind::embedder(&index_scheduler, &index, query.embedder.as_deref(), None)?;
 
-    tokio::task::spawn_blocking(move || perform_similar(&index, query, embedder_name, embedder))
+    tokio::task::spawn_blocking(move || {
+        perform_similar(&index, query, embedder_name, embedder, retrieve_vectors)
+    })
     .await?
 }
 

meilisearch/src/routes/multi_search.rs

@@ -15,7 +15,7 @@ use crate::extractors::authentication::{AuthenticationError, GuardedData};
 use crate::extractors::sequential_extractor::SeqHandler;
 use crate::routes::indexes::search::search_kind;
 use crate::search::{
-    add_search_rules, perform_search, SearchQueryWithIndex, SearchResultWithIndex,
+    add_search_rules, perform_search, RetrieveVectors, SearchQueryWithIndex, SearchResultWithIndex,
 };
 use crate::search_queue::SearchQueue;
 
@@ -83,9 +83,12 @@ pub async fn multi_search_with_post(
 
             let search_kind = search_kind(&query, index_scheduler.get_ref(), &index, features)
                 .with_index(query_index)?;
+            let retrieve_vector =
+                RetrieveVectors::new(query.retrieve_vectors, features).with_index(query_index)?;
 
-            let search_result =
+            let search_result = tokio::task::spawn_blocking(move || {
-                tokio::task::spawn_blocking(move || perform_search(&index, query, search_kind))
+                perform_search(&index, query, search_kind, retrieve_vector)
+            })
             .await
             .with_index(query_index)?;
 

meilisearch/src/search.rs

@@ -823,6 +823,7 @@ pub fn perform_search(
     index: &Index,
     query: SearchQuery,
     search_kind: SearchKind,
+    retrieve_vectors: RetrieveVectors,
 ) -> Result<SearchResult, MeilisearchHttpError> {
     let before_search = Instant::now();
     let rtxn = index.read_txn()?;
@@ -860,7 +861,8 @@ pub fn perform_search(
         page,
         hits_per_page,
         attributes_to_retrieve,
-        retrieve_vectors,
+        // use the enum passed as parameter
+        retrieve_vectors: _,
         attributes_to_crop,
         crop_length,
         attributes_to_highlight,
@@ -968,7 +970,7 @@ pub fn perform_search(
 
 struct AttributesFormat {
     attributes_to_retrieve: Option<BTreeSet<String>>,
-    retrieve_vectors: bool,
+    retrieve_vectors: RetrieveVectors,
     attributes_to_highlight: Option<HashSet<String>>,
     attributes_to_crop: Option<Vec<String>>,
     crop_length: usize,
@@ -981,6 +983,36 @@ struct AttributesFormat {
     show_ranking_score_details: bool,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum RetrieveVectors {
+    /// Do not touch the `_vectors` field
+    ///
+    /// this is the behavior when the vectorStore feature is disabled
+    Ignore,
+    /// Remove the `_vectors` field
+    ///
+    /// this is the behavior when the vectorStore feature is enabled, and `retrieveVectors` is `false`
+    Hide,
+    /// Retrieve vectors from the DB and merge them into the `_vectors` field
+    ///
+    /// this is the behavior when the vectorStore feature is enabled, and `retrieveVectors` is `true`
+    Retrieve,
+}
+
+impl RetrieveVectors {
+    pub fn new(
+        retrieve_vector: bool,
+        features: index_scheduler::RoFeatures,
+    ) -> Result<Self, index_scheduler::Error> {
+        match (retrieve_vector, features.check_vector("Passing `retrieveVectors` as a parameter")) {
+            (true, Ok(())) => Ok(Self::Retrieve),
+            (true, Err(error)) => Err(error),
+            (false, Ok(())) => Ok(Self::Hide),
+            (false, Err(_)) => Ok(Self::Ignore),
+        }
+    }
+}
+
 fn make_hits(
     index: &Index,
     rtxn: &RoTxn<'_>,
@@ -990,10 +1022,32 @@ fn make_hits(
     document_scores: Vec<Vec<ScoreDetails>>,
 ) -> Result<Vec<SearchHit>, MeilisearchHttpError> {
     let fields_ids_map = index.fields_ids_map(rtxn).unwrap();
-    let displayed_ids = index
+    let displayed_ids =
-        .displayed_fields_ids(rtxn)?
+        index.displayed_fields_ids(rtxn)?.map(|fields| fields.into_iter().collect::<BTreeSet<_>>());
-        .map(|fields| fields.into_iter().collect::<BTreeSet<_>>())
+
-        .unwrap_or_else(|| fields_ids_map.iter().map(|(id, _)| id).collect());
+    let vectors_fid = fields_ids_map.id(milli::vector::parsed_vectors::RESERVED_VECTORS_FIELD_NAME);
+
+    let vectors_is_hidden = match (&displayed_ids, vectors_fid) {
+        // displayed_ids is a wildcard, so `_vectors` can be displayed regardless of its fid
+        (None, _) => false,
+        // displayed_ids is a finite list, and `_vectors` cannot be part of it because it is not an existing field
+        (Some(_), None) => true,
+        // displayed_ids is a finit list, so hide if `_vectors` is not part of it
+        (Some(map), Some(vectors_fid)) => map.contains(&vectors_fid),
+    };
+
+    let retrieve_vectors = if let RetrieveVectors::Retrieve = format.retrieve_vectors {
+        if vectors_is_hidden {
+            RetrieveVectors::Hide
+        } else {
+            RetrieveVectors::Retrieve
+        }
+    } else {
+        format.retrieve_vectors
+    };
+
+    let displayed_ids =
+        displayed_ids.unwrap_or_else(|| fields_ids_map.iter().map(|(id, _)| id).collect());
     let fids = |attrs: &BTreeSet<String>| {
         let mut ids = BTreeSet::new();
         for attr in attrs {
@@ -1016,9 +1070,7 @@ fn make_hits(
         .intersection(&displayed_ids)
         .cloned()
         .collect();
-    let is_vectors_displayed =
+
-        fields_ids_map.id("_vectors").is_some_and(|fid| displayed_ids.contains(&fid));
-    let retrieve_vectors = format.retrieve_vectors && is_vectors_displayed;
     let attr_to_highlight = format.attributes_to_highlight.unwrap_or_default();
     let attr_to_crop = format.attributes_to_crop.unwrap_or_default();
     let formatted_options = compute_formatted_options(
@@ -1058,15 +1110,30 @@ fn make_hits(
         // First generate a document with all the displayed fields
         let displayed_document = make_document(&displayed_ids, &fields_ids_map, obkv)?;
 
+        let add_vectors_fid =
+            vectors_fid.filter(|_fid| retrieve_vectors == RetrieveVectors::Retrieve);
+
         // select the attributes to retrieve
         let attributes_to_retrieve = to_retrieve_ids
             .iter()
+            // skip the vectors_fid if RetrieveVectors::Hide
+            .filter(|fid| match vectors_fid {
+                Some(vectors_fid) => {
+                    !(retrieve_vectors == RetrieveVectors::Hide && **fid == vectors_fid)
+                }
+                None => true,
+            })
+            // need to retrieve the existing `_vectors` field if the `RetrieveVectors::Retrieve`
+            .chain(add_vectors_fid.iter())
             .map(|&fid| fields_ids_map.name(fid).expect("Missing field name"));
         let mut document =
             permissive_json_pointer::select_values(&displayed_document, attributes_to_retrieve);
 
-        if retrieve_vectors {
+        if retrieve_vectors == RetrieveVectors::Retrieve {
-            let mut vectors = serde_json::Map::new();
+            let mut vectors = match document.remove("_vectors") {
+                Some(Value::Object(map)) => map,
+                _ => Default::default(),
+            };
             for (name, vector) in index.embeddings(rtxn, id)? {
                 let user_provided = embedding_configs
                     .iter()
@@ -1148,6 +1215,7 @@ pub fn perform_similar(
     query: SimilarQuery,
     embedder_name: String,
     embedder: Arc<Embedder>,
+    retrieve_vectors: RetrieveVectors,
 ) -> Result<SimilarResult, ResponseError> {
     let before_search = Instant::now();
     let rtxn = index.read_txn()?;
@@ -1159,7 +1227,7 @@ pub fn perform_similar(
         filter: _,
         embedder: _,
         attributes_to_retrieve,
-        retrieve_vectors,
+        retrieve_vectors: _,
         show_ranking_score,
         show_ranking_score_details,
         ranking_score_threshold,