implement the binary quantization in meilisearch

Cargo.lock

@@ -384,6 +384,24 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96d30a06541fbafbc7f82ed10c06164cfbd2c401138f6addd8404629c4b16711"
 
+[[package]]
+name = "arroy"
+version = "0.4.0"
+dependencies = [
+ "bytemuck",
+ "byteorder",
+ "heed",
+ "log",
+ "memmap2",
+ "nohash",
+ "ordered-float",
+ "rand",
+ "rayon",
+ "roaring",
+ "tempfile",
+ "thiserror",
+]
+
 [[package]]
 name = "arroy"
 version = "0.4.0"
@@ -2555,7 +2573,7 @@ name = "index-scheduler"
 version = "1.11.0"
 dependencies = [
  "anyhow",
- "arroy",
+ "arroy 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "big_s",
  "bincode",
  "crossbeam",
@@ -2838,7 +2856,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e310b3a6b5907f99202fcdb4960ff45b93735d7c7d96b760fcff8db2dc0e103d"
 dependencies = [
  "cfg-if",
- "windows-targets 0.48.1",
+ "windows-targets 0.52.4",
 ]
 
 [[package]]
@@ -3545,7 +3563,7 @@ dependencies = [
 name = "milli"
 version = "1.11.0"
 dependencies = [
- "arroy",
+ "arroy 0.4.0",
  "big_s",
  "bimap",
  "bincode",
@@ -3686,6 +3704,12 @@ version = "0.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6d02c0b00610773bb7fc61d85e13d86c7858cbdf00e1a120bfc41bc055dbaa0e"
 
+[[package]]
+name = "nohash"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a0f889fb66f7acdf83442c35775764b51fed3c606ab9cee51500dbde2cf528ca"
+
 [[package]]
 name = "nom"
 version = "7.1.3"

index-scheduler/src/lib.rs

@@ -1477,7 +1477,7 @@ impl IndexScheduler {
             .map(
                 |IndexEmbeddingConfig {
                      name,
-                     config: milli::vector::EmbeddingConfig { embedder_options, prompt },
+                     config: milli::vector::EmbeddingConfig { embedder_options, prompt, quantized },
                      ..
                  }| {
                     let prompt =
@@ -1486,7 +1486,10 @@ impl IndexScheduler {
                     {
                         let embedders = self.embedders.read().unwrap();
                         if let Some(embedder) = embedders.get(&embedder_options) {
-                            return Ok((name, (embedder.clone(), prompt)));
+                            return Ok((
+                                name,
+                                (embedder.clone(), prompt, quantized.unwrap_or_default()),
+                            ));
                         }
                     }
 
@@ -1500,7 +1503,7 @@ impl IndexScheduler {
                         let mut embedders = self.embedders.write().unwrap();
                         embedders.insert(embedder_options, embedder.clone());
                     }
-                    Ok((name, (embedder, prompt)))
+                    Ok((name, (embedder, prompt, quantized.unwrap_or_default())))
                 },
             )
             .collect();
@@ -5197,7 +5200,7 @@ mod tests {
             let simple_hf_name = name.clone();
 
             let configs = index_scheduler.embedders(configs).unwrap();
-            let (hf_embedder, _) = configs.get(&simple_hf_name).unwrap();
+            let (hf_embedder, _, _) = configs.get(&simple_hf_name).unwrap();
             let beagle_embed = hf_embedder.embed_one(S("Intel the beagle best doggo")).unwrap();
             let lab_embed = hf_embedder.embed_one(S("Max the lab best doggo")).unwrap();
             let patou_embed = hf_embedder.embed_one(S("kefir the patou best doggo")).unwrap();

meilisearch-types/src/error.rs

@@ -395,7 +395,10 @@ impl ErrorCode for milli::Error {
                     | UserError::InvalidSettingsDimensions { .. }
                     | UserError::InvalidUrl { .. }
                     | UserError::InvalidSettingsDocumentTemplateMaxBytes { .. }
-                    | UserError::InvalidPrompt(_) => Code::InvalidSettingsEmbedders,
+                    | UserError::InvalidPrompt(_)
+                    | UserError::InvalidDisableBinaryQuantization { .. } => {
+                        Code::InvalidSettingsEmbedders
+                    }
                     UserError::TooManyEmbedders(_) => Code::InvalidSettingsEmbedders,
                     UserError::InvalidPromptForEmbeddings(..) => Code::InvalidSettingsEmbedders,
                     UserError::NoPrimaryKeyCandidateFound => Code::IndexPrimaryKeyNoCandidateFound,

meilisearch/src/routes/indexes/similar.rs

@@ -102,8 +102,8 @@ async fn similar(
 
     let index = index_scheduler.index(&index_uid)?;
 
-    let (embedder_name, embedder) =
+    let (embedder_name, embedder, quantized) =
-        SearchKind::embedder(&index_scheduler, &index, &query.embedder, None)?;
+        SearchKind::embedder(&index_scheduler, &index, query.embedder.as_deref(), None)?;
 
     tokio::task::spawn_blocking(move || {
         perform_similar(
@@ -111,6 +111,7 @@ async fn similar(
             query,
             embedder_name,
             embedder,
+            quantized,
             retrieve_vectors,
             index_scheduler.features(),
         )

meilisearch/src/search/mod.rs

@@ -274,8 +274,8 @@ pub struct HybridQuery {
 #[derive(Clone)]
 pub enum SearchKind {
     KeywordOnly,
-    SemanticOnly { embedder_name: String, embedder: Arc<Embedder> },
+    SemanticOnly { embedder_name: String, embedder: Arc<Embedder>, quantized: bool },
-    Hybrid { embedder_name: String, embedder: Arc<Embedder>, semantic_ratio: f32 },
+    Hybrid { embedder_name: String, embedder: Arc<Embedder>, quantized: bool, semantic_ratio: f32 },
 }
 
 impl SearchKind {
@@ -285,9 +285,9 @@ impl SearchKind {
         embedder_name: &str,
         vector_len: Option<usize>,
     ) -> Result<Self, ResponseError> {
-        let (embedder_name, embedder) =
+        let (embedder_name, embedder, quantized) =
             Self::embedder(index_scheduler, index, embedder_name, vector_len)?;
-        Ok(Self::SemanticOnly { embedder_name, embedder })
+        Ok(Self::SemanticOnly { embedder_name, embedder, quantized })
     }
 
     pub(crate) fn hybrid(
@@ -297,9 +297,9 @@ impl SearchKind {
         semantic_ratio: f32,
         vector_len: Option<usize>,
     ) -> Result<Self, ResponseError> {
-        let (embedder_name, embedder) =
+        let (embedder_name, embedder, quantized) =
             Self::embedder(index_scheduler, index, embedder_name, vector_len)?;
-        Ok(Self::Hybrid { embedder_name, embedder, semantic_ratio })
+        Ok(Self::Hybrid { embedder_name, embedder, quantized, semantic_ratio })
     }
 
     pub(crate) fn embedder(
@@ -307,16 +307,14 @@ impl SearchKind {
         index: &Index,
         embedder_name: &str,
         vector_len: Option<usize>,
-    ) -> Result<(String, Arc<Embedder>), ResponseError> {
+    ) -> Result<(String, Arc<Embedder>, bool), ResponseError> {
         let embedder_configs = index.embedding_configs(&index.read_txn()?)?;
         let embedders = index_scheduler.embedders(embedder_configs)?;
 
-        let embedder = embedders.get(embedder_name);
+        let (embedder, _, quantized) = embedders
-
+            .get(embedder_name)
-        let embedder = embedder
             .ok_or(milli::UserError::InvalidEmbedder(embedder_name.to_owned()))
-            .map_err(milli::Error::from)?
+            .map_err(milli::Error::from)?;
-            .0;
 
         if let Some(vector_len) = vector_len {
             if vector_len != embedder.dimensions() {
@@ -330,7 +328,7 @@ impl SearchKind {
             }
         }
 
-        Ok((embedder_name.to_owned(), embedder))
+        Ok((embedder_name.to_owned(), embedder, quantized))
     }
 }
 
@@ -791,7 +789,7 @@ fn prepare_search<'t>(
                 search.query(q);
             }
         }
-        SearchKind::SemanticOnly { embedder_name, embedder } => {
+        SearchKind::SemanticOnly { embedder_name, embedder, quantized } => {
             let vector = match query.vector.clone() {
                 Some(vector) => vector,
                 None => {
@@ -805,14 +803,19 @@ fn prepare_search<'t>(
                 }
             };
 
-            search.semantic(embedder_name.clone(), embedder.clone(), Some(vector));
+            search.semantic(embedder_name.clone(), embedder.clone(), *quantized, Some(vector));
         }
-        SearchKind::Hybrid { embedder_name, embedder, semantic_ratio: _ } => {
+        SearchKind::Hybrid { embedder_name, embedder, quantized, semantic_ratio: _ } => {
             if let Some(q) = &query.q {
                 search.query(q);
             }
             // will be embedded in hybrid search if necessary
-            search.semantic(embedder_name.clone(), embedder.clone(), query.vector.clone());
+            search.semantic(
+                embedder_name.clone(),
+                embedder.clone(),
+                *quantized,
+                query.vector.clone(),
+            );
         }
     }
 
@@ -1441,6 +1444,7 @@ pub fn perform_similar(
     query: SimilarQuery,
     embedder_name: String,
     embedder: Arc<Embedder>,
+    quantized: bool,
     retrieve_vectors: RetrieveVectors,
     features: RoFeatures,
 ) -> Result<SimilarResult, ResponseError> {
@@ -1469,8 +1473,16 @@ pub fn perform_similar(
         ));
     };
 
-    let mut similar =
+    let mut similar = milli::Similar::new(
-        milli::Similar::new(internal_id, offset, limit, index, &rtxn, embedder_name, embedder);
+        internal_id,
+        offset,
+        limit,
+        index,
+        &rtxn,
+        embedder_name,
+        embedder,
+        quantized,
+    );
 
     if let Some(ref filter) = query.filter {
         if let Some(facets) = parse_filter(filter, Code::InvalidSimilarFilter, features)? {

milli/Cargo.toml

@@ -80,7 +80,8 @@ hf-hub = { git = "https://github.com/dureuill/hf-hub.git", branch = "rust_tls",
 tiktoken-rs = "0.5.9"
 liquid = "0.26.6"
 rhai = { version = "1.19.0", features = ["serde", "no_module", "no_custom_syntax", "no_time", "sync"] }
-arroy = "0.4.0"
+# arroy = "0.4.0"
+arroy = { path = "../../arroy" }
 rand = "0.8.5"
 tracing = "0.1.40"
 ureq = { version = "2.10.0", features = ["json"] }

milli/src/error.rs

@@ -258,6 +258,10 @@ only composed of alphanumeric characters (a-z A-Z 0-9), hyphens (-) and undersco
     },
     #[error("`.embedders.{embedder_name}.dimensions`: `dimensions` cannot be zero")]
     InvalidSettingsDimensions { embedder_name: String },
+    #[error(
+        "`.embedders.{embedder_name}.binaryQuantized`: Cannot disable the binary quantization"
+    )]
+    InvalidDisableBinaryQuantization { embedder_name: String },
     #[error("`.embedders.{embedder_name}.documentTemplateMaxBytes`: `documentTemplateMaxBytes` cannot be zero")]
     InvalidSettingsDocumentTemplateMaxBytes { embedder_name: String },
     #[error("`.embedders.{embedder_name}.url`: could not parse `{url}`: {inner_error}")]

milli/src/index.rs

@@ -21,7 +21,7 @@ use crate::heed_codec::{BEU16StrCodec, FstSetCodec, StrBEU16Codec, StrRefCodec};
 use crate::order_by_map::OrderByMap;
 use crate::proximity::ProximityPrecision;
 use crate::vector::parsed_vectors::RESERVED_VECTORS_FIELD_NAME;
-use crate::vector::{Embedding, EmbeddingConfig};
+use crate::vector::{ArroyReader, Embedding, EmbeddingConfig};
 use crate::{
     default_criteria, CboRoaringBitmapCodec, Criterion, DocumentId, ExternalDocumentsIds,
     FacetDistribution, FieldDistribution, FieldId, FieldIdMapMissingEntry, FieldIdWordCountCodec,
@@ -162,7 +162,7 @@ pub struct Index {
     /// Maps an embedder name to its id in the arroy store.
     pub embedder_category_id: Database<Str, U8>,
     /// Vector store based on arroy™.
-    pub vector_arroy: arroy::Database<arroy::distances::Angular>,
+    pub vector_arroy: arroy::Database<Unspecified>,
 
     /// Maps the document id to the document as an obkv store.
     pub(crate) documents: Database<BEU32, ObkvCodec>,
@@ -1612,18 +1612,11 @@ impl Index {
 
     pub fn arroy_readers<'a>(
         &'a self,
-        rtxn: &'a RoTxn<'a>,
         embedder_id: u8,
-    ) -> impl Iterator<Item = Result<arroy::Reader<'a, arroy::distances::Angular>>> + 'a {
+        quantized: bool,
-        crate::vector::arroy_db_range_for_embedder(embedder_id).map_while(move |k| {
+    ) -> impl Iterator<Item = ArroyReader> + 'a {
-            arroy::Reader::open(rtxn, k, self.vector_arroy)
+        crate::vector::arroy_db_range_for_embedder(embedder_id)
-                .map(Some)
+            .map_while(move |k| Some(ArroyReader::new(self.vector_arroy, k, quantized)))
-                .or_else(|e| match e {
-                    arroy::Error::MissingMetadata(_) => Ok(None),
-                    e => Err(e.into()),
-                })
-                .transpose()
-        })
     }
 
     pub(crate) fn put_search_cutoff(&self, wtxn: &mut RwTxn<'_>, cutoff: u64) -> heed::Result<()> {
@@ -1644,32 +1637,28 @@ impl Index {
         docid: DocumentId,
     ) -> Result<BTreeMap<String, Vec<Embedding>>> {
         let mut res = BTreeMap::new();
-        for row in self.embedder_category_id.iter(rtxn)? {
+        let embedding_configs = self.embedding_configs(rtxn)?;
-            let (embedder_name, embedder_id) = row?;
+        for config in embedding_configs {
+            // TODO: return internal error instead
+            let embedder_id = self.embedder_category_id.get(rtxn, &config.name)?.unwrap();
             let embedder_id = (embedder_id as u16) << 8;
+
             let mut embeddings = Vec::new();
             'vectors: for i in 0..=u8::MAX {
-                let reader = arroy::Reader::open(rtxn, embedder_id | (i as u16), self.vector_arroy)
+                let reader = ArroyReader::new(
-                    .map(Some)
+                    self.vector_arroy,
-                    .or_else(|e| match e {
+                    embedder_id | (i as u16),
-                        arroy::Error::MissingMetadata(_) => Ok(None),
+                    config.config.quantized(),
-                        e => Err(e),
+                );
-                    })
+                match reader.item_vector(rtxn, docid) {
-                    .transpose();
+                    Err(arroy::Error::MissingMetadata(_)) => break 'vectors,
-
+                    Err(err) => return Err(err.into()),
-                let Some(reader) = reader else {
+                    Ok(None) => break 'vectors,
-                    break 'vectors;
+                    Ok(Some(embedding)) => embeddings.push(embedding),
                 };
-
-                let embedding = reader?.item_vector(rtxn, docid)?;
-                if let Some(embedding) = embedding {
-                    embeddings.push(embedding)
-                } else {
-                    break 'vectors;
-                }
             }
 
-            res.insert(embedder_name.to_owned(), embeddings);
+            res.insert(config.name.to_owned(), embeddings);
         }
         Ok(res)
     }

milli/src/search/hybrid.rs

@@ -190,7 +190,7 @@ impl<'a> Search<'a> {
             return Ok(return_keyword_results(self.limit, self.offset, keyword_results));
         };
         // no embedder, no semantic search
-        let Some(SemanticSearch { vector, embedder_name, embedder }) = semantic else {
+        let Some(SemanticSearch { vector, embedder_name, embedder, quantized }) = semantic else {
             return Ok(return_keyword_results(self.limit, self.offset, keyword_results));
         };
 
@@ -212,7 +212,7 @@ impl<'a> Search<'a> {
         };
 
         search.semantic =
-            Some(SemanticSearch { vector: Some(vector_query), embedder_name, embedder });
+            Some(SemanticSearch { vector: Some(vector_query), embedder_name, embedder, quantized });
 
         // TODO: would be better to have two distinct functions at this point
         let vector_results = search.execute()?;

milli/src/search/mod.rs

@@ -32,6 +32,7 @@ pub struct SemanticSearch {
     vector: Option<Vec<f32>>,
     embedder_name: String,
     embedder: Arc<Embedder>,
+    quantized: bool,
 }
 
 pub struct Search<'a> {
@@ -89,9 +90,10 @@ impl<'a> Search<'a> {
         &mut self,
         embedder_name: String,
         embedder: Arc<Embedder>,
+        quantized: bool,
         vector: Option<Vec<f32>>,
     ) -> &mut Search<'a> {
-        self.semantic = Some(SemanticSearch { embedder_name, embedder, vector });
+        self.semantic = Some(SemanticSearch { embedder_name, embedder, quantized, vector });
         self
     }
 
@@ -206,7 +208,7 @@ impl<'a> Search<'a> {
             degraded,
             used_negative_operator,
         } = match self.semantic.as_ref() {
-            Some(SemanticSearch { vector: Some(vector), embedder_name, embedder }) => {
+            Some(SemanticSearch { vector: Some(vector), embedder_name, embedder, quantized }) => {
                 execute_vector_search(
                     &mut ctx,
                     vector,
@@ -219,6 +221,7 @@ impl<'a> Search<'a> {
                     self.limit,
                     embedder_name,
                     embedder,
+                    *quantized,
                     self.time_budget.clone(),
                     self.ranking_score_threshold,
                 )?

milli/src/search/new/mod.rs

@@ -320,6 +320,7 @@ fn get_ranking_rules_for_vector<'ctx>(
     target: &[f32],
     embedder_name: &str,
     embedder: &Embedder,
+    quantized: bool,
 ) -> Result<Vec<BoxRankingRule<'ctx, PlaceholderQuery>>> {
     // query graph search
 
@@ -347,6 +348,7 @@ fn get_ranking_rules_for_vector<'ctx>(
                         limit_plus_offset,
                         embedder_name,
                         embedder,
+                        quantized,
                     )?;
                     ranking_rules.push(Box::new(vector_sort));
                     vector = true;
@@ -576,6 +578,7 @@ pub fn execute_vector_search(
     length: usize,
     embedder_name: &str,
     embedder: &Embedder,
+    quantized: bool,
     time_budget: TimeBudget,
     ranking_score_threshold: Option<f64>,
 ) -> Result<PartialSearchResult> {
@@ -591,6 +594,7 @@ pub fn execute_vector_search(
         vector,
         embedder_name,
         embedder,
+        quantized,
     )?;
 
     let mut placeholder_search_logger = logger::DefaultSearchLogger;

milli/src/search/new/vector_sort.rs

@@ -16,6 +16,7 @@ pub struct VectorSort<Q: RankingRuleQueryTrait> {
     limit: usize,
     distribution_shift: Option<DistributionShift>,
     embedder_index: u8,
+    quantized: bool,
 }
 
 impl<Q: RankingRuleQueryTrait> VectorSort<Q> {
@@ -26,6 +27,7 @@ impl<Q: RankingRuleQueryTrait> VectorSort<Q> {
         limit: usize,
         embedder_name: &str,
         embedder: &Embedder,
+        quantized: bool,
     ) -> Result<Self> {
         let embedder_index = ctx
             .index
@@ -41,6 +43,7 @@ impl<Q: RankingRuleQueryTrait> VectorSort<Q> {
             limit,
             distribution_shift: embedder.distribution(),
             embedder_index,
+            quantized,
         })
     }
 
@@ -49,16 +52,15 @@ impl<Q: RankingRuleQueryTrait> VectorSort<Q> {
         ctx: &mut SearchContext<'_>,
         vector_candidates: &RoaringBitmap,
     ) -> Result<()> {
-        let readers: std::result::Result<Vec<_>, _> =
+        let readers: Vec<_> =
-            ctx.index.arroy_readers(ctx.txn, self.embedder_index).collect();
+            ctx.index.arroy_readers(self.embedder_index, self.quantized).collect();
-        let readers = readers?;
 
         let target = &self.target;
         let mut results = Vec::new();
 
         for reader in readers.iter() {
             let nns_by_vector =
-                reader.nns_by_vector(ctx.txn, target, self.limit, None, Some(vector_candidates))?;
+                reader.nns_by_vector(ctx.txn, target, self.limit, Some(vector_candidates))?;
             results.extend(nns_by_vector.into_iter());
         }
         results.sort_unstable_by_key(|(_, distance)| OrderedFloat(*distance));

milli/src/search/similar.rs

@@ -18,6 +18,7 @@ pub struct Similar<'a> {
     embedder_name: String,
     embedder: Arc<Embedder>,
     ranking_score_threshold: Option<f64>,
+    quantized: bool,
 }
 
 impl<'a> Similar<'a> {
@@ -29,6 +30,7 @@ impl<'a> Similar<'a> {
         rtxn: &'a heed::RoTxn<'a>,
         embedder_name: String,
         embedder: Arc<Embedder>,
+        quantized: bool,
     ) -> Self {
         Self {
             id,
@@ -40,6 +42,7 @@ impl<'a> Similar<'a> {
             embedder_name,
             embedder,
             ranking_score_threshold: None,
+            quantized,
         }
     }
 
@@ -67,10 +70,7 @@ impl<'a> Similar<'a> {
                 .get(self.rtxn, &self.embedder_name)?
                 .ok_or_else(|| crate::UserError::InvalidEmbedder(self.embedder_name.to_owned()))?;
 
-        let readers: std::result::Result<Vec<_>, _> =
+        let readers: Vec<_> = self.index.arroy_readers(embedder_index, self.quantized).collect();
-            self.index.arroy_readers(self.rtxn, embedder_index).collect();
-
-        let readers = readers?;
 
         let mut results = Vec::new();
 
@@ -79,7 +79,6 @@ impl<'a> Similar<'a> {
                 self.rtxn,
                 self.id,
                 self.limit + self.offset + 1,
-                None,
                 Some(&universe),
             )?;
             if let Some(mut nns_by_item) = nns_by_item {

milli/src/update/index_documents/extract/extract_vector_points.rs

@@ -20,7 +20,7 @@ use crate::update::del_add::{DelAdd, KvReaderDelAdd, KvWriterDelAdd};
 use crate::update::settings::InnerIndexSettingsDiff;
 use crate::vector::error::{EmbedErrorKind, PossibleEmbeddingMistakes, UnusedVectorsDistribution};
 use crate::vector::parsed_vectors::{ParsedVectorsDiff, VectorState, RESERVED_VECTORS_FIELD_NAME};
-use crate::vector::settings::{EmbedderAction, ReindexAction};
+use crate::vector::settings::ReindexAction;
 use crate::vector::{Embedder, Embeddings};
 use crate::{try_split_array_at, DocumentId, FieldId, Result, ThreadPoolNoAbort};
 
@@ -208,65 +208,65 @@ pub fn extract_vector_points<R: io::Read + io::Seek>(
 
     if reindex_vectors {
         for (name, action) in settings_diff.embedding_config_updates.iter() {
-            match action {
+            if let Some(action) = action.reindex() {
-                EmbedderAction::WriteBackToDocuments(_) => continue, // already deleted
+                let Some((embedder_name, (embedder, prompt, _quantized))) =
-                EmbedderAction::Reindex(action) => {
+                    configs.remove_entry(name)
-                    let Some((embedder_name, (embedder, prompt))) = configs.remove_entry(name)
+                else {
-                    else {
+                    tracing::error!(embedder = name, "Requested embedder config not found");
-                        tracing::error!(embedder = name, "Requested embedder config not found");
+                    continue;
-                        continue;
+                };
-                    };
 
-                    // (docid, _index) -> KvWriterDelAdd -> Vector
+                // (docid, _index) -> KvWriterDelAdd -> Vector
-                    let manual_vectors_writer = create_writer(
+                let manual_vectors_writer = create_writer(
-                        indexer.chunk_compression_type,
+                    indexer.chunk_compression_type,
-                        indexer.chunk_compression_level,
+                    indexer.chunk_compression_level,
-                        tempfile::tempfile()?,
+                    tempfile::tempfile()?,
-                    );
+                );
 
-                    // (docid) -> (prompt)
+                // (docid) -> (prompt)
-                    let prompts_writer = create_writer(
+                let prompts_writer = create_writer(
-                        indexer.chunk_compression_type,
+                    indexer.chunk_compression_type,
-                        indexer.chunk_compression_level,
+                    indexer.chunk_compression_level,
-                        tempfile::tempfile()?,
+                    tempfile::tempfile()?,
-                    );
+                );
 
-                    // (docid) -> ()
+                // (docid) -> ()
-                    let remove_vectors_writer = create_writer(
+                let remove_vectors_writer = create_writer(
-                        indexer.chunk_compression_type,
+                    indexer.chunk_compression_type,
-                        indexer.chunk_compression_level,
+                    indexer.chunk_compression_level,
-                        tempfile::tempfile()?,
+                    tempfile::tempfile()?,
-                    );
+                );
 
-                    let action = match action {
+                let action = match action {
-                        ReindexAction::FullReindex => ExtractionAction::SettingsFullReindex,
+                    ReindexAction::FullReindex => ExtractionAction::SettingsFullReindex,
-                        ReindexAction::RegeneratePrompts => {
+                    ReindexAction::RegeneratePrompts => {
-                            let Some((_, old_prompt)) = old_configs.get(name) else {
+                        let Some((_, old_prompt, _quantized)) = old_configs.get(name) else {
-                                tracing::error!(embedder = name, "Old embedder config not found");
+                            tracing::error!(embedder = name, "Old embedder config not found");
-                                continue;
+                            continue;
-                            };
+                        };
 
-                            ExtractionAction::SettingsRegeneratePrompts { old_prompt }
+                        ExtractionAction::SettingsRegeneratePrompts { old_prompt }
-                        }
+                    }
-                    };
+                };
 
-                    extractors.push(EmbedderVectorExtractor {
+                extractors.push(EmbedderVectorExtractor {
-                        embedder_name,
+                    embedder_name,
-                        embedder,
+                    embedder,
-                        prompt,
+                    prompt,
-                        prompts_writer,
+                    prompts_writer,
-                        remove_vectors_writer,
+                    remove_vectors_writer,
-                        manual_vectors_writer,
+                    manual_vectors_writer,
-                        add_to_user_provided: RoaringBitmap::new(),
+                    add_to_user_provided: RoaringBitmap::new(),
-                        action,
+                    action,
-                    });
+                });
-                }
+            } else {
+                continue;
             }
         }
     } else {
         // document operation
 
-        for (embedder_name, (embedder, prompt)) in configs.into_iter() {
+        for (embedder_name, (embedder, prompt, _quantized)) in configs.into_iter() {
             // (docid, _index) -> KvWriterDelAdd -> Vector
             let manual_vectors_writer = create_writer(
                 indexer.chunk_compression_type,

milli/src/update/index_documents/mod.rs

@@ -43,7 +43,7 @@ use crate::update::index_documents::parallel::ImmutableObkvs;
 use crate::update::{
     IndexerConfig, UpdateIndexingStep, WordPrefixDocids, WordPrefixIntegerDocids, WordsPrefixesFst,
 };
-use crate::vector::EmbeddingConfigs;
+use crate::vector::{ArroyReader, EmbeddingConfigs};
 use crate::{CboRoaringBitmapCodec, Index, Object, Result};
 
 static MERGED_DATABASE_COUNT: usize = 7;
@@ -679,6 +679,24 @@ where
         let number_of_documents = self.index.number_of_documents(self.wtxn)?;
         let mut rng = rand::rngs::StdRng::seed_from_u64(42);
 
+        // If an embedder wasn't used in the typedchunk but must be binary quantized
+        // we should insert it in `dimension`
+        for (name, action) in settings_diff.embedding_config_updates.iter() {
+            if action.is_being_quantized && !dimension.contains_key(name.as_str()) {
+                let index = self.index.embedder_category_id.get(self.wtxn, name)?.ok_or(
+                    InternalError::DatabaseMissingEntry {
+                        db_name: "embedder_category_id",
+                        key: None,
+                    },
+                )?;
+                let first_id = crate::vector::arroy_db_range_for_embedder(index).next().unwrap();
+                let reader =
+                    ArroyReader::new(self.index.vector_arroy, first_id, action.was_quantized);
+                let dim = reader.dimensions(self.wtxn)?;
+                dimension.insert(name.to_string(), dim);
+            }
+        }
+
         for (embedder_name, dimension) in dimension {
             let wtxn = &mut *self.wtxn;
             let vector_arroy = self.index.vector_arroy;
@@ -686,13 +704,19 @@ where
             let embedder_index = self.index.embedder_category_id.get(wtxn, &embedder_name)?.ok_or(
                 InternalError::DatabaseMissingEntry { db_name: "embedder_category_id", key: None },
             )?;
+            let embedder_config = settings_diff.embedding_config_updates.get(&embedder_name);
+            let was_quantized = embedder_config.map_or(false, |action| action.was_quantized);
+            let is_quantizing = embedder_config.map_or(false, |action| action.is_being_quantized);
 
             pool.install(|| {
                 for k in crate::vector::arroy_db_range_for_embedder(embedder_index) {
-                    let writer = arroy::Writer::new(vector_arroy, k, dimension);
+                    let mut writer = ArroyReader::new(vector_arroy, k, was_quantized);
-                    if writer.need_build(wtxn)? {
+                    if is_quantizing {
-                        writer.build(wtxn, &mut rng, None)?;
+                        writer.quantize(wtxn, k, dimension)?;
-                    } else if writer.is_empty(wtxn)? {
+                    }
+                    if writer.need_build(wtxn, dimension)? {
+                        writer.build(wtxn, &mut rng, dimension)?;
+                    } else if writer.is_empty(wtxn, dimension)? {
                         break;
                     }
                 }
@@ -2746,6 +2770,7 @@ mod tests {
                         response: Setting::NotSet,
                         distribution: Setting::NotSet,
                         headers: Setting::NotSet,
+                        binary_quantized: Setting::NotSet,
                     }),
                 );
                 settings.set_embedder_settings(embedders);
@@ -2774,7 +2799,7 @@ mod tests {
             std::sync::Arc::new(crate::vector::Embedder::new(embedder.embedder_options).unwrap());
         let res = index
             .search(&rtxn)
-            .semantic(embedder_name, embedder, Some([0.0, 1.0, 2.0].to_vec()))
+            .semantic(embedder_name, embedder, false, Some([0.0, 1.0, 2.0].to_vec()))
             .execute()
             .unwrap();
         assert_eq!(res.documents_ids.len(), 3);

milli/src/update/index_documents/transform.rs

@@ -28,7 +28,8 @@ use crate::update::index_documents::GrenadParameters;
 use crate::update::settings::{InnerIndexSettings, InnerIndexSettingsDiff};
 use crate::update::{AvailableDocumentsIds, UpdateIndexingStep};
 use crate::vector::parsed_vectors::{ExplicitVectors, VectorOrArrayOfVectors};
-use crate::vector::settings::{EmbedderAction, WriteBackToDocuments};
+use crate::vector::settings::WriteBackToDocuments;
+use crate::vector::ArroyReader;
 use crate::{
     is_faceted_by, FieldDistribution, FieldId, FieldIdMapMissingEntry, FieldsIdsMap, Index, Result,
 };
@@ -989,23 +990,16 @@ impl<'a, 'i> Transform<'a, 'i> {
             None
         };
 
-        let readers: Result<
+        let readers: Result<BTreeMap<&str, (Vec<ArroyReader>, &RoaringBitmap)>> = settings_diff
-            BTreeMap<&str, (Vec<arroy::Reader<'_, arroy::distances::Angular>>, &RoaringBitmap)>,
-        > = settings_diff
             .embedding_config_updates
             .iter()
             .filter_map(|(name, action)| {
-                if let EmbedderAction::WriteBackToDocuments(WriteBackToDocuments {
+                if let Some(WriteBackToDocuments { embedder_id, user_provided }) =
-                    embedder_id,
+                    action.write_back()
-                    user_provided,
-                }) = action
                 {
-                    let readers: Result<Vec<_>> =
+                    let readers: Vec<_> =
-                        self.index.arroy_readers(wtxn, *embedder_id).collect();
+                        self.index.arroy_readers(*embedder_id, action.was_quantized).collect();
-                    match readers {
+                    Some(Ok((name.as_str(), (readers, user_provided))))
-                        Ok(readers) => Some(Ok((name.as_str(), (readers, user_provided)))),
-                        Err(error) => Some(Err(error)),
-                    }
                 } else {
                     None
                 }
@@ -1104,23 +1098,14 @@ impl<'a, 'i> Transform<'a, 'i> {
             }
         }
 
-        let mut writers = Vec::new();
-
         // delete all vectors from the embedders that need removal
         for (_, (readers, _)) in readers {
             for reader in readers {
-                let dimensions = reader.dimensions();
+                let dimensions = reader.dimensions(wtxn)?;
-                let arroy_index = reader.index();
+                reader.clear(wtxn, dimensions)?;
-                drop(reader);
-                let writer = arroy::Writer::new(self.index.vector_arroy, arroy_index, dimensions);
-                writers.push(writer);
             }
         }
 
-        for writer in writers {
-            writer.clear(wtxn)?;
-        }
-
         let grenad_params = GrenadParameters {
             chunk_compression_type: self.indexer_settings.chunk_compression_type,
             chunk_compression_level: self.indexer_settings.chunk_compression_level,

milli/src/update/index_documents/typed_chunk.rs

@@ -27,6 +27,7 @@ use crate::update::index_documents::helpers::{
     as_cloneable_grenad, keep_latest_obkv, try_split_array_at,
 };
 use crate::update::settings::InnerIndexSettingsDiff;
+use crate::vector::ArroyReader;
 use crate::{
     lat_lng_to_xyz, CboRoaringBitmapCodec, DocumentId, FieldId, GeoPoint, Index, InternalError,
     Result, SerializationError, U8StrStrCodec,
@@ -666,9 +667,13 @@ pub(crate) fn write_typed_chunk_into_index(
             let embedder_index = index.embedder_category_id.get(wtxn, &embedder_name)?.ok_or(
                 InternalError::DatabaseMissingEntry { db_name: "embedder_category_id", key: None },
             )?;
+            let binary_quantized = settings_diff
+                .embedding_config_updates
+                .get(&embedder_name)
+                .map_or(false, |conf| conf.was_quantized);
             // FIXME: allow customizing distance
             let writers: Vec<_> = crate::vector::arroy_db_range_for_embedder(embedder_index)
-                .map(|k| arroy::Writer::new(index.vector_arroy, k, expected_dimension))
+                .map(|k| ArroyReader::new(index.vector_arroy, k, binary_quantized))
                 .collect();
 
             // remove vectors for docids we want them removed
@@ -679,7 +684,7 @@ pub(crate) fn write_typed_chunk_into_index(
 
                 for writer in &writers {
                     // Uses invariant: vectors are packed in the first writers.
-                    if !writer.del_item(wtxn, docid)? {
+                    if !writer.del_item(wtxn, expected_dimension, docid)? {
                         break;
                     }
                 }
@@ -711,7 +716,7 @@ pub(crate) fn write_typed_chunk_into_index(
                     )));
                 }
                 for (embedding, writer) in embeddings.iter().zip(&writers) {
-                    writer.add_item(wtxn, docid, embedding)?;
+                    writer.add_item(wtxn, expected_dimension, docid, embedding)?;
                 }
             }
 
@@ -734,7 +739,7 @@ pub(crate) fn write_typed_chunk_into_index(
                             break;
                         };
                         if candidate == vector {
-                            writer.del_item(wtxn, docid)?;
+                            writer.del_item(wtxn, expected_dimension, docid)?;
                             deleted_index = Some(index);
                         }
                     }
@@ -751,8 +756,13 @@ pub(crate) fn write_typed_chunk_into_index(
                         if let Some((last_index, vector)) = last_index_with_a_vector {
                             // unwrap: computed the index from the list of writers
                             let writer = writers.get(last_index).unwrap();
-                            writer.del_item(wtxn, docid)?;
+                            writer.del_item(wtxn, expected_dimension, docid)?;
-                            writers.get(deleted_index).unwrap().add_item(wtxn, docid, &vector)?;
+                            writers.get(deleted_index).unwrap().add_item(
+                                wtxn,
+                                expected_dimension,
+                                docid,
+                                &vector,
+                            )?;
                         }
                     }
                 }
@@ -762,8 +772,8 @@ pub(crate) fn write_typed_chunk_into_index(
 
                     // overflow was detected during vector extraction.
                     for writer in &writers {
-                        if !writer.contains_item(wtxn, docid)? {
+                        if !writer.contains_item(wtxn, expected_dimension, docid)? {
-                            writer.add_item(wtxn, docid, &vector)?;
+                            writer.add_item(wtxn, expected_dimension, docid, &vector)?;
                             break;
                         }
                     }

milli/src/update/settings.rs

@@ -425,11 +425,13 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
         FP: Fn(UpdateIndexingStep) + Sync,
         FA: Fn() -> bool + Sync,
     {
+        println!("inside reindex");
         // if the settings are set before any document update, we don't need to do anything, and
         // will set the primary key during the first document addition.
         if self.index.number_of_documents(self.wtxn)? == 0 {
             return Ok(());
         }
+        println!("didnt early exit");
 
         let transform = Transform::new(
             self.wtxn,
@@ -954,7 +956,7 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                 let old_configs = self.index.embedding_configs(self.wtxn)?;
                 let remove_all: Result<BTreeMap<String, EmbedderAction>> = old_configs
                     .into_iter()
-                    .map(|IndexEmbeddingConfig { name, config: _, user_provided }| -> Result<_> {
+                    .map(|IndexEmbeddingConfig { name, config, user_provided }| -> Result<_> {
                         let embedder_id =
                             self.index.embedder_category_id.get(self.wtxn, &name)?.ok_or(
                                 crate::InternalError::DatabaseMissingEntry {
@@ -964,10 +966,10 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                             )?;
                         Ok((
                             name,
-                            EmbedderAction::WriteBackToDocuments(WriteBackToDocuments {
+                            EmbedderAction::with_write_back(
-                                embedder_id,
+                                WriteBackToDocuments { embedder_id, user_provided },
-                                user_provided,
+                                config.quantized(),
-                            }),
+                            ),
                         ))
                     })
                     .collect();
@@ -1004,7 +1006,8 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
             match joined {
                 // updated config
                 EitherOrBoth::Both((name, (old, user_provided)), (_, new)) => {
-                    let settings_diff = SettingsDiff::from_settings(old, new);
+                    let was_quantized = old.binary_quantized.set().unwrap_or_default();
+                    let settings_diff = SettingsDiff::from_settings(old, new)?;
                     match settings_diff {
                         SettingsDiff::Remove => {
                             tracing::debug!(
@@ -1023,25 +1026,29 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                             self.index.embedder_category_id.delete(self.wtxn, &name)?;
                             embedder_actions.insert(
                                 name,
-                                EmbedderAction::WriteBackToDocuments(WriteBackToDocuments {
+                                EmbedderAction::with_write_back(
-                                    embedder_id,
+                                    WriteBackToDocuments { embedder_id, user_provided },
-                                    user_provided,
+                                    was_quantized,
-                                }),
+                                ),
                             );
                         }
-                        SettingsDiff::Reindex { action, updated_settings } => {
+                        SettingsDiff::Reindex { action, updated_settings, quantize } => {
                             tracing::debug!(
                                 embedder = name,
                                 user_provided = user_provided.len(),
                                 ?action,
                                 "reindex embedder"
                             );
-                            embedder_actions.insert(name.clone(), EmbedderAction::Reindex(action));
+                            embedder_actions.insert(
+                                name.clone(),
+                                EmbedderAction::with_reindex(action, was_quantized)
+                                    .with_is_being_quantized(quantize),
+                            );
                             let new =
                                 validate_embedding_settings(Setting::Set(updated_settings), &name)?;
                             updated_configs.insert(name, (new, user_provided));
                         }
-                        SettingsDiff::UpdateWithoutReindex { updated_settings } => {
+                        SettingsDiff::UpdateWithoutReindex { updated_settings, quantize } => {
                             tracing::debug!(
                                 embedder = name,
                                 user_provided = user_provided.len(),
@@ -1049,6 +1056,12 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                             );
                             let new =
                                 validate_embedding_settings(Setting::Set(updated_settings), &name)?;
+                            if quantize {
+                                embedder_actions.insert(
+                                    name.clone(),
+                                    EmbedderAction::default().with_is_being_quantized(true),
+                                );
+                            }
                             updated_configs.insert(name, (new, user_provided));
                         }
                     }
@@ -1067,8 +1080,10 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                         &mut setting,
                     );
                     let setting = validate_embedding_settings(setting, &name)?;
-                    embedder_actions
+                    embedder_actions.insert(
-                        .insert(name.clone(), EmbedderAction::Reindex(ReindexAction::FullReindex));
+                        name.clone(),
+                        EmbedderAction::with_reindex(ReindexAction::FullReindex, false),
+                    );
                     updated_configs.insert(name, (setting, RoaringBitmap::new()));
                 }
             }
@@ -1082,19 +1097,13 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
         let mut find_free_index =
             move || free_indices.find(|(_, free)| **free).map(|(index, _)| index as u8);
         for (name, action) in embedder_actions.iter() {
-            match action {
+            if matches!(action.reindex(), Some(ReindexAction::FullReindex))
-                EmbedderAction::Reindex(ReindexAction::RegeneratePrompts) => {
+                && self.index.embedder_category_id.get(self.wtxn, name)?.is_none()
-                    /* cannot be a new embedder, so has to have an id already */
+            {
-                }
+                let id =
-                EmbedderAction::Reindex(ReindexAction::FullReindex) => {
+                    find_free_index().ok_or(UserError::TooManyEmbedders(updated_configs.len()))?;
-                    if self.index.embedder_category_id.get(self.wtxn, name)?.is_none() {
+                tracing::debug!(embedder = name, id, "assigning free id to new embedder");
-                        let id = find_free_index()
+                self.index.embedder_category_id.put(self.wtxn, name, &id)?;
-                            .ok_or(UserError::TooManyEmbedders(updated_configs.len()))?;
-                        tracing::debug!(embedder = name, id, "assigning free id to new embedder");
-                        self.index.embedder_category_id.put(self.wtxn, name, &id)?;
-                    }
-                }
-                EmbedderAction::WriteBackToDocuments(_) => { /* already removed */ }
             }
         }
         let updated_configs: Vec<IndexEmbeddingConfig> = updated_configs
@@ -1277,7 +1286,11 @@ impl InnerIndexSettingsDiff {
 
         // if the user-defined searchables changed, then we need to reindex prompts.
         if cache_user_defined_searchables {
-            for (embedder_name, (config, _)) in new_settings.embedding_configs.inner_as_ref() {
+            for (embedder_name, (config, _, _quantized)) in
+                new_settings.embedding_configs.inner_as_ref()
+            {
+                let was_quantized =
+                    old_settings.embedding_configs.get(&embedder_name).map_or(false, |conf| conf.2);
                 // skip embedders that don't use document templates
                 if !config.uses_document_template() {
                     continue;
@@ -1287,16 +1300,19 @@ impl InnerIndexSettingsDiff {
                 // this always makes the code clearer by explicitly handling the cases
                 match embedding_config_updates.entry(embedder_name.clone()) {
                     std::collections::btree_map::Entry::Vacant(entry) => {
-                        entry.insert(EmbedderAction::Reindex(ReindexAction::RegeneratePrompts));
+                        entry.insert(EmbedderAction::with_reindex(
+                            ReindexAction::RegeneratePrompts,
+                            was_quantized,
+                        ));
+                    }
+                    std::collections::btree_map::Entry::Occupied(entry) => {
+                        let EmbedderAction {
+                            was_quantized: _,
+                            is_being_quantized: _, // We are deleting this embedder, so no point in regeneration
+                            write_back: _,         // We are already fully reindexing
+                            reindex: _,            // We are already regenerating prompts
+                        } = entry.get();
                     }
-                    std::collections::btree_map::Entry::Occupied(entry) => match entry.get() {
-                        EmbedderAction::WriteBackToDocuments(_) => { /* we are deleting this embedder, so no point in regeneration */
-                        }
-                        EmbedderAction::Reindex(ReindexAction::FullReindex) => { /* we are already fully reindexing */
-                        }
-                        EmbedderAction::Reindex(ReindexAction::RegeneratePrompts) => { /* we are already regenerating prompts */
-                        }
-                    },
                 };
             }
         }
@@ -1546,7 +1562,7 @@ fn embedders(embedding_configs: Vec<IndexEmbeddingConfig>) -> Result<EmbeddingCo
         .map(
             |IndexEmbeddingConfig {
                  name,
-                 config: EmbeddingConfig { embedder_options, prompt },
+                 config: EmbeddingConfig { embedder_options, prompt, quantized },
                  ..
              }| {
                 let prompt = Arc::new(prompt.try_into().map_err(crate::Error::from)?);
@@ -1556,7 +1572,7 @@ fn embedders(embedding_configs: Vec<IndexEmbeddingConfig>) -> Result<EmbeddingCo
                         .map_err(crate::vector::Error::from)
                         .map_err(crate::Error::from)?,
                 );
-                Ok((name, (embedder, prompt)))
+                Ok((name, (embedder, prompt, quantized.unwrap_or_default())))
             },
         )
         .collect();
@@ -1581,6 +1597,7 @@ fn validate_prompt(
             response,
             distribution,
             headers,
+            binary_quantized: binary_quantize,
         }) => {
             let max_bytes = match document_template_max_bytes.set() {
                 Some(max_bytes) => NonZeroUsize::new(max_bytes).ok_or_else(|| {
@@ -1613,6 +1630,7 @@ fn validate_prompt(
                 response,
                 distribution,
                 headers,
+                binary_quantized: binary_quantize,
             }))
         }
         new => Ok(new),
@@ -1638,6 +1656,7 @@ pub fn validate_embedding_settings(
         response,
         distribution,
         headers,
+        binary_quantized: binary_quantize,
     } = settings;
 
     if let Some(0) = dimensions.set() {
@@ -1678,6 +1697,7 @@ pub fn validate_embedding_settings(
             response,
             distribution,
             headers,
+            binary_quantized: binary_quantize,
         }));
     };
     match inferred_source {
@@ -1779,6 +1799,7 @@ pub fn validate_embedding_settings(
         response,
         distribution,
         headers,
+        binary_quantized: binary_quantize,
     }))
 }
 

milli/src/vector/mod.rs

@@ -1,8 +1,12 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 
+use arroy::distances::{Angular, BinaryQuantizedAngular};
+use arroy::ItemId;
 use deserr::{DeserializeError, Deserr};
+use heed::{RoTxn, RwTxn, Unspecified};
 use ordered_float::OrderedFloat;
+use roaring::RoaringBitmap;
 use serde::{Deserialize, Serialize};
 
 use self::error::{EmbedError, NewEmbedderError};
@@ -26,6 +30,171 @@ pub type Embedding = Vec<f32>;
 
 pub const REQUEST_PARALLELISM: usize = 40;
 
+pub struct ArroyReader {
+    quantized: bool,
+    index: u16,
+    database: arroy::Database<Unspecified>,
+}
+
+impl ArroyReader {
+    pub fn new(database: arroy::Database<Unspecified>, index: u16, quantized: bool) -> Self {
+        Self { database, index, quantized }
+    }
+
+    pub fn index(&self) -> u16 {
+        self.index
+    }
+
+    pub fn dimensions(&self, rtxn: &RoTxn) -> Result<usize, arroy::Error> {
+        if self.quantized {
+            Ok(arroy::Reader::open(rtxn, self.index, self.quantized_db())?.dimensions())
+        } else {
+            Ok(arroy::Reader::open(rtxn, self.index, self.angular_db())?.dimensions())
+        }
+    }
+
+    pub fn quantize(
+        &mut self,
+        wtxn: &mut RwTxn,
+        index: u16,
+        dimension: usize,
+    ) -> Result<(), arroy::Error> {
+        if !self.quantized {
+            let writer = arroy::Writer::new(self.angular_db(), index, dimension);
+            writer.prepare_changing_distance::<BinaryQuantizedAngular>(wtxn)?;
+            self.quantized = true;
+        }
+        Ok(())
+    }
+
+    pub fn need_build(&self, rtxn: &RoTxn, dimension: usize) -> Result<bool, arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).need_build(rtxn)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).need_build(rtxn)
+        }
+    }
+
+    pub fn build<R: rand::Rng + rand::SeedableRng>(
+        &self,
+        wtxn: &mut RwTxn,
+        rng: &mut R,
+        dimension: usize,
+    ) -> Result<(), arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).build(wtxn, rng, None)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).build(wtxn, rng, None)
+        }
+    }
+
+    pub fn add_item(
+        &self,
+        wtxn: &mut RwTxn,
+        dimension: usize,
+        item_id: arroy::ItemId,
+        vector: &[f32],
+    ) -> Result<(), arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension)
+                .add_item(wtxn, item_id, vector)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension)
+                .add_item(wtxn, item_id, vector)
+        }
+    }
+
+    pub fn del_item(
+        &self,
+        wtxn: &mut RwTxn,
+        dimension: usize,
+        item_id: arroy::ItemId,
+    ) -> Result<bool, arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).del_item(wtxn, item_id)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).del_item(wtxn, item_id)
+        }
+    }
+
+    pub fn clear(&self, wtxn: &mut RwTxn, dimension: usize) -> Result<(), arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).clear(wtxn)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).clear(wtxn)
+        }
+    }
+
+    pub fn is_empty(&self, rtxn: &RoTxn, dimension: usize) -> Result<bool, arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).is_empty(rtxn)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).is_empty(rtxn)
+        }
+    }
+
+    pub fn contains_item(
+        &self,
+        rtxn: &RoTxn,
+        dimension: usize,
+        item: arroy::ItemId,
+    ) -> Result<bool, arroy::Error> {
+        if self.quantized {
+            arroy::Writer::new(self.quantized_db(), self.index, dimension).contains_item(rtxn, item)
+        } else {
+            arroy::Writer::new(self.angular_db(), self.index, dimension).contains_item(rtxn, item)
+        }
+    }
+
+    pub fn nns_by_item(
+        &self,
+        rtxn: &RoTxn,
+        item: ItemId,
+        limit: usize,
+        filter: Option<&RoaringBitmap>,
+    ) -> Result<Option<Vec<(ItemId, f32)>>, arroy::Error> {
+        if self.quantized {
+            arroy::Reader::open(rtxn, self.index, self.quantized_db())?
+                .nns_by_item(rtxn, item, limit, None, None, filter)
+        } else {
+            arroy::Reader::open(rtxn, self.index, self.angular_db())?
+                .nns_by_item(rtxn, item, limit, None, None, filter)
+        }
+    }
+
+    pub fn nns_by_vector(
+        &self,
+        txn: &RoTxn,
+        item: &[f32],
+        limit: usize,
+        filter: Option<&RoaringBitmap>,
+    ) -> Result<Vec<(ItemId, f32)>, arroy::Error> {
+        if self.quantized {
+            arroy::Reader::open(txn, self.index, self.quantized_db())?
+                .nns_by_vector(txn, item, limit, None, None, filter)
+        } else {
+            arroy::Reader::open(txn, self.index, self.angular_db())?
+                .nns_by_vector(txn, item, limit, None, None, filter)
+        }
+    }
+
+    pub fn item_vector(&self, rtxn: &RoTxn, docid: u32) -> Result<Option<Vec<f32>>, arroy::Error> {
+        if self.quantized {
+            arroy::Reader::open(rtxn, self.index, self.quantized_db())?.item_vector(rtxn, docid)
+        } else {
+            arroy::Reader::open(rtxn, self.index, self.angular_db())?.item_vector(rtxn, docid)
+        }
+    }
+
+    fn angular_db(&self) -> arroy::Database<Angular> {
+        self.database.remap_data_type()
+    }
+
+    fn quantized_db(&self) -> arroy::Database<BinaryQuantizedAngular> {
+        self.database.remap_data_type()
+    }
+}
+
 /// One or multiple embeddings stored consecutively in a flat vector.
 pub struct Embeddings<F> {
     data: Vec<F>,
@@ -124,39 +293,48 @@ pub struct EmbeddingConfig {
     pub embedder_options: EmbedderOptions,
     /// Document template
     pub prompt: PromptData,
+    /// If this embedder is binary quantized
+    pub quantized: Option<bool>,
     // TODO: add metrics and anything needed
 }
 
+impl EmbeddingConfig {
+    pub fn quantized(&self) -> bool {
+        self.quantized.unwrap_or_default()
+    }
+}
+
 /// Map of embedder configurations.
 ///
 /// Each configuration is mapped to a name.
 #[derive(Clone, Default)]
-pub struct EmbeddingConfigs(HashMap<String, (Arc<Embedder>, Arc<Prompt>)>);
+pub struct EmbeddingConfigs(HashMap<String, (Arc<Embedder>, Arc<Prompt>, bool)>);
 
 impl EmbeddingConfigs {
     /// Create the map from its internal component.s
-    pub fn new(data: HashMap<String, (Arc<Embedder>, Arc<Prompt>)>) -> Self {
+    pub fn new(data: HashMap<String, (Arc<Embedder>, Arc<Prompt>, bool)>) -> Self {
         Self(data)
     }
 
     /// Get an embedder configuration and template from its name.
-    pub fn get(&self, name: &str) -> Option<(Arc<Embedder>, Arc<Prompt>)> {
+    pub fn get(&self, name: &str) -> Option<(Arc<Embedder>, Arc<Prompt>, bool)> {
         self.0.get(name).cloned()
     }
 
-    pub fn inner_as_ref(&self) -> &HashMap<String, (Arc<Embedder>, Arc<Prompt>)> {
+    pub fn inner_as_ref(&self) -> &HashMap<String, (Arc<Embedder>, Arc<Prompt>, bool)> {
         &self.0
     }
 
-    pub fn into_inner(self) -> HashMap<String, (Arc<Embedder>, Arc<Prompt>)> {
+    pub fn into_inner(self) -> HashMap<String, (Arc<Embedder>, Arc<Prompt>, bool)> {
         self.0
     }
 }
 
 impl IntoIterator for EmbeddingConfigs {
-    type Item = (String, (Arc<Embedder>, Arc<Prompt>));
+    type Item = (String, (Arc<Embedder>, Arc<Prompt>, bool));
 
-    type IntoIter = std::collections::hash_map::IntoIter<String, (Arc<Embedder>, Arc<Prompt>)>;
+    type IntoIter =
+        std::collections::hash_map::IntoIter<String, (Arc<Embedder>, Arc<Prompt>, bool)>;
 
     fn into_iter(self) -> Self::IntoIter {
         self.0.into_iter()

milli/src/vector/settings.rs

@@ -32,6 +32,9 @@ pub struct EmbeddingSettings {
     pub dimensions: Setting<usize>,
     #[serde(default, skip_serializing_if = "Setting::is_not_set")]
     #[deserr(default)]
+    pub binary_quantized: Setting<bool>,
+    #[serde(default, skip_serializing_if = "Setting::is_not_set")]
+    #[deserr(default)]
     pub document_template: Setting<String>,
     #[serde(default, skip_serializing_if = "Setting::is_not_set")]
     #[deserr(default)]
@@ -85,23 +88,62 @@ pub enum ReindexAction {
 
 pub enum SettingsDiff {
     Remove,
-    Reindex { action: ReindexAction, updated_settings: EmbeddingSettings },
+    Reindex { action: ReindexAction, updated_settings: EmbeddingSettings, quantize: bool },
-    UpdateWithoutReindex { updated_settings: EmbeddingSettings },
+    UpdateWithoutReindex { updated_settings: EmbeddingSettings, quantize: bool },
 }
 
-pub enum EmbedderAction {
+#[derive(Default, Debug)]
-    WriteBackToDocuments(WriteBackToDocuments),
+pub struct EmbedderAction {
-    Reindex(ReindexAction),
+    pub was_quantized: bool,
+    pub is_being_quantized: bool,
+    pub write_back: Option<WriteBackToDocuments>,
+    pub reindex: Option<ReindexAction>,
 }
 
+impl EmbedderAction {
+    pub fn is_being_quantized(&self) -> bool {
+        self.is_being_quantized
+    }
+
+    pub fn write_back(&self) -> Option<&WriteBackToDocuments> {
+        self.write_back.as_ref()
+    }
+
+    pub fn reindex(&self) -> Option<&ReindexAction> {
+        self.reindex.as_ref()
+    }
+
+    pub fn with_is_being_quantized(mut self, quantize: bool) -> Self {
+        self.is_being_quantized = quantize;
+        self
+    }
+
+    pub fn with_write_back(write_back: WriteBackToDocuments, was_quantized: bool) -> Self {
+        Self {
+            was_quantized,
+            is_being_quantized: false,
+            write_back: Some(write_back),
+            reindex: None,
+        }
+    }
+
+    pub fn with_reindex(reindex: ReindexAction, was_quantized: bool) -> Self {
+        Self { was_quantized, is_being_quantized: false, write_back: None, reindex: Some(reindex) }
+    }
+}
+
+#[derive(Debug)]
 pub struct WriteBackToDocuments {
     pub embedder_id: u8,
     pub user_provided: RoaringBitmap,
 }
 
 impl SettingsDiff {
-    pub fn from_settings(old: EmbeddingSettings, new: Setting<EmbeddingSettings>) -> Self {
+    pub fn from_settings(
-        match new {
+        old: EmbeddingSettings,
+        new: Setting<EmbeddingSettings>,
+    ) -> Result<Self, UserError> {
+        let ret = match new {
             Setting::Set(new) => {
                 let EmbeddingSettings {
                     mut source,
@@ -116,6 +158,7 @@ impl SettingsDiff {
                     mut distribution,
                     mut headers,
                     mut document_template_max_bytes,
+                    binary_quantized: mut binary_quantize,
                 } = old;
 
                 let EmbeddingSettings {
@@ -131,8 +174,17 @@ impl SettingsDiff {
                     distribution: new_distribution,
                     headers: new_headers,
                     document_template_max_bytes: new_document_template_max_bytes,
+                    binary_quantized: new_binary_quantize,
                 } = new;
 
+                if matches!(binary_quantize, Setting::Set(true))
+                    && matches!(new_binary_quantize, Setting::Set(false))
+                {
+                    return Err(UserError::InvalidDisableBinaryQuantization {
+                        embedder_name: String::from("todo"),
+                    });
+                }
+
                 let mut reindex_action = None;
 
                 // **Warning**: do not use short-circuiting || here, we want all these operations applied
@@ -172,6 +224,7 @@ impl SettingsDiff {
                         _ => {}
                     }
                 }
+                let binary_quantize_changed = binary_quantize.apply(new_binary_quantize);
                 if url.apply(new_url) {
                     match source {
                         // do not regenerate on an url change in OpenAI
@@ -231,16 +284,27 @@ impl SettingsDiff {
                     distribution,
                     headers,
                     document_template_max_bytes,
+                    binary_quantized: binary_quantize,
                 };
 
                 match reindex_action {
-                    Some(action) => Self::Reindex { action, updated_settings },
+                    Some(action) => Self::Reindex {
-                    None => Self::UpdateWithoutReindex { updated_settings },
+                        action,
+                        updated_settings,
+                        quantize: binary_quantize_changed,
+                    },
+                    None => Self::UpdateWithoutReindex {
+                        updated_settings,
+                        quantize: binary_quantize_changed,
+                    },
                 }
             }
             Setting::Reset => Self::Remove,
-            Setting::NotSet => Self::UpdateWithoutReindex { updated_settings: old },
+            Setting::NotSet => {
-        }
+                Self::UpdateWithoutReindex { updated_settings: old, quantize: false }
+            }
+        };
+        Ok(ret)
     }
 }
 
@@ -486,7 +550,7 @@ impl std::fmt::Display for EmbedderSource {
 
 impl From<EmbeddingConfig> for EmbeddingSettings {
     fn from(value: EmbeddingConfig) -> Self {
-        let EmbeddingConfig { embedder_options, prompt } = value;
+        let EmbeddingConfig { embedder_options, prompt, quantized } = value;
         let document_template_max_bytes =
             Setting::Set(prompt.max_bytes.unwrap_or(default_max_bytes()).get());
         match embedder_options {
@@ -507,6 +571,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 response: Setting::NotSet,
                 headers: Setting::NotSet,
                 distribution: Setting::some_or_not_set(distribution),
+                binary_quantized: Setting::some_or_not_set(quantized),
             },
             super::EmbedderOptions::OpenAi(super::openai::EmbedderOptions {
                 url,
@@ -527,6 +592,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 response: Setting::NotSet,
                 headers: Setting::NotSet,
                 distribution: Setting::some_or_not_set(distribution),
+                binary_quantized: Setting::some_or_not_set(quantized),
             },
             super::EmbedderOptions::Ollama(super::ollama::EmbedderOptions {
                 embedding_model,
@@ -547,6 +613,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 response: Setting::NotSet,
                 headers: Setting::NotSet,
                 distribution: Setting::some_or_not_set(distribution),
+                binary_quantized: Setting::some_or_not_set(quantized),
             },
             super::EmbedderOptions::UserProvided(super::manual::EmbedderOptions {
                 dimensions,
@@ -564,6 +631,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 response: Setting::NotSet,
                 headers: Setting::NotSet,
                 distribution: Setting::some_or_not_set(distribution),
+                binary_quantized: Setting::some_or_not_set(quantized),
             },
             super::EmbedderOptions::Rest(super::rest::EmbedderOptions {
                 api_key,
@@ -586,6 +654,7 @@ impl From<EmbeddingConfig> for EmbeddingSettings {
                 response: Setting::Set(response),
                 distribution: Setting::some_or_not_set(distribution),
                 headers: Setting::Set(headers),
+                binary_quantized: Setting::some_or_not_set(quantized),
             },
         }
     }
@@ -607,8 +676,11 @@ impl From<EmbeddingSettings> for EmbeddingConfig {
             response,
             distribution,
             headers,
+            binary_quantized,
         } = value;
 
+        this.quantized = binary_quantized.set();
+
         if let Some(source) = source.set() {
             match source {
                 EmbedderSource::OpenAi => {