WIP

Cargo.lock

@@ -383,7 +383,7 @@ dependencies = [
 [[package]]
 name = "arroy"
 version = "0.1.0"
-source = "git+https://github.com/meilisearch/arroy.git#4b59476f457e5443ff250ea10d40d8b66a692674"
+source = "git+https://github.com/meilisearch/arroy.git#0079af0ec960bc9c51dd66e898a6b5e980cbb083"
 dependencies = [
  "bytemuck",
  "byteorder",

milli/src/error.rs

@@ -61,6 +61,8 @@ pub enum InternalError {
     AbortedIndexation,
     #[error("The matching words list contains at least one invalid member.")]
     InvalidMatchingWords,
+    #[error(transparent)]
+    ArroyError(#[from] arroy::Error),
 }
 
 #[derive(Error, Debug)]
@@ -190,6 +192,24 @@ only composed of alphanumeric characters (a-z A-Z 0-9), hyphens (-) and undersco
     InvalidPromptForEmbeddings(String, crate::prompt::error::NewPromptError),
 }
 
+impl From<arroy::Error> for Error {
+    fn from(value: arroy::Error) -> Self {
+        match value {
+            arroy::Error::Heed(heed) => heed.into(),
+            arroy::Error::Io(io) => io.into(),
+            arroy::Error::InvalidVecDimension { expected, received } => {
+                Error::UserError(UserError::InvalidVectorDimensions { expected, found: received })
+            }
+            arroy::Error::DatabaseFull
+            | arroy::Error::InvalidItemAppend
+            | arroy::Error::UnmatchingDistance { .. }
+            | arroy::Error::MissingMetadata => {
+                Error::InternalError(InternalError::ArroyError(value))
+            }
+        }
+    }
+}
+
 #[derive(Error, Debug)]
 pub enum GeoError {
     #[error("The `_geo` field in the document with the id: `{document_id}` is not an object. Was expecting an object with the `_geo.lat` and `_geo.lng` fields but instead got `{value}`.")]

milli/src/index.rs

@@ -70,7 +70,6 @@ pub mod main_key {
     pub const SORT_FACET_VALUES_BY: &str = "sort-facet-values-by";
     pub const PAGINATION_MAX_TOTAL_HITS: &str = "pagination-max-total-hits";
     pub const PROXIMITY_PRECISION: &str = "proximity-precision";
-    pub const VECTOR_UNAVAILABLE_VECTOR_IDS: &str = "vector-unavailable-vector-ids";
     pub const EMBEDDING_CONFIGS: &str = "embedding_configs";
 }
 
@@ -97,8 +96,6 @@ pub mod db_name {
     pub const FACET_ID_STRING_FST: &str = "facet-id-string-fst";
     pub const FIELD_ID_DOCID_FACET_F64S: &str = "field-id-docid-facet-f64s";
     pub const FIELD_ID_DOCID_FACET_STRINGS: &str = "field-id-docid-facet-strings";
-    pub const VECTOR_ID_DOCID: &str = "vector-id-docids";
-    pub const VECTOR_DOCID_IDS: &str = "vector-docid-ids";
     pub const VECTOR_EMBEDDER_CATEGORY_ID: &str = "vector-embedder-category-id";
     pub const VECTOR_ARROY: &str = "vector-arroy";
     pub const DOCUMENTS: &str = "documents";
@@ -167,16 +164,10 @@ pub struct Index {
     /// Maps the document id, the facet field id and the strings.
     pub field_id_docid_facet_strings: Database<FieldDocIdFacetStringCodec, Str>,
 
-    /// Maps a vector id to its document id.
-    pub vector_id_docid: Database<BEU32, BEU32>,
-    /// Maps a doc id to its vector ids.
-    pub docid_vector_ids: Database<BEU32, CboRoaringBitmapCodec>,
-
     /// Maps an embedder name to its id in the arroy store.
-    pub embedder_category_id: Database<Str, BEU16>,
-
+    pub embedder_category_id: Database<Str, U8>,
     /// Vector store based on arroy™.
-    pub vector_arroy: arroy::Database<arroy::distances::DotProduct>,
+    pub vector_arroy: arroy::Database<arroy::distances::Angular>,
 
     /// Maps the document id to the document as an obkv store.
     pub(crate) documents: Database<BEU32, ObkvCodec>,
@@ -191,7 +182,7 @@ impl Index {
     ) -> Result<Index> {
         use db_name::*;
 
-        options.max_dbs(27);
+        options.max_dbs(25);
 
         let env = options.open(path)?;
         let mut wtxn = env.write_txn()?;
@@ -232,8 +223,6 @@ impl Index {
         let field_id_docid_facet_strings =
             env.create_database(&mut wtxn, Some(FIELD_ID_DOCID_FACET_STRINGS))?;
         // vector stuff
-        let vector_id_docid = env.create_database(&mut wtxn, Some(VECTOR_ID_DOCID))?;
-        let docid_vector_ids = env.create_database(&mut wtxn, Some(VECTOR_DOCID_IDS))?;
         let embedder_category_id =
             env.create_database(&mut wtxn, Some(VECTOR_EMBEDDER_CATEGORY_ID))?;
         let vector_arroy = env.create_database(&mut wtxn, Some(VECTOR_ARROY))?;
@@ -267,9 +256,7 @@ impl Index {
             facet_id_is_empty_docids,
             field_id_docid_facet_f64s,
             field_id_docid_facet_strings,
-            vector_id_docid,
             vector_arroy,
-            docid_vector_ids,
             embedder_category_id,
             documents,
         })
@@ -1516,30 +1503,6 @@ impl Index {
             .get(rtxn, main_key::EMBEDDING_CONFIGS)?
             .unwrap_or_default())
     }
-
-    pub(crate) fn put_unavailable_vector_ids(
-        &self,
-        wtxn: &mut RwTxn<'_>,
-        unavailable_vector_ids: RoaringBitmap,
-    ) -> heed::Result<()> {
-        self.main.remap_types::<Str, CboRoaringBitmapCodec>().put(
-            wtxn,
-            main_key::VECTOR_UNAVAILABLE_VECTOR_IDS,
-            &unavailable_vector_ids,
-        )
-    }
-
-    pub(crate) fn delete_unavailable_vector_ids(&self, wtxn: &mut RwTxn<'_>) -> heed::Result<bool> {
-        self.main.remap_key_type::<Str>().delete(wtxn, main_key::VECTOR_UNAVAILABLE_VECTOR_IDS)
-    }
-
-    pub fn unavailable_vector_ids(&self, rtxn: &RoTxn<'_>) -> Result<RoaringBitmap> {
-        Ok(self
-            .main
-            .remap_types::<Str, CboRoaringBitmapCodec>()
-            .get(rtxn, main_key::VECTOR_UNAVAILABLE_VECTOR_IDS)?
-            .unwrap_or_default())
-    }
 }
 
 #[cfg(test)]

milli/src/search/new/mod.rs

@@ -262,6 +262,7 @@ fn get_ranking_rules_for_vector<'ctx>(
     ctx: &SearchContext<'ctx>,
     sort_criteria: &Option<Vec<AscDesc>>,
     geo_strategy: geo_sort::Strategy,
+    limit_plus_offset: usize,
     target: &[f32],
 ) -> Result<Vec<BoxRankingRule<'ctx, PlaceholderQuery>>> {
     // query graph search
@@ -283,7 +284,12 @@ fn get_ranking_rules_for_vector<'ctx>(
             | crate::Criterion::Exactness => {
                 if !vector {
                     let vector_candidates = ctx.index.documents_ids(ctx.txn)?;
-                    let vector_sort = VectorSort::new(ctx, target.to_vec(), vector_candidates)?;
+                    let vector_sort = VectorSort::new(
+                        ctx,
+                        target.to_vec(),
+                        vector_candidates,
+                        limit_plus_offset,
+                    )?;
                     ranking_rules.push(Box::new(vector_sort));
                     vector = true;
                 }
@@ -509,7 +515,8 @@ pub fn execute_vector_search(
 
     /// FIXME: input universe = universe & documents_with_vectors
     // for now if we're computing embeddings for ALL documents, we can assume that this is just universe
-    let ranking_rules = get_ranking_rules_for_vector(ctx, sort_criteria, geo_strategy, vector)?;
+    let ranking_rules =
+        get_ranking_rules_for_vector(ctx, sort_criteria, geo_strategy, from + length, vector)?;
 
     let mut placeholder_search_logger = logger::DefaultSearchLogger;
     let placeholder_search_logger: &mut dyn SearchLogger<PlaceholderQuery> =

milli/src/search/new/vector_sort.rs

@@ -1,48 +1,83 @@
-use std::future::Future;
 use std::iter::FromIterator;
-use std::pin::Pin;
 
-use nolife::DynBoxScope;
+use ordered_float::OrderedFloat;
 use roaring::RoaringBitmap;
 
 use super::ranking_rules::{RankingRule, RankingRuleOutput, RankingRuleQueryTrait};
-use crate::distance::NDotProductPoint;
-use crate::index::Hnsw;
 use crate::score_details::{self, ScoreDetails};
-use crate::{Result, SearchContext, SearchLogger, UserError};
+use crate::{DocumentId, Result, SearchContext, SearchLogger};
 
-pub struct VectorSort<'ctx, Q: RankingRuleQueryTrait> {
+pub struct VectorSort<Q: RankingRuleQueryTrait> {
     query: Option<Q>,
     target: Vec<f32>,
     vector_candidates: RoaringBitmap,
-    reader: arroy::Reader<'ctx, arroy::distances::DotProduct>,
+    cached_sorted_docids: std::vec::IntoIter<(DocumentId, f32, Vec<f32>)>,
     limit: usize,
 }
 
-impl<'ctx, Q: RankingRuleQueryTrait> VectorSort<'ctx, Q> {
+impl<Q: RankingRuleQueryTrait> VectorSort<Q> {
     pub fn new(
-        ctx: &'ctx SearchContext,
+        _ctx: &SearchContext,
         target: Vec<f32>,
         vector_candidates: RoaringBitmap,
         limit: usize,
     ) -> Result<Self> {
-        /// FIXME? what to do in case of missing metadata
-        let reader = arroy::Reader::open(ctx.txn, 0, ctx.index.vector_arroy)?;
+        Ok(Self {
+            query: None,
+            target,
+            vector_candidates,
+            cached_sorted_docids: Default::default(),
+            limit,
+        })
+    }
 
-        let target_clone = target.clone();
+    fn fill_buffer(&mut self, ctx: &mut SearchContext<'_>) -> Result<()> {
+        let readers: std::result::Result<Vec<_>, _> = (0..=u8::MAX)
+            .map_while(|k| {
+                arroy::Reader::open(ctx.txn, k.into(), ctx.index.vector_arroy)
+                    .map(Some)
+                    .or_else(|e| match e {
+                        arroy::Error::MissingMetadata => Ok(None),
+                        e => Err(e),
+                    })
+                    .transpose()
+            })
+            .collect();
 
-        Ok(Self { query: None, target, vector_candidates, reader, limit })
+        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(&self.vector_candidates),
+            )?;
+            let vectors: std::result::Result<Vec<_>, _> = nns_by_vector
+                .iter()
+                .map(|(docid, _)| reader.item_vector(ctx.txn, *docid).transpose().unwrap())
+                .collect();
+            let vectors = vectors?;
+            results.extend(nns_by_vector.into_iter().zip(vectors).map(|((x, y), z)| (x, y, z)));
+        }
+        results.sort_unstable_by_key(|(_, distance, _)| OrderedFloat(*distance));
+        self.cached_sorted_docids = results.into_iter();
+        Ok(())
     }
 }
 
-impl<'ctx, Q: RankingRuleQueryTrait> RankingRule<'ctx, Q> for VectorSort<'ctx, Q> {
+impl<'ctx, Q: RankingRuleQueryTrait> RankingRule<'ctx, Q> for VectorSort<Q> {
     fn id(&self) -> String {
         "vector_sort".to_owned()
     }
 
     fn start_iteration(
         &mut self,
-        _ctx: &mut SearchContext<'ctx>,
+        ctx: &mut SearchContext<'ctx>,
         _logger: &mut dyn SearchLogger<Q>,
         universe: &RoaringBitmap,
         query: &Q,
@@ -51,7 +86,7 @@ impl<'ctx, Q: RankingRuleQueryTrait> RankingRule<'ctx, Q> for VectorSort<'ctx, Q
 
         self.query = Some(query.clone());
         self.vector_candidates &= universe;
-
+        self.fill_buffer(ctx)?;
         Ok(())
     }
 
@@ -75,40 +110,24 @@ impl<'ctx, Q: RankingRuleQueryTrait> RankingRule<'ctx, Q> for VectorSort<'ctx, Q
                 }),
             }));
         }
-        let target = &self.target;
-        let vector_candidates = &self.vector_candidates;
 
-        let result = self.reader.nns_by_vector(ctx.txn, &target, count, search_k, candidates)
-
-        scope.enter(|it| {
-            for item in it.by_ref() {
-                let item: Item = item;
-                let index = item.pid.into_inner();
-                let docid = ctx.index.vector_id_docid.get(ctx.txn, &index)?.unwrap();
-
-                if vector_candidates.contains(docid) {
-                    return Ok(Some(RankingRuleOutput {
-                        query,
-                        candidates: RoaringBitmap::from_iter([docid]),
-                        score: ScoreDetails::Vector(score_details::Vector {
-                            target_vector: target.clone(),
-                            value_similarity: Some((
-                                item.point.clone().into_inner(),
-                                1.0 - item.distance,
-                            )),
-                        }),
-                    }));
-                }
+        while let Some((docid, distance, vector)) = self.cached_sorted_docids.next() {
+            if self.vector_candidates.contains(docid) {
+                return Ok(Some(RankingRuleOutput {
+                    query,
+                    candidates: RoaringBitmap::from_iter([docid]),
+                    score: ScoreDetails::Vector(score_details::Vector {
+                        target_vector: self.target.clone(),
+                        value_similarity: Some((vector, 1.0 - distance)),
+                    }),
+                }));
             }
-            Ok(Some(RankingRuleOutput {
-                query,
-                candidates: universe.clone(),
-                score: ScoreDetails::Vector(score_details::Vector {
-                    target_vector: target.clone(),
-                    value_similarity: None,
-                }),
-            }))
-        })
+        }
+
+        // if we got out of this loop it means we've exhausted our cache.
+        // we need to refill it and run the function again.
+        self.fill_buffer(ctx)?;
+        self.next_bucket(ctx, _logger, universe)
     }
 
     fn end_iteration(&mut self, _ctx: &mut SearchContext<'ctx>, _logger: &mut dyn SearchLogger<Q>) {

milli/src/update/clear_documents.rs

@@ -42,9 +42,7 @@ impl<'t, 'i> ClearDocuments<'t, 'i> {
             facet_id_is_empty_docids,
             field_id_docid_facet_f64s,
             field_id_docid_facet_strings,
-            vector_id_docid,
             vector_arroy,
-            docid_vector_ids,
             embedder_category_id: _,
             documents,
         } = self.index;
@@ -86,8 +84,6 @@ impl<'t, 'i> ClearDocuments<'t, 'i> {
         field_id_docid_facet_strings.clear(self.wtxn)?;
         // vector
         vector_arroy.clear(self.wtxn)?;
-        vector_id_docid.clear(self.wtxn)?;
-        docid_vector_ids.clear(self.wtxn)?;
 
         documents.clear(self.wtxn)?;
 

milli/src/update/index_documents/mod.rs

@@ -418,7 +418,7 @@ where
             }
 
             // needs to be dropped to avoid channel waiting lock.
-            drop(lmdb_writer_sx)
+            drop(lmdb_writer_sx);
         });
 
         let index_is_empty = self.index.number_of_documents(self.wtxn)? == 0;
@@ -435,6 +435,8 @@ where
         let mut word_docids = None;
         let mut exact_word_docids = None;
 
+        let mut dimension = None;
+
         for result in lmdb_writer_rx {
             if (self.should_abort)() {
                 return Err(Error::InternalError(InternalError::AbortedIndexation));
@@ -464,6 +466,20 @@ where
                     word_position_docids = Some(cloneable_chunk);
                     TypedChunk::WordPositionDocids(chunk)
                 }
+                TypedChunk::VectorPoints {
+                    expected_dimension,
+                    remove_vectors,
+                    embeddings,
+                    manual_vectors,
+                } => {
+                    dimension = Some(expected_dimension);
+                    TypedChunk::VectorPoints {
+                        remove_vectors,
+                        embeddings,
+                        expected_dimension,
+                        manual_vectors,
+                    }
+                }
                 otherwise => otherwise,
             };
 
@@ -490,9 +506,6 @@ where
             }
         }
 
-        let writer = arroy::Writer::prepare(self.wtxn, self.index.vector_arroy, 0, 0)?;
-        writer.build(self.wtxn, &mut rand::rngs::StdRng::from_entropy(), None)?;
-
         // We write the field distribution into the main database
         self.index.put_field_distribution(self.wtxn, &field_distribution)?;
 
@@ -500,6 +513,23 @@ where
         self.index.put_primary_key(self.wtxn, &primary_key)?;
         let number_of_documents = self.index.number_of_documents(self.wtxn)?;
 
+        if let Some(dimension) = dimension {
+            let wtxn = &mut *self.wtxn;
+            let vector_arroy = self.index.vector_arroy;
+            pool.install(|| {
+                /// FIXME: do for each embedder
+                let mut rng = rand::rngs::StdRng::from_entropy();
+                for k in 0..=u8::MAX {
+                    let writer = arroy::Writer::prepare(wtxn, vector_arroy, k.into(), dimension)?;
+                    if writer.is_empty(wtxn)? {
+                        break;
+                    }
+                    writer.build(wtxn, &mut rng, None)?;
+                }
+                Result::Ok(())
+            })?;
+        }
+
         self.execute_prefix_databases(
             word_docids,
             exact_word_docids,

milli/src/update/index_documents/typed_chunk.rs

@@ -8,9 +8,7 @@ use charabia::{Language, Script};
 use grenad::MergerBuilder;
 use heed::types::Bytes;
 use heed::{PutFlags, RwTxn};
-use log::error;
 use obkv::{KvReader, KvWriter};
-use ordered_float::OrderedFloat;
 use roaring::RoaringBitmap;
 
 use super::helpers::{
@@ -18,16 +16,12 @@ use super::helpers::{
     valid_lmdb_key, CursorClonableMmap,
 };
 use super::{ClonableMmap, MergeFn};
-use crate::distance::NDotProductPoint;
-use crate::error::UserError;
 use crate::external_documents_ids::{DocumentOperation, DocumentOperationKind};
 use crate::facet::FacetType;
 use crate::index::db_name::DOCUMENTS;
-use crate::index::Hnsw;
 use crate::update::del_add::{deladd_serialize_add_side, DelAdd, KvReaderDelAdd};
 use crate::update::facet::FacetsUpdate;
 use crate::update::index_documents::helpers::{as_cloneable_grenad, try_split_array_at};
-use crate::update::{available_documents_ids, AvailableDocumentsIds};
 use crate::{lat_lng_to_xyz, DocumentId, FieldId, GeoPoint, Index, Result, SerializationError};
 
 pub(crate) enum TypedChunk {
@@ -374,28 +368,28 @@ pub(crate) fn write_typed_chunk_into_index(
                 return Ok((RoaringBitmap::new(), is_merged_database));
             }
 
-            let mut unavailable_vector_ids = index.unavailable_vector_ids(&wtxn)?;
             /// FIXME: allow customizing distance
-            /// FIXME: allow customizing index
-            let writer = arroy::Writer::prepare(wtxn, index.vector_arroy, 0, expected_dimension)?;
+            let writers: std::result::Result<Vec<_>, _> = (0..=u8::MAX)
+                .map(|k| {
+                    /// FIXME: allow customizing index and then do index << 8 + k
+                    arroy::Writer::prepare(wtxn, index.vector_arroy, k.into(), expected_dimension)
+                })
+                .collect();
+            let writers = writers?;
 
             // remove vectors for docids we want them removed
             let mut cursor = remove_vectors.into_cursor()?;
             while let Some((key, _)) = cursor.move_on_next()? {
                 let docid = key.try_into().map(DocumentId::from_be_bytes).unwrap();
 
-                let Some(to_remove_vector_ids) = index.docid_vector_ids.get(&wtxn, &docid)? else {
-                    continue;
-                };
-                unavailable_vector_ids -= to_remove_vector_ids;
-
-                for item in to_remove_vector_ids {
-                    writer.del_item(wtxn, item)?;
+                for writer in &writers {
+                    // Uses invariant: vectors are packed in the first writers.
+                    if !writer.del_item(wtxn, docid)? {
+                        break;
+                    }
                 }
             }
 
-            let mut available_vector_ids =
-                AvailableDocumentsIds::from_documents_ids(&unavailable_vector_ids);
             // add generated embeddings
             if let Some(embeddings) = embeddings {
                 let mut cursor = embeddings.into_cursor()?;
@@ -408,19 +402,10 @@ pub(crate) fn write_typed_chunk_into_index(
                             // code error if we somehow got the wrong dimension
                             .unwrap();
 
-                    let mut new_vector_ids = RoaringBitmap::new();
-                    for embedding in embeddings.iter() {
-                        /// FIXME: error when you get over 9000
-                        let next_vector_id = available_vector_ids.next().unwrap();
-                        unavailable_vector_ids.insert(next_vector_id);
-
-                        new_vector_ids.insert(next_vector_id);
-
-                        index.vector_id_docid.put(wtxn, &next_vector_id, &docid)?;
-
-                        writer.add_item(wtxn, next_vector_id, embedding)?;
+                    /// FIXME: detect overflow
+                    for (embedding, writer) in embeddings.iter().zip(&writers) {
+                        writer.add_item(wtxn, docid, embedding)?;
                     }
-                    index.docid_vector_ids.put(wtxn, &docid, &new_vector_ids)?;
                 }
             }
 
@@ -433,44 +418,52 @@ pub(crate) fn write_typed_chunk_into_index(
 
                 let vector_deladd_obkv = KvReaderDelAdd::new(value);
                 if let Some(value) = vector_deladd_obkv.get(DelAdd::Deletion) {
-                    let vector = pod_collect_to_vec(value);
-                    let Some(mut docid_vector_ids) = index.docid_vector_ids.get(&wtxn, &docid)?
-                    else {
-                        error!("Unable to delete the vector: {:?}", vector);
-                        continue;
-                    };
-                    for item in docid_vector_ids {
-                        /// FIXME: comparing the vectors by equality is inefficient, and dangerous by perfect equality
-                        let candidate = writer.item_vector(&wtxn, item)?.expect("Inconsistent dbs");
-                        if candidate == vector {
-                            writer.del_item(wtxn, item)?;
-                            unavailable_vector_ids.remove(item);
-                            index.vector_id_docid.delete(wtxn, &item)?;
-                            docid_vector_ids.remove(item);
+                    let vector: Vec<f32> = pod_collect_to_vec(value);
+
+                    let mut deleted_index = None;
+                    for (index, writer) in writers.iter().enumerate() {
+                        let Some(candidate) = writer.item_vector(&wtxn, docid)? else {
+                            // uses invariant: vectors are packed in the first writers.
                             break;
+                        };
+                        if candidate == vector {
+                            writer.del_item(wtxn, docid)?;
+                            deleted_index = Some(index);
+                        }
+                    }
+
+                    // 🥲 enforce invariant: vectors are packed in the first writers.
+                    if let Some(deleted_index) = deleted_index {
+                        let mut last_index_with_a_vector = None;
+                        for (index, writer) in writers.iter().enumerate().skip(deleted_index) {
+                            let Some(candidate) = writer.item_vector(&wtxn, docid)? else {
+                                break;
+                            };
+                            last_index_with_a_vector = Some((index, candidate));
+                        }
+                        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)?;
+                            writers.get(deleted_index).unwrap().add_item(wtxn, docid, &vector)?;
                         }
                     }
-                    index.docid_vector_ids.put(wtxn, &docid, &docid_vector_ids)?;
                 }
-                let mut available_vector_ids =
-                    AvailableDocumentsIds::from_documents_ids(&unavailable_vector_ids);
 
                 if let Some(value) = vector_deladd_obkv.get(DelAdd::Addition) {
                     let vector = pod_collect_to_vec(value);
-                    let next_vector_id = available_vector_ids.next().unwrap();
 
-                    writer.add_item(wtxn, next_vector_id, &vector)?;
-                    unavailable_vector_ids.insert(next_vector_id);
-                    index.vector_id_docid.put(wtxn, &next_vector_id, &docid)?;
-                    let mut docid_vector_ids =
-                        index.docid_vector_ids.get(&wtxn, &docid)?.unwrap_or_default();
-                    docid_vector_ids.insert(next_vector_id);
-                    index.docid_vector_ids.put(wtxn, &docid, &docid_vector_ids)?;
+                    /// FIXME: detect overflow
+                    for writer in &writers {
+                        if !writer.contains_item(wtxn, docid)? {
+                            writer.add_item(wtxn, docid, &vector)?;
+                            break;
+                        }
+                    }
                 }
             }
 
-            log::debug!("There are {} entries in the arroy so far", unavailable_vector_ids.len());
-            index.put_unavailable_vector_ids(wtxn, unavailable_vector_ids)?;
+            log::debug!("There are 🤷‍♀️ entries in the arroy so far");
         }
         TypedChunk::ScriptLanguageDocids(sl_map) => {
             for (key, (deletion, addition)) in sl_map {