First compiling version with compressed documents iterators

fuzzers/src/bin/fuzz-indexing.rs

@@ -110,7 +110,7 @@ fn main() {
 
                             // after executing a batch we check if the database is corrupted
                             let res = index.search(&wtxn).execute().unwrap();
-                            index.documents(&wtxn, res.documents_ids).unwrap();
+                            index.compressed_documents(&wtxn, res.documents_ids).unwrap();
                             progression.fetch_add(1, Ordering::Relaxed);
                         }
                         wtxn.abort();

index-scheduler/src/batch.rs

@@ -908,16 +908,23 @@ impl IndexScheduler {
                     let mut index_dumper = dump.create_index(uid, &metadata)?;
 
                     let fields_ids_map = index.fields_ids_map(&rtxn)?;
+                    let dictionary = index.document_compression_dictionary(&rtxn)?;
                     let all_fields: Vec<_> = fields_ids_map.iter().map(|(id, _)| id).collect();
                     let embedding_configs = index.embedding_configs(&rtxn)?;
+                    let mut buffer = Vec::new();
 
                     // 3.1. Dump the documents
-                    for ret in index.all_documents(&rtxn)? {
+                    for ret in index.all_compressed_documents(&rtxn)? {
                         if self.must_stop_processing.get() {
                             return Err(Error::AbortedTask);
                         }
 
-                        let (id, doc) = ret?;
+                        let (id, compressed) = ret?;
+                        let doc = match dictionary {
+                            // TODO manage this unwrap correctly
+                            Some(dict) => compressed.decompress_with(&mut buffer, dict).unwrap(),
+                            None => compressed.as_non_compressed(),
+                        };
 
                         let mut document = milli::obkv_to_json(&all_fields, &fields_ids_map, doc)?;
 

index-scheduler/src/lib.rs

@@ -2468,7 +2468,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -2528,7 +2528,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -2907,7 +2907,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -2958,7 +2958,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -3014,7 +3014,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -3132,7 +3132,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -3187,7 +3187,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -3901,7 +3901,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -3972,7 +3972,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4040,7 +4040,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4101,7 +4101,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4166,7 +4166,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4227,7 +4227,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4310,7 +4310,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4396,7 +4396,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -4475,7 +4475,7 @@ mod tests {
         let field_ids_map = index.fields_ids_map(&rtxn).unwrap();
         let field_ids = field_ids_map.ids().collect::<Vec<_>>();
         let documents = index
-            .all_documents(&rtxn)
+            .all_compressed_documents(&rtxn)
             .unwrap()
             .map(|ret| obkv_to_json(&field_ids, &field_ids_map, ret.unwrap().1).unwrap())
             .collect::<Vec<_>>();
@@ -5139,7 +5139,7 @@ mod tests {
             assert_json_snapshot!(embeddings[&simple_hf_name][0] == lab_embed, @"true");
             assert_json_snapshot!(embeddings[&fakerest_name][0] == beagle_embed, @"true");
 
-            let doc = index.documents(&rtxn, std::iter::once(0)).unwrap()[0].1;
+            let doc = index.compressed_documents(&rtxn, std::iter::once(0)).unwrap()[0].1;
             let fields_ids_map = index.fields_ids_map(&rtxn).unwrap();
             let doc = obkv_to_json(
                 &[
@@ -5216,7 +5216,7 @@ mod tests {
                 // remained beagle
                 assert_json_snapshot!(embeddings[&fakerest_name][0] == beagle_embed, @"true");
 
-                let doc = index.documents(&rtxn, std::iter::once(0)).unwrap()[0].1;
+                let doc = index.compressed_documents(&rtxn, std::iter::once(0)).unwrap()[0].1;
                 let fields_ids_map = index.fields_ids_map(&rtxn).unwrap();
                 let doc = obkv_to_json(
                     &[

meilisearch/src/routes/indexes/documents.rs

@@ -603,44 +603,54 @@ fn some_documents<'a, 't: 'a>(
     retrieve_vectors: RetrieveVectors,
 ) -> Result<impl Iterator<Item = Result<Document, ResponseError>> + 'a, ResponseError> {
     let fields_ids_map = index.fields_ids_map(rtxn)?;
+    let dictionary = index.document_compression_dictionary(rtxn)?;
     let all_fields: Vec<_> = fields_ids_map.iter().map(|(id, _)| id).collect();
     let embedding_configs = index.embedding_configs(rtxn)?;
+    let mut buffer = Vec::new();
 
-    Ok(index.iter_documents(rtxn, doc_ids)?.map(move |ret| {
+    Ok(index.iter_compressed_documents(rtxn, doc_ids)?.map(move |ret| {
-        ret.map_err(ResponseError::from).and_then(|(key, document)| -> Result<_, ResponseError> {
+        ret.map_err(ResponseError::from).and_then(
-            let mut document = milli::obkv_to_json(&all_fields, &fields_ids_map, document)?;
+            |(key, compressed_document)| -> Result<_, ResponseError> {
-            match retrieve_vectors {
+                let document = match dictionary {
-                RetrieveVectors::Ignore => {}
+                    // TODO manage this unwrap correctly
-                RetrieveVectors::Hide => {
+                    Some(dict) => compressed_document.decompress_with(&mut buffer, dict).unwrap(),
-                    document.remove("_vectors");
+                    None => compressed_document.as_non_compressed(),
-                }
+                };
-                RetrieveVectors::Retrieve => {
+                let mut document = milli::obkv_to_json(&all_fields, &fields_ids_map, document)?;
-                    // Clippy is simply wrong
+                match retrieve_vectors {
-                    #[allow(clippy::manual_unwrap_or_default)]
+                    RetrieveVectors::Ignore => {}
-                    let mut vectors = match document.remove("_vectors") {
+                    RetrieveVectors::Hide => {
-                        Some(Value::Object(map)) => map,
+                        document.remove("_vectors");
-                        _ => Default::default(),
+                    }
-                    };
+                    RetrieveVectors::Retrieve => {
-                    for (name, vector) in index.embeddings(rtxn, key)? {
+                        // Clippy is simply wrong
-                        let user_provided = embedding_configs
+                        #[allow(clippy::manual_unwrap_or_default)]
-                            .iter()
+                        let mut vectors = match document.remove("_vectors") {
-                            .find(|conf| conf.name == name)
+                            Some(Value::Object(map)) => map,
-                            .is_some_and(|conf| conf.user_provided.contains(key));
+                            _ => Default::default(),
-                        let embeddings = ExplicitVectors {
+                        };
-                            embeddings: Some(vector.into()),
+                        for (name, vector) in index.embeddings(rtxn, key)? {
-                            regenerate: !user_provided,
+                            let user_provided = embedding_configs
-                        };
+                                .iter()
-                        vectors.insert(
+                                .find(|conf| conf.name == name)
-                            name,
+                                .is_some_and(|conf| conf.user_provided.contains(key));
-                            serde_json::to_value(embeddings).map_err(MeilisearchHttpError::from)?,
+                            let embeddings = ExplicitVectors {
-                        );
+                                embeddings: Some(vector.into()),
+                                regenerate: !user_provided,
+                            };
+                            vectors.insert(
+                                name,
+                                serde_json::to_value(embeddings)
+                                    .map_err(MeilisearchHttpError::from)?,
+                            );
+                        }
+                        document.insert("_vectors".into(), vectors.into());
                     }
-                    document.insert("_vectors".into(), vectors.into());
                 }
-            }
 
-            Ok(document)
+                Ok(document)
-        })
+            },
+        )
     }))
 }
 

meilisearch/src/search.rs

@@ -1123,10 +1123,17 @@ fn make_hits(
     formatter_builder.crop_marker(format.crop_marker);
     formatter_builder.highlight_prefix(format.highlight_pre_tag);
     formatter_builder.highlight_suffix(format.highlight_post_tag);
+    let compression_dictionary = index.document_compression_dictionary(rtxn)?;
+    let mut buffer = Vec::new();
     let mut documents = Vec::new();
     let embedding_configs = index.embedding_configs(rtxn)?;
-    let documents_iter = index.documents(rtxn, documents_ids)?;
+    let documents_iter = index.compressed_documents(rtxn, documents_ids)?;
-    for ((id, obkv), score) in documents_iter.into_iter().zip(document_scores.into_iter()) {
+    for ((id, compressed), score) in documents_iter.into_iter().zip(document_scores.into_iter()) {
+        let obkv = match compression_dictionary {
+            // TODO manage this unwrap correctly
+            Some(dict) => compressed.decompress_with(&mut buffer, dict).unwrap(),
+            None => compressed.as_non_compressed(),
+        };
         // First generate a document with all the displayed fields
         let displayed_document = make_document(&displayed_ids, &fields_ids_map, obkv)?;
 

meilitool/src/main.rs

@@ -280,7 +280,7 @@ fn export_a_dump(
         let all_fields: Vec<_> = fields_ids_map.iter().map(|(id, _)| id).collect();
 
         // 4.1. Dump the documents
-        for ret in index.all_documents(&rtxn)? {
+        for ret in index.all_compressed_documents(&rtxn)? {
             let (_id, doc) = ret?;
             let document = obkv_to_json(&all_fields, &fields_ids_map, doc)?;
             index_dumper.push_document(&document)?;

milli/examples/search.rs

@@ -76,7 +76,7 @@ fn main() -> Result<(), Box<dyn Error>> {
             println!("new: {}us, docids: {:?}", elapsed.as_micros(), docs.documents_ids);
             if print_documents {
                 let documents = index
-                    .documents(&txn, docs.documents_ids.iter().copied())
+                    .compressed_documents(&txn, docs.documents_ids.iter().copied())
                     .unwrap()
                     .into_iter()
                     .map(|(id, obkv)| {
@@ -96,7 +96,7 @@ fn main() -> Result<(), Box<dyn Error>> {
                 }
 
                 let documents = index
-                    .documents(&txn, docs.documents_ids.iter().copied())
+                    .compressed_documents(&txn, docs.documents_ids.iter().copied())
                     .unwrap()
                     .into_iter()
                     .map(|(id, obkv)| {

milli/src/heed_codec/compressed_obkv_codec.rs

@@ -24,6 +24,7 @@ impl heed::BytesEncode<'_> for ObkvCompressedCodec {
 pub struct CompressedKvReaderU16<'a>(&'a [u8]);
 
 impl<'a> CompressedKvReaderU16<'a> {
+    /// Decompresses the KvReader into the buffer using the provided dictionnary.
     pub fn decompress_with<'b>(
         &self,
         buffer: &'b mut Vec<u8>,
@@ -38,6 +39,11 @@ impl<'a> CompressedKvReaderU16<'a> {
         )?;
         Ok(KvReaderU16::new(&buffer[..size]))
     }
+
+    /// Returns the KvReader like it is not compressed. Happends when there is no dictionnary yet.
+    pub fn as_non_compressed(&self) -> KvReaderU16<'a> {
+        KvReaderU16::new(self.0)
+    }
 }
 
 pub struct CompressedKvWriterU16(Vec<u8>);

milli/src/heed_codec/mod.rs

@@ -20,6 +20,9 @@ use thiserror::Error;
 
 pub use self::beu16_str_codec::BEU16StrCodec;
 pub use self::beu32_str_codec::BEU32StrCodec;
+pub use self::compressed_obkv_codec::{
+    CompressedKvReaderU16, CompressedKvWriterU16, ObkvCompressedCodec,
+};
 pub use self::field_id_word_count_codec::FieldIdWordCountCodec;
 pub use self::fst_set_codec::FstSetCodec;
 pub use self::obkv_codec::ObkvCodec;

milli/src/index.rs

@@ -20,7 +20,8 @@ use crate::heed_codec::facet::{
     FieldIdCodec, OrderedF64Codec,
 };
 use crate::heed_codec::{
-    BEU16StrCodec, FstSetCodec, ScriptLanguageCodec, StrBEU16Codec, StrRefCodec,
+    BEU16StrCodec, CompressedKvReaderU16, FstSetCodec, ObkvCompressedCodec, ScriptLanguageCodec,
+    StrBEU16Codec, StrRefCodec,
 };
 use crate::order_by_map::OrderByMap;
 use crate::proximity::ProximityPrecision;
@@ -29,8 +30,8 @@ use crate::vector::{Embedding, EmbeddingConfig};
 use crate::{
     default_criteria, CboRoaringBitmapCodec, Criterion, DocumentId, ExternalDocumentsIds,
     FacetDistribution, FieldDistribution, FieldId, FieldIdMapMissingEntry, FieldIdWordCountCodec,
-    FieldidsWeightsMap, GeoPoint, ObkvCodec, Result, RoaringBitmapCodec, RoaringBitmapLenCodec,
+    FieldidsWeightsMap, GeoPoint, Result, RoaringBitmapCodec, RoaringBitmapLenCodec, Search,
-    Search, U8StrStrCodec, Weight, BEU16, BEU32, BEU64,
+    U8StrStrCodec, Weight, BEU16, BEU32, BEU64,
 };
 
 pub const DEFAULT_MIN_WORD_LEN_ONE_TYPO: u8 = 5;
@@ -73,6 +74,7 @@ pub mod main_key {
     pub const PROXIMITY_PRECISION: &str = "proximity-precision";
     pub const EMBEDDING_CONFIGS: &str = "embedding_configs";
     pub const SEARCH_CUTOFF: &str = "search_cutoff";
+    pub const DOCUMENT_COMPRESSION_DICTIONARY: &str = "document-compression-dictionary";
 }
 
 pub mod db_name {
@@ -172,7 +174,7 @@ pub struct Index {
     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>,
+    pub(crate) documents: Database<BEU32, ObkvCompressedCodec>,
 }
 
 impl Index {
@@ -339,6 +341,29 @@ impl Index {
         self.env.prepare_for_closing()
     }
 
+    /* document compression dictionary */
+
+    /// Writes the dictionnary that will further be used to compress the documents.
+    pub fn put_document_compression_dictionary(
+        &self,
+        wtxn: &mut RwTxn,
+        dictionary: &[u8],
+    ) -> heed::Result<()> {
+        self.main.remap_types::<Str, Bytes>().put(
+            wtxn,
+            main_key::DOCUMENT_COMPRESSION_DICTIONARY,
+            dictionary,
+        )
+    }
+
+    /// Returns the optional dictionnary to be used when reading the OBKV documents.
+    pub fn document_compression_dictionary<'t>(
+        &self,
+        rtxn: &'t RoTxn,
+    ) -> heed::Result<Option<&'t [u8]>> {
+        self.main.remap_types::<Str, Bytes>().get(rtxn, main_key::DOCUMENT_COMPRESSION_DICTIONARY)
+    }
+
     /* documents ids */
 
     /// Writes the documents ids that corresponds to the user-ids-documents-ids FST.
@@ -1261,36 +1286,36 @@ impl Index {
 
     /* documents */
 
-    /// Returns an iterator over the requested documents. The next item will be an error if a document is missing.
+    /// Returns an iterator over the requested compressed documents. The next item will be an error if a document is missing.
-    pub fn iter_documents<'a, 't: 'a>(
+    pub fn iter_compressed_documents<'a, 't: 'a>(
         &'a self,
         rtxn: &'t RoTxn<'t>,
         ids: impl IntoIterator<Item = DocumentId> + 'a,
-    ) -> Result<impl Iterator<Item = Result<(DocumentId, obkv::KvReaderU16<'t>)>> + 'a> {
+    ) -> Result<impl Iterator<Item = Result<(DocumentId, CompressedKvReaderU16<'t>)>> + 'a> {
         Ok(ids.into_iter().map(move |id| {
-            let kv = self
+            let compressed = self
                 .documents
                 .get(rtxn, &id)?
                 .ok_or(UserError::UnknownInternalDocumentId { document_id: id })?;
-            Ok((id, kv))
+            Ok((id, compressed))
         }))
     }
 
     /// Returns a [`Vec`] of the requested documents. Returns an error if a document is missing.
-    pub fn documents<'t>(
+    pub fn compressed_documents<'t>(
         &self,
         rtxn: &'t RoTxn<'t>,
         ids: impl IntoIterator<Item = DocumentId>,
-    ) -> Result<Vec<(DocumentId, obkv::KvReaderU16<'t>)>> {
+    ) -> Result<Vec<(DocumentId, CompressedKvReaderU16<'t>)>> {
-        self.iter_documents(rtxn, ids)?.collect()
+        self.iter_compressed_documents(rtxn, ids)?.collect()
     }
 
     /// Returns an iterator over all the documents in the index.
-    pub fn all_documents<'a, 't: 'a>(
+    pub fn all_compressed_documents<'a, 't: 'a>(
         &'a self,
         rtxn: &'t RoTxn<'t>,
-    ) -> Result<impl Iterator<Item = Result<(DocumentId, obkv::KvReaderU16<'t>)>> + 'a> {
+    ) -> Result<impl Iterator<Item = Result<(DocumentId, CompressedKvReaderU16<'t>)>> + 'a> {
-        self.iter_documents(rtxn, self.documents_ids(rtxn)?)
+        self.iter_compressed_documents(rtxn, self.documents_ids(rtxn)?)
     }
 
     pub fn external_id_of<'a, 't: 'a>(
@@ -1311,8 +1336,15 @@ impl Index {
                 process: "external_id_of",
             })
         })?;
-        Ok(self.iter_documents(rtxn, ids)?.map(move |entry| -> Result<_> {
+        let dictionary = self.document_compression_dictionary(rtxn)?;
-            let (_docid, obkv) = entry?;
+        let mut buffer = Vec::new();
+        Ok(self.iter_compressed_documents(rtxn, ids)?.map(move |entry| -> Result<_> {
+            let (_docid, compressed_obkv) = entry?;
+            let obkv = match dictionary {
+                // TODO manage this unwrap correctly
+                Some(dict) => compressed_obkv.decompress_with(&mut buffer, dict).unwrap(),
+                None => compressed_obkv.as_non_compressed(),
+            };
             match primary_key.document_id(&obkv, &fields)? {
                 Ok(document_id) => Ok(document_id),
                 Err(_) => Err(InternalError::DocumentsError(
@@ -2441,7 +2473,13 @@ pub(crate) mod tests {
         "###);
 
         let rtxn = index.read_txn().unwrap();
-        let (_docid, obkv) = index.documents(&rtxn, [0]).unwrap()[0];
+        let dictionary = index.document_compression_dictionary(&rtxn).unwrap();
+        let (_docid, compressed_obkv) = index.compressed_documents(&rtxn, [0]).unwrap()[0];
+        let mut buffer = Vec::new();
+        let obkv = match dictionary {
+            Some(dict) => compressed_obkv.decompress_with(&mut buffer, dict).unwrap(),
+            None => compressed_obkv.as_non_compressed(),
+        };
         let json = obkv_to_json(&[0, 1, 2], &index.fields_ids_map(&rtxn).unwrap(), obkv).unwrap();
         insta::assert_debug_snapshot!(json, @r###"
         {
@@ -2450,7 +2488,11 @@ pub(crate) mod tests {
         "###);
 
         // Furthermore, when we retrieve document 34, it is not the result of merging 35 with 34
-        let (_docid, obkv) = index.documents(&rtxn, [2]).unwrap()[0];
+        let (_docid, compressed_obkv) = index.compressed_documents(&rtxn, [2]).unwrap()[0];
+        let obkv = match dictionary {
+            Some(dict) => compressed_obkv.decompress_with(&mut buffer, dict).unwrap(),
+            None => compressed_obkv.as_non_compressed(),
+        };
         let json = obkv_to_json(&[0, 1, 2], &index.fields_ids_map(&rtxn).unwrap(), obkv).unwrap();
         insta::assert_debug_snapshot!(json, @r###"
         {
@@ -2657,7 +2699,7 @@ pub(crate) mod tests {
         } = search.execute().unwrap();
         let primary_key_id = index.fields_ids_map(&rtxn).unwrap().id("primary_key").unwrap();
         documents_ids.sort_unstable();
-        let docs = index.documents(&rtxn, documents_ids).unwrap();
+        let docs = index.compressed_documents(&rtxn, documents_ids).unwrap();
         let mut all_ids = HashSet::new();
         for (_docid, obkv) in docs {
             let id = obkv.get(primary_key_id).unwrap();

milli/src/search/new/tests/mod.rs

@@ -24,8 +24,14 @@ fn collect_field_values(
 ) -> Vec<String> {
     let mut values = vec![];
     let fid = index.fields_ids_map(txn).unwrap().id(fid).unwrap();
-    for doc in index.documents(txn, docids.iter().copied()).unwrap() {
+    let mut buffer = Vec::new();
-        if let Some(v) = doc.1.get(fid) {
+    let dictionary = index.document_compression_dictionary(txn).unwrap();
+    for (_id, compressed_doc) in index.compressed_documents(txn, docids.iter().copied()).unwrap() {
+        let doc = match dictionary {
+            Some(dict) => compressed_doc.decompress_with(&mut buffer, dict).unwrap(),
+            None => compressed_doc.as_non_compressed(),
+        };
+        if let Some(v) = doc.get(fid) {
             let v: serde_json::Value = serde_json::from_slice(v).unwrap();
             let v = v.to_string();
             values.push(v);

milli/src/snapshot_tests.rs

@@ -407,9 +407,16 @@ pub fn snap_documents(index: &Index) -> String {
     let rtxn = index.read_txn().unwrap();
     let fields_ids_map = index.fields_ids_map(&rtxn).unwrap();
     let display = fields_ids_map.ids().collect::<Vec<_>>();
+    let dictionary = index.document_compression_dictionary(&rtxn).unwrap();
+    let mut buffer = Vec::new();
 
-    for document in index.all_documents(&rtxn).unwrap() {
+    for result in index.all_compressed_documents(&rtxn).unwrap() {
-        let doc = obkv_to_json(&display, &fields_ids_map, document.unwrap().1).unwrap();
+        let (_id, compressed_document) = result.unwrap();
+        let document = match dictionary {
+            Some(dict) => compressed_document.decompress_with(&mut buffer, dict).unwrap(),
+            None => compressed_document.as_non_compressed(),
+        };
+        let doc = obkv_to_json(&display, &fields_ids_map, document).unwrap();
         snap.push_str(&serde_json::to_string(&doc).unwrap());
         snap.push('\n');
     }

milli/src/update/index_documents/mod.rs

@@ -834,7 +834,7 @@ mod tests {
         let rtxn = index.read_txn().unwrap();
         let count = index.number_of_documents(&rtxn).unwrap();
         assert_eq!(count, 3);
-        let count = index.all_documents(&rtxn).unwrap().count();
+        let count = index.all_compressed_documents(&rtxn).unwrap().count();
         assert_eq!(count, 3);
 
         drop(rtxn);
@@ -861,7 +861,7 @@ mod tests {
         assert_eq!(count, 1);
 
         // Check that we get only one document from the database.
-        let docs = index.documents(&rtxn, Some(0)).unwrap();
+        let docs = index.compressed_documents(&rtxn, Some(0)).unwrap();
         assert_eq!(docs.len(), 1);
         let (id, doc) = docs[0];
         assert_eq!(id, 0);
@@ -882,7 +882,7 @@ mod tests {
         assert_eq!(count, 1);
 
         // Check that we get only one document from the database.
-        let docs = index.documents(&rtxn, Some(0)).unwrap();
+        let docs = index.compressed_documents(&rtxn, Some(0)).unwrap();
         assert_eq!(docs.len(), 1);
         let (id, doc) = docs[0];
         assert_eq!(id, 0);
@@ -932,7 +932,7 @@ mod tests {
         let count = index.number_of_documents(&rtxn).unwrap();
         assert_eq!(count, 3);
 
-        let docs = index.documents(&rtxn, vec![0, 1, 2]).unwrap();
+        let docs = index.compressed_documents(&rtxn, vec![0, 1, 2]).unwrap();
         let (_id, obkv) = docs.iter().find(|(_id, kv)| kv.get(0) == Some(br#""kevin""#)).unwrap();
         let kevin_uuid: String = serde_json::from_slice(obkv.get(1).unwrap()).unwrap();
         drop(rtxn);
@@ -946,7 +946,7 @@ mod tests {
         assert_eq!(count, 3);
 
         // the document 0 has been deleted and reinserted with the id 3
-        let docs = index.documents(&rtxn, vec![1, 2, 0]).unwrap();
+        let docs = index.compressed_documents(&rtxn, vec![1, 2, 0]).unwrap();
         let kevin_position =
             docs.iter().position(|(_, d)| d.get(0).unwrap() == br#""updated kevin""#).unwrap();
         assert_eq!(kevin_position, 2);
@@ -1088,7 +1088,7 @@ mod tests {
         let rtxn = index.read_txn().unwrap();
         let count = index.number_of_documents(&rtxn).unwrap();
         assert_eq!(count, 6);
-        let count = index.all_documents(&rtxn).unwrap().count();
+        let count = index.all_compressed_documents(&rtxn).unwrap().count();
         assert_eq!(count, 6);
 
         db_snap!(index, word_docids, "updated");
@@ -1506,7 +1506,7 @@ mod tests {
         index.add_documents(documents!({ "a" : { "b" : { "c" :  1 }}})).unwrap();
 
         let rtxn = index.read_txn().unwrap();
-        let all_documents_count = index.all_documents(&rtxn).unwrap().count();
+        let all_documents_count = index.all_compressed_documents(&rtxn).unwrap().count();
         assert_eq!(all_documents_count, 1);
         let external_documents_ids = index.external_documents_ids();
         assert!(external_documents_ids.get(&rtxn, "1").unwrap().is_some());
@@ -2796,7 +2796,7 @@ mod tests {
         // Ensuring all the returned IDs actually exists
         let rtxn = index.read_txn().unwrap();
         let res = index.search(&rtxn).execute().unwrap();
-        index.documents(&rtxn, res.documents_ids).unwrap();
+        index.compressed_documents(&rtxn, res.documents_ids).unwrap();
     }
 
     fn delete_documents<'t>(
@@ -3163,7 +3163,7 @@ mod tests {
         let deleted_internal_ids = delete_documents(&mut wtxn, &index, &deleted_external_ids);
 
         // list all documents
-        let results = index.all_documents(&wtxn).unwrap();
+        let results = index.all_compressed_documents(&wtxn).unwrap();
         for result in results {
             let (id, _) = result.unwrap();
             assert!(

milli/src/update/index_documents/transform.rs

@@ -1035,15 +1035,24 @@ impl<'a, 'i> Transform<'a, 'i> {
 
         if original_sorter.is_some() || flattened_sorter.is_some() {
             let modified_faceted_fields = settings_diff.modified_faceted_fields();
+            let dictionary = self.index.document_compression_dictionary(wtxn)?;
+
             let mut original_obkv_buffer = Vec::new();
             let mut flattened_obkv_buffer = Vec::new();
             let mut document_sorter_key_buffer = Vec::new();
+            let mut buffer = Vec::new();
             for result in self.index.external_documents_ids().iter(wtxn)? {
                 let (external_id, docid) = result?;
-                let old_obkv = self.index.documents.get(wtxn, &docid)?.ok_or(
+                let old_compressed_obkv = self.index.documents.get(wtxn, &docid)?.ok_or(
                     InternalError::DatabaseMissingEntry { db_name: db_name::DOCUMENTS, key: None },
                 )?;
 
+                let old_obkv = match dictionary {
+                    // TODO manage this unwrap correctly
+                    Some(dict) => old_compressed_obkv.decompress_with(&mut buffer, dict).unwrap(),
+                    None => old_compressed_obkv.as_non_compressed(),
+                };
+
                 let injected_vectors: std::result::Result<
                     serde_json::Map<String, serde_json::Value>,
                     arroy::Error,

milli/src/update/settings.rs

@@ -1777,7 +1777,7 @@ mod tests {
         // When we search for something that is in the searchable fields
         // we must find the appropriate document.
         let result = index.search(&rtxn).query(r#""kevin""#).execute().unwrap();
-        let documents = index.documents(&rtxn, result.documents_ids).unwrap();
+        let documents = index.compressed_documents(&rtxn, result.documents_ids).unwrap();
         let fid_map = index.fields_ids_map(&rtxn).unwrap();
         assert_eq!(documents.len(), 1);
         assert_eq!(documents[0].1.get(fid_map.id("name").unwrap()), Some(&br#""kevin""#[..]));
@@ -1813,7 +1813,7 @@ mod tests {
         snapshot!(format!("{searchable_fields:?}"), @r###"["id", "name", "age"]"###);
         let result = index.search(&rtxn).query("23").execute().unwrap();
         assert_eq!(result.documents_ids.len(), 1);
-        let documents = index.documents(&rtxn, result.documents_ids).unwrap();
+        let documents = index.compressed_documents(&rtxn, result.documents_ids).unwrap();
         assert_eq!(documents[0].1.get(fid_map.id("name").unwrap()), Some(&br#""kevin""#[..]));
     }
 
@@ -1954,7 +1954,7 @@ mod tests {
         // Only count the field_id 0 and level 0 facet values.
         // TODO we must support typed CSVs for numbers to be understood.
         let fidmap = index.fields_ids_map(&rtxn).unwrap();
-        for document in index.all_documents(&rtxn).unwrap() {
+        for document in index.all_compressed_documents(&rtxn).unwrap() {
             let document = document.unwrap();
             let json = crate::obkv_to_json(&fidmap.ids().collect::<Vec<_>>(), &fidmap, document.1)
                 .unwrap();
@@ -2079,7 +2079,7 @@ mod tests {
         // Run an empty query just to ensure that the search results are ordered.
         let rtxn = index.read_txn().unwrap();
         let SearchResult { documents_ids, .. } = index.search(&rtxn).execute().unwrap();
-        let documents = index.documents(&rtxn, documents_ids).unwrap();
+        let documents = index.compressed_documents(&rtxn, documents_ids).unwrap();
 
         // Fetch the documents "age" field in the ordre in which the documents appear.
         let age_field_id = index.fields_ids_map(&rtxn).unwrap().id("age").unwrap();
@@ -2512,7 +2512,7 @@ mod tests {
         let rtxn = index.read_txn().unwrap();
         let SearchResult { documents_ids, .. } = index.search(&rtxn).query("S").execute().unwrap();
         let first_id = documents_ids[0];
-        let documents = index.documents(&rtxn, documents_ids).unwrap();
+        let documents = index.compressed_documents(&rtxn, documents_ids).unwrap();
         let (_, content) = documents.iter().find(|(id, _)| *id == first_id).unwrap();
 
         let fid = index.fields_ids_map(&rtxn).unwrap().id("title").unwrap();
@@ -2681,7 +2681,7 @@ mod tests {
         wtxn.commit().unwrap();
 
         let rtxn = index.write_txn().unwrap();
-        let docs: StdResult<Vec<_>, _> = index.all_documents(&rtxn).unwrap().collect();
+        let docs: StdResult<Vec<_>, _> = index.all_compressed_documents(&rtxn).unwrap().collect();
         let docs = docs.unwrap();
         assert_eq!(docs.len(), 5);
     }

milli/tests/search/query_criteria.rs

@@ -317,7 +317,8 @@ fn criteria_ascdesc() {
     wtxn.commit().unwrap();
 
     let rtxn = index.read_txn().unwrap();
-    let documents = index.all_documents(&rtxn).unwrap().map(|doc| doc.unwrap()).collect::<Vec<_>>();
+    let documents =
+        index.all_compressed_documents(&rtxn).unwrap().map(|doc| doc.unwrap()).collect::<Vec<_>>();
 
     for criterion in [Asc(S("name")), Desc(S("name")), Asc(S("age")), Desc(S("age"))] {
         eprintln!("Testing with criterion: {:?}", &criterion);