feat: Improve the deserialization time of a Blob

src/data/doc_ids.rs

@@ -1,43 +1,45 @@
 use std::slice::from_raw_parts;
-use std::error::Error;
-use std::path::Path;
 use std::sync::Arc;
 use std::{io, mem};
 
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use sdset::Set;
-use fst::raw::MmapReadOnly;
-use serde::ser::{Serialize, Serializer};
 
 use crate::DocumentId;
-use crate::data::Data;
+use crate::data::SharedData;
 
 #[derive(Default, Clone)]
 pub struct DocIds {
-    data: Data,
+    data: SharedData,
 }
 
 impl DocIds {
-    pub unsafe fn from_path<P: AsRef<Path>>(path: P) -> io::Result<Self> {
-        let mmap = MmapReadOnly::open_path(path)?;
-        let data = Data::Mmap(mmap);
-        Ok(DocIds { data })
-    }
-
-    pub fn from_bytes(vec: Vec<u8>) -> Result<Self, Box<Error>> {
-        // FIXME check if modulo DocumentId
+    pub fn from_bytes(vec: Vec<u8>) -> io::Result<Self> {
         let len = vec.len();
-        let data = Data::Shared {
-            bytes: Arc::new(vec),
-            offset: 0,
-            len: len
-        };
+        DocIds::from_shared_bytes(Arc::new(vec), 0, len)
+    }
+
+    pub fn from_shared_bytes(bytes: Arc<Vec<u8>>, offset: usize, len: usize) -> io::Result<Self> {
+        let data = SharedData { bytes, offset, len };
+        DocIds::from_data(data)
+    }
+
+    fn from_data(data: SharedData) -> io::Result<Self> {
+        let len = data.as_ref().read_u64::<LittleEndian>()?;
+        let data = data.range(mem::size_of::<u64>(), len as usize);
         Ok(DocIds { data })
     }
 
-    pub fn from_document_ids(vec: Vec<DocumentId>) -> Self {
+    pub fn from_raw(vec: Vec<DocumentId>) -> Self {
         DocIds::from_bytes(unsafe { mem::transmute(vec) }).unwrap()
     }
 
+    pub fn write_to_bytes(&self, bytes: &mut Vec<u8>) {
+        let len = self.data.len() as u64;
+        bytes.write_u64::<LittleEndian>(len).unwrap();
+        bytes.extend_from_slice(&self.data);
+    }
+
     pub fn contains(&self, doc: DocumentId) -> bool {
         // FIXME prefer using the sdset::exponential_search function
         self.doc_ids().binary_search(&doc).is_ok()
@@ -51,9 +53,3 @@ impl DocIds {
         Set::new_unchecked(slice)
     }
 }
-
-impl Serialize for DocIds {
-    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        self.data.as_ref().serialize(serializer)
-    }
-}

src/data/doc_indexes.rs

@@ -2,15 +2,13 @@ use std::slice::from_raw_parts;
 use std::io::{self, Write};
 use std::mem::size_of;
 use std::ops::Index;
-use std::path::Path;
 use std::sync::Arc;
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
-use fst::raw::MmapReadOnly;
 use sdset::Set;
 
 use crate::DocIndex;
-use crate::data::Data;
+use crate::data::SharedData;
 
 #[derive(Debug)]
 #[repr(C)]
@@ -21,27 +19,22 @@ struct Range {
 
 #[derive(Clone, Default)]
 pub struct DocIndexes {
-    ranges: Data,
-    indexes: Data,
+    ranges: SharedData,
+    indexes: SharedData,
 }
 
 impl DocIndexes {
-    pub unsafe fn from_path<P: AsRef<Path>>(path: P) -> io::Result<Self> {
-        let mmap = MmapReadOnly::open_path(path)?;
-        DocIndexes::from_data(Data::Mmap(mmap))
-    }
-
     pub fn from_bytes(vec: Vec<u8>) -> io::Result<Self> {
         let len = vec.len();
         DocIndexes::from_shared_bytes(Arc::new(vec), 0, len)
     }
 
     pub fn from_shared_bytes(bytes: Arc<Vec<u8>>, offset: usize, len: usize) -> io::Result<Self> {
-        let data = Data::Shared { bytes, offset, len };
+        let data = SharedData { bytes, offset, len };
         DocIndexes::from_data(data)
     }
 
-    fn from_data(data: Data) -> io::Result<Self> {
+    fn from_data(data: SharedData) -> io::Result<Self> {
         let ranges_len_offset = data.len() - size_of::<u64>();
         let ranges_len = (&data[ranges_len_offset..]).read_u64::<LittleEndian>()?;
         let ranges_len = ranges_len as usize;

src/data/mod.rs

@@ -4,40 +4,30 @@ mod doc_indexes;
 use std::ops::Deref;
 use std::sync::Arc;
 
-use fst::raw::MmapReadOnly;
-
 pub use self::doc_ids::DocIds;
 pub use self::doc_indexes::{DocIndexes, DocIndexesBuilder};
 
 #[derive(Clone)]
-enum Data {
-    Shared {
+struct SharedData {
     bytes: Arc<Vec<u8>>,
     offset: usize,
     len: usize,
-    },
-    Mmap(MmapReadOnly),
 }
 
-impl Data {
-    pub fn range(&self, off: usize, l: usize) -> Data {
-        match self {
-            Data::Shared { bytes, offset, len } => {
-                assert!(off + l <= *len);
-                Data::Shared {
-                    bytes: bytes.clone(),
-                    offset: offset + off,
-                    len: l,
-                }
-            },
-            Data::Mmap(mmap) => Data::Mmap(mmap.range(off, l)),
+impl SharedData {
+    pub fn range(&self, offset: usize, len: usize) -> SharedData {
+        assert!(offset + len <= self.len);
+        SharedData {
+            bytes: self.bytes.clone(),
+            offset: self.offset + offset,
+            len: len,
         }
     }
 }
 
-impl Default for Data {
-    fn default() -> Data {
-        Data::Shared {
+impl Default for SharedData {
+    fn default() -> SharedData {
+        SharedData {
             bytes: Arc::default(),
             offset: 0,
             len: 0,
@@ -45,7 +35,7 @@ impl Default for Data {
     }
 }
 
-impl Deref for Data {
+impl Deref for SharedData {
     type Target = [u8];
 
     fn deref(&self) -> &Self::Target {
@@ -53,13 +43,8 @@ impl Deref for Data {
     }
 }
 
-impl AsRef<[u8]> for Data {
+impl AsRef<[u8]> for SharedData {
     fn as_ref(&self) -> &[u8] {
-        match self {
-            Data::Shared { bytes, offset, len } => {
-                &bytes[*offset..offset + len]
-            },
-            Data::Mmap(m) => m.as_slice(),
-        }
+        &self.bytes[self.offset..self.offset + self.len]
     }
 }

src/database/blob/mod.rs

@@ -6,11 +6,11 @@ pub use self::positive::{PositiveBlob, PositiveBlobBuilder};
 pub use self::negative::NegativeBlob;
 pub use self::ops::OpBuilder;
 
-use std::fmt;
+use std::io::{Cursor, BufRead};
+use std::error::Error;
+use std::sync::Arc;
 
-use serde_derive::{Serialize, Deserialize};
-use serde::ser::{Serialize, Serializer, SerializeTuple};
-use serde::de::{self, Deserialize, Deserializer, SeqAccess, Visitor};
+use byteorder::{ReadBytesExt, WriteBytesExt};
 
 #[derive(Debug)]
 pub enum Blob {
@@ -33,68 +33,41 @@ impl Blob {
             Blob::Negative(_) => Sign::Negative,
         }
     }
-}
 
-impl Serialize for Blob {
-    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        match self {
-            Blob::Positive(blob) => {
-                let mut tuple = serializer.serialize_tuple(2)?;
-                tuple.serialize_element(&Sign::Positive)?;
-                tuple.serialize_element(&blob)?;
-                tuple.end()
-            },
-            Blob::Negative(blob) => {
-                let mut tuple = serializer.serialize_tuple(2)?;
-                tuple.serialize_element(&Sign::Negative)?;
-                tuple.serialize_element(&blob)?;
-                tuple.end()
-            },
-        }
-    }
-}
+    pub fn from_shared_bytes(bytes: Arc<Vec<u8>>, offset: usize, len: usize) -> Result<Blob, Box<Error>> {
+        let mut cursor = Cursor::new(&bytes.as_slice()[..len]);
+        cursor.consume(offset);
 
-impl<'de> Deserialize<'de> for Blob {
-    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Blob, D::Error> {
-        struct TupleVisitor;
-
-        impl<'de> Visitor<'de> for TupleVisitor {
-            type Value = Blob;
-
-            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                formatter.write_str("a Blob struct")
-            }
-
-            #[inline]
-            fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
-                let sign = match seq.next_element()? {
-                    Some(value) => value,
-                    None => return Err(de::Error::invalid_length(0, &self)),
-                };
-                match sign {
+        let byte = cursor.read_u8()?;
+        let blob = match Sign::from_byte(byte)? {
             Sign::Positive => {
-                        let blob = match seq.next_element()? {
-                            Some(value) => value,
-                            None => return Err(de::Error::invalid_length(1, &self)),
-                        };
-                        Ok(Blob::Positive(blob))
+                let offset = cursor.position() as usize;
+                let len = len - offset;
+                let blob = PositiveBlob::from_shared_bytes(bytes, offset, len)?;
+                Blob::Positive(blob)
             },
             Sign::Negative => {
-                        let blob = match seq.next_element()? {
-                            Some(value) => value,
-                            None => return Err(de::Error::invalid_length(1, &self)),
-                        };
-                        Ok(Blob::Negative(blob))
+                let offset = cursor.position() as usize;
+                let len = len - offset;
+                let blob = NegativeBlob::from_shared_bytes(bytes, offset, len)?;
+                Blob::Negative(blob)
             },
+        };
+
+        Ok(blob)
+    }
+
+    pub fn write_to_bytes(&self, bytes: &mut Vec<u8>) {
+        let sign = self.sign();
+        sign.write_to_bytes(bytes);
+        match self {
+            Blob::Positive(b) => b.write_to_bytes(bytes),
+            Blob::Negative(b) => b.write_to_bytes(bytes),
         }
     }
 }
 
-        deserializer.deserialize_tuple(2, TupleVisitor)
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Sign {
     Positive,
     Negative,
@@ -107,4 +80,19 @@ impl Sign {
             Sign::Negative => Sign::Positive,
         }
     }
+
+    pub fn from_byte(byte: u8) -> Result<Sign, Box<Error>> {
+        match byte {
+            0 => Ok(Sign::Positive),
+            1 => Ok(Sign::Negative),
+            b => Err(format!("Invalid sign byte {:?}", b).into()),
+        }
+    }
+
+    pub fn write_to_bytes(&self, bytes: &mut Vec<u8>) {
+        match self {
+            Sign::Positive => bytes.write_u8(0).unwrap(),
+            Sign::Negative => bytes.write_u8(1).unwrap(),
+        }
+    }
 }

src/database/blob/negative/blob.rs

@@ -1,10 +1,11 @@
+use std::io::{Cursor, BufRead};
 use std::error::Error;
-use std::path::Path;
+use std::sync::Arc;
 use std::fmt;
 
 use sdset::Set;
-use serde::de::{self, Deserialize, Deserializer};
-use serde::ser::{Serialize, Serializer};
+use byteorder::{LittleEndian, ReadBytesExt};
+
 use crate::data::DocIds;
 use crate::DocumentId;
 
@@ -14,18 +15,26 @@ pub struct NegativeBlob {
 }
 
 impl NegativeBlob {
-    pub unsafe fn from_path<P>(doc_ids: P) -> Result<Self, Box<Error>>
-    where P: AsRef<Path>,
-    {
-        let doc_ids = DocIds::from_path(doc_ids)?;
-        Ok(NegativeBlob { doc_ids })
-    }
-
     pub fn from_bytes(doc_ids: Vec<u8>) -> Result<Self, Box<Error>> {
         let doc_ids = DocIds::from_bytes(doc_ids)?;
         Ok(NegativeBlob { doc_ids })
     }
 
+    pub fn from_shared_bytes(bytes: Arc<Vec<u8>>, offset: usize, len: usize) -> Result<Self, Box<Error>> {
+        let mut cursor = Cursor::new(&bytes.as_slice()[..len]);
+        cursor.consume(offset);
+
+        let len = cursor.read_u64::<LittleEndian>()? as usize;
+        let offset = cursor.position() as usize;
+        let doc_ids = DocIds::from_shared_bytes(bytes, offset, len)?;
+
+        Ok(NegativeBlob::from_raw(doc_ids))
+    }
+
+    pub fn write_to_bytes(&self, bytes: &mut Vec<u8>) {
+        self.doc_ids.write_to_bytes(bytes)
+    }
+
     pub fn from_raw(doc_ids: DocIds) -> Self {
         NegativeBlob { doc_ids }
     }
@@ -52,16 +61,3 @@ impl fmt::Debug for NegativeBlob {
         write!(f, ")")
     }
 }
-
-impl Serialize for NegativeBlob {
-    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        self.doc_ids.serialize(serializer)
-    }
-}
-
-impl<'de> Deserialize<'de> for NegativeBlob {
-    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<NegativeBlob, D::Error> {
-        let bytes = Vec::deserialize(deserializer)?;
-        NegativeBlob::from_bytes(bytes).map_err(de::Error::custom)
-    }
-}

src/database/blob/negative/ops.rs

@@ -60,7 +60,7 @@ impl<'a> $name<'a> {
 
     pub fn into_negative_blob(self) -> NegativeBlob {
         let document_ids = sdset::SetOperation::into_set_buf(self.op);
-        let doc_ids = DocIds::from_document_ids(document_ids.into_vec());
+        let doc_ids = DocIds::from_raw(document_ids.into_vec());
         NegativeBlob::from_raw(doc_ids)
     }
 }

src/database/blob/positive/blob.rs

@@ -1,15 +1,16 @@
-use std::fmt;
-use std::io::Write;
-use std::path::Path;
+use std::io::{Write, Cursor, BufRead};
+use std::convert::From;
 use std::error::Error;
+use std::sync::Arc;
+use std::fmt;
 
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use fst::{map, Map, Streamer, IntoStreamer};
+use fst::raw::Fst;
 use sdset::Set;
 
 use crate::DocIndex;
 use crate::data::{DocIndexes, DocIndexesBuilder};
-use serde::ser::{Serialize, Serializer, SerializeTuple};
-use serde::de::{self, Deserialize, Deserializer, SeqAccess, Visitor};
 
 #[derive(Default)]
 pub struct PositiveBlob {
@@ -18,15 +19,6 @@ pub struct PositiveBlob {
 }
 
 impl PositiveBlob {
-    pub unsafe fn from_paths<P, Q>(map: P, indexes: Q) -> Result<Self, Box<Error>>
-    where P: AsRef<Path>,
-          Q: AsRef<Path>,
-    {
-        let map = Map::from_path(map)?;
-        let indexes = DocIndexes::from_path(indexes)?;
-        Ok(PositiveBlob { map, indexes })
-    }
-
     pub fn from_bytes(map: Vec<u8>, indexes: Vec<u8>) -> Result<Self, Box<Error>> {
         let map = Map::from_bytes(map)?;
         let indexes = DocIndexes::from_bytes(indexes)?;
@@ -37,6 +29,33 @@ impl PositiveBlob {
         PositiveBlob { map, indexes }
     }
 
+    pub fn from_shared_bytes(bytes: Arc<Vec<u8>>, offset: usize, len: usize) -> Result<Self, Box<Error>> {
+        let mut cursor = Cursor::new(&bytes.as_slice()[..len]);
+        cursor.consume(offset);
+
+        let map_len = cursor.read_u64::<LittleEndian>()? as usize;
+        let offset = cursor.position() as usize;
+        let map = Map::from(Fst::from_shared_bytes(bytes.clone(), offset, map_len)?);
+
+        cursor.consume(map_len);
+
+        let doc_len = cursor.read_u64::<LittleEndian>()? as usize;
+        let offset = cursor.position() as usize;
+        let doc_indexes = DocIndexes::from_shared_bytes(bytes, offset, doc_len)?;
+
+        Ok(PositiveBlob::from_raw(map, doc_indexes))
+    }
+
+    pub fn write_to_bytes(&self, bytes: &mut Vec<u8>) {
+        let map_bytes = self.map.as_fst().as_bytes();
+        bytes.write_u64::<LittleEndian>(map_bytes.len() as u64).unwrap();
+        bytes.extend_from_slice(&map_bytes);
+
+        let doc_indexes_vec = self.indexes.to_vec(); // FIXME patch to have a as_slice() function
+        bytes.write_u64::<LittleEndian>(doc_indexes_vec.len() as u64).unwrap();
+        bytes.extend_from_slice(&doc_indexes_vec);
+    }
+
     pub fn get<K: AsRef<[u8]>>(&self, key: K) -> Option<&[DocIndex]> {
         self.map.get(key).map(|index| &self.indexes[index as usize])
     }
@@ -103,52 +122,6 @@ impl<'m, 'a> Streamer<'a> for PositiveBlobStream<'m> {
     }
 }
 
-impl Serialize for PositiveBlob {
-    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        let mut tuple = serializer.serialize_tuple(2)?;
-        tuple.serialize_element(&self.map.as_fst().to_vec())?;
-        tuple.serialize_element(&self.indexes.to_vec())?;
-        tuple.end()
-    }
-}
-
-impl<'de> Deserialize<'de> for PositiveBlob {
-    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<PositiveBlob, D::Error> {
-        struct TupleVisitor;
-
-        impl<'de> Visitor<'de> for TupleVisitor {
-            type Value = PositiveBlob;
-
-            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                formatter.write_str("a PositiveBlob struct")
-            }
-
-            #[inline]
-            fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
-                let map = match seq.next_element()? {
-                    Some(bytes) => match Map::from_bytes(bytes) {
-                        Ok(value) => value,
-                        Err(err) => return Err(de::Error::custom(err)),
-                    },
-                    None => return Err(de::Error::invalid_length(0, &self)),
-                };
-
-                let indexes = match seq.next_element()? {
-                    Some(bytes) => match DocIndexes::from_bytes(bytes) {
-                        Ok(value) => value,
-                        Err(err) => return Err(de::Error::custom(err)),
-                    },
-                    None => return Err(de::Error::invalid_length(1, &self)),
-                };
-
-                Ok(PositiveBlob { map, indexes })
-            }
-        }
-
-        deserializer.deserialize_tuple(2, TupleVisitor)
-    }
-}
-
 pub struct PositiveBlobBuilder<W, X> {
     map: fst::MapBuilder<W>,
     indexes: DocIndexesBuilder<X>,
@@ -207,6 +180,29 @@ mod tests {
 
     use crate::DocumentId;
 
+    #[test]
+    fn create_query() -> Result<(), Box<Error>> {
+        let a = DocIndex { document_id: DocumentId(0), attribute: Attribute::new(3, 11), word_area: WordArea::new(30, 4) };
+        let b = DocIndex { document_id: DocumentId(1), attribute: Attribute::new(4, 21), word_area: WordArea::new(35, 6) };
+        let c = DocIndex { document_id: DocumentId(2), attribute: Attribute::new(8, 2), word_area: WordArea::new(89, 6) };
+
+        let mut builder = PositiveBlobBuilder::memory();
+
+        builder.insert("aaa", Set::new(&[a])?)?;
+        builder.insert("aab", Set::new(&[a, b, c])?)?;
+        builder.insert("aac", Set::new(&[a, c])?)?;
+
+        let (map_bytes, indexes_bytes) = builder.into_inner()?;
+        let positive_blob = PositiveBlob::from_bytes(map_bytes, indexes_bytes)?;
+
+        assert_eq!(positive_blob.get("aaa"), Some(&[a][..]));
+        assert_eq!(positive_blob.get("aab"), Some(&[a, b, c][..]));
+        assert_eq!(positive_blob.get("aac"), Some(&[a, c][..]));
+        assert_eq!(positive_blob.get("aad"), None);
+
+        Ok(())
+    }
+
     #[test]
     fn serialize_deserialize() -> Result<(), Box<Error>> {
         let a = DocIndex {
@@ -269,9 +265,6 @@ mod tests {
         let (map_bytes, indexes_bytes) = builder.into_inner()?;
         let positive_blob = PositiveBlob::from_bytes(map_bytes, indexes_bytes)?;
 
-        let bytes = bincode::serialize(&positive_blob)?;
-        let positive_blob: PositiveBlob = bincode::deserialize(&bytes)?;
-
         assert_eq!(positive_blob.get("aaa"), Some(&[a][..]));
         assert_eq!(positive_blob.get("aab"), Some(&[a, b, c][..]));
         assert_eq!(positive_blob.get("aac"), Some(&[a, c][..]));

src/database/database.rs

@@ -7,9 +7,9 @@ use rocksdb::rocksdb::{Writable, Snapshot};
 use rocksdb::{DB, DBVector, MergeOperands};
 use crossbeam::atomic::ArcCell;
 
+use crate::database::blob::{self, Blob, PositiveBlob};
 use crate::database::{DatabaseView, Update, Schema};
 use crate::database::{DATA_INDEX, DATA_SCHEMA};
-use crate::database::blob::{self, Blob};
 
 pub struct Database {
     // DB is under a Mutex to sync update ingestions and separate DB update locking
@@ -136,18 +136,31 @@ fn merge_indexes(key: &[u8], existing_value: Option<&[u8]>, operands: &mut Merge
     };
 
     let mut op = blob::OpBuilder::with_capacity(capacity);
-    if let Some(existing_value) = existing_value {
-        let blob = bincode::deserialize(existing_value).expect("BUG: could not deserialize data-index");
+    if let Some(bytes) = existing_value {
+        let bytes_len = bytes.len();
+        let bytes = Arc::new(bytes.to_vec());
+        let blob = match PositiveBlob::from_shared_bytes(bytes, 0, bytes_len) {
+            Ok(blob) => blob,
+            Err(e) => panic!("BUG: could not deserialize data-index due to {}", e),
+        };
         op.push(Blob::Positive(blob));
     }
 
     for bytes in operands {
-        let blob = bincode::deserialize(bytes).expect("BUG: could not deserialize blob");
+        let bytes_len = bytes.len();
+        let bytes = Arc::new(bytes.to_vec());
+        let blob = match Blob::from_shared_bytes(bytes, 0, bytes_len) {
+            Ok(blob) => blob,
+            Err(e) => panic!("BUG: could not deserialize blob due to {}", e),
+        };
         op.push(blob);
     }
 
     let blob = op.merge().expect("BUG: could not merge blobs");
-    bincode::serialize(&blob).expect("BUG: could not serialize merged blob")
+
+    let mut bytes = Vec::new();
+    blob.write_to_bytes(&mut bytes);
+    bytes
 }
 
 #[cfg(test)]
@@ -158,9 +171,9 @@ mod tests {
     use serde_derive::{Serialize, Deserialize};
     use tempfile::tempdir;
 
-    use crate::tokenizer::DefaultBuilder;
-    use crate::database::update::PositiveUpdateBuilder;
     use crate::database::schema::{SchemaBuilder, STORED, INDEXED};
+    use crate::database::update::PositiveUpdateBuilder;
+    use crate::tokenizer::DefaultBuilder;
 
     #[test]
     fn ingest_update_file() -> Result<(), Box<Error>> {

src/database/mod.rs

@@ -2,6 +2,7 @@ use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
 use std::error::Error;
 use std::ops::Deref;
+use std::sync::Arc;
 
 use rocksdb::rocksdb::{DB, Snapshot};
 
@@ -55,7 +56,11 @@ fn retrieve_data_index<D>(snapshot: &Snapshot<D>) -> Result<PositiveBlob, Box<Er
 where D: Deref<Target=DB>
 {
     match snapshot.get(DATA_INDEX)? {
-        Some(vector) => Ok(bincode::deserialize(&*vector)?),
+        Some(vector) => {
+            let bytes_len = vector.as_ref().len();
+            let bytes = Arc::new(vector.as_ref().to_vec());
+            Ok(PositiveBlob::from_shared_bytes(bytes, 0, bytes_len)?)
+        },
         None => Ok(PositiveBlob::default()),
     }
 }

src/database/update/negative/update.rs

@@ -38,7 +38,8 @@ impl NegativeUpdateBuilder {
         let blob = Blob::Negative(negative_blob);
 
         // write the data-index aka negative blob
-        let bytes = bincode::serialize(&blob)?;
+        let mut bytes = Vec::new();
+        blob.write_to_bytes(&mut bytes);
         file_writer.merge(DATA_INDEX, &bytes)?;
 
         // FIXME remove this ugly thing !

src/database/update/positive/update.rs

@@ -485,7 +485,8 @@ impl<B> PositiveUpdateBuilder<B> {
         let blob = Blob::Positive(positive_blob);
 
         // write the data-index aka positive blob
-        let bytes = bincode::serialize(&blob)?;
+        let mut bytes = Vec::new();
+        blob.write_to_bytes(&mut bytes);
         file_writer.merge(DATA_INDEX, &bytes)?;
 
         // write all the documents fields updates