From 78535b3e3342d9ffaaf2a663842c02b0707ba98d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Renault?= <clement@meilisearch.com>
Date: Mon, 21 Oct 2019 12:05:53 +0200
Subject: [PATCH] Move to heed 0.1.0

---
 meilidb-core/Cargo.toml                       |  6 +--
 meilidb-core/src/automaton/mod.rs             |  4 +-
 meilidb-core/src/database.rs                  | 21 ++++-----
 meilidb-core/src/error.rs                     |  8 ++--
 meilidb-core/src/query_builder.rs             |  8 ++--
 meilidb-core/src/serde/deserializer.rs        | 10 ++---
 meilidb-core/src/serde/mod.rs                 |  8 ++--
 meilidb-core/src/store/docs_words.rs          | 16 +++----
 meilidb-core/src/store/documents_fields.rs    | 16 +++----
 .../src/store/documents_fields_counts.rs      | 27 ++++++------
 meilidb-core/src/store/main.rs                | 43 ++++++++++---------
 meilidb-core/src/store/mod.rs                 | 18 ++++----
 meilidb-core/src/store/postings_lists.rs      | 12 +++---
 meilidb-core/src/store/synonyms.rs            | 12 +++---
 meilidb-core/src/store/updates.rs             | 42 ++++--------------
 meilidb-core/src/store/updates_results.rs     | 12 +++---
 meilidb-core/src/update/customs_update.rs     |  6 +--
 meilidb-core/src/update/documents_addition.rs |  6 +--
 meilidb-core/src/update/documents_deletion.rs |  6 +--
 meilidb-core/src/update/mod.rs                | 11 ++---
 meilidb-core/src/update/schema_update.rs      |  4 +-
 meilidb-core/src/update/synonyms_addition.rs  |  6 +--
 meilidb-core/src/update/synonyms_deletion.rs  |  6 +--
 23 files changed, 132 insertions(+), 176 deletions(-)

diff --git a/meilidb-core/Cargo.toml b/meilidb-core/Cargo.toml
index 0469996e2..2e6a5fb5d 100644
--- a/meilidb-core/Cargo.toml
+++ b/meilidb-core/Cargo.toml
@@ -12,6 +12,7 @@ crossbeam-channel = "0.3.9"
 deunicode = "1.0.0"
 env_logger = "0.7.0"
 hashbrown = { version = "0.6.0", features = ["serde"] }
+heed = "0.1.0"
 log = "0.4.8"
 meilidb-schema = { path = "../meilidb-schema", version = "0.1.0" }
 meilidb-tokenizer = { path = "../meilidb-tokenizer", version = "0.1.0" }
@@ -24,11 +25,6 @@ siphasher = "0.3.0"
 slice-group-by = "0.2.6"
 zerocopy = "0.2.8"
 
-[dependencies.zlmdb]
-package = "zerocopy-lmdb"
-git = "https://github.com/Kerollmops/zerocopy-lmdb.git"
-branch = "master"
-
 [dependencies.levenshtein_automata]
 git = "https://github.com/Kerollmops/levenshtein-automata.git"
 branch = "arc-byte-slice"
diff --git a/meilidb-core/src/automaton/mod.rs b/meilidb-core/src/automaton/mod.rs
index da398c669..1bfb41e67 100644
--- a/meilidb-core/src/automaton/mod.rs
+++ b/meilidb-core/src/automaton/mod.rs
@@ -23,7 +23,7 @@ pub struct AutomatonProducer {
 
 impl AutomatonProducer {
     pub fn new(
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         query: &str,
         main_store: store::Main,
         synonyms_store: store::Synonyms,
@@ -103,7 +103,7 @@ pub fn normalize_str(string: &str) -> String {
 }
 
 fn generate_automatons(
-    reader: &zlmdb::RoTxn,
+    reader: &heed::RoTxn,
     query: &str,
     main_store: store::Main,
     synonym_store: store::Synonyms,
diff --git a/meilidb-core/src/database.rs b/meilidb-core/src/database.rs
index 64da2d5f9..79f4d731e 100644
--- a/meilidb-core/src/database.rs
+++ b/meilidb-core/src/database.rs
@@ -5,9 +5,9 @@ use std::sync::{Arc, RwLock};
 use std::{fs, thread};
 
 use crossbeam_channel::Receiver;
+use heed::types::{Str, Unit};
+use heed::{CompactionOption, Result as ZResult};
 use log::{debug, error};
-use zlmdb::types::{Str, Unit};
-use zlmdb::{CompactionOption, Result as ZResult};
 
 use crate::{store, update, Index, MResult};
 
@@ -15,18 +15,13 @@ pub type BoxUpdateFn = Box<dyn Fn(update::UpdateResult) + Send + Sync + 'static>
 type ArcSwapFn = arc_swap::ArcSwapOption<BoxUpdateFn>;
 
 pub struct Database {
-    pub env: zlmdb::Env,
-    common_store: zlmdb::DynDatabase,
-    indexes_store: zlmdb::Database<Str, Unit>,
+    pub env: heed::Env,
+    common_store: heed::PolyDatabase,
+    indexes_store: heed::Database<Str, Unit>,
     indexes: RwLock<HashMap<String, (Index, Arc<ArcSwapFn>, thread::JoinHandle<()>)>>,
 }
 
-fn update_awaiter(
-    receiver: Receiver<()>,
-    env: zlmdb::Env,
-    update_fn: Arc<ArcSwapFn>,
-    index: Index,
-) {
+fn update_awaiter(receiver: Receiver<()>, env: heed::Env, update_fn: Arc<ArcSwapFn>, index: Index) {
     for () in receiver {
         // consume all updates in order (oldest first)
         loop {
@@ -67,7 +62,7 @@ impl Database {
     pub fn open_or_create(path: impl AsRef<Path>) -> MResult<Database> {
         fs::create_dir_all(path.as_ref())?;
 
-        let env = zlmdb::EnvOpenOptions::new()
+        let env = heed::EnvOpenOptions::new()
             .map_size(10 * 1024 * 1024 * 1024) // 10GB
             .max_dbs(3000)
             .open(path)?;
@@ -199,7 +194,7 @@ impl Database {
         Ok(indexes.keys().cloned().collect())
     }
 
-    pub fn common_store(&self) -> zlmdb::DynDatabase {
+    pub fn common_store(&self) -> heed::PolyDatabase {
         self.common_store
     }
 }
diff --git a/meilidb-core/src/error.rs b/meilidb-core/src/error.rs
index a39164341..986f1d08b 100644
--- a/meilidb-core/src/error.rs
+++ b/meilidb-core/src/error.rs
@@ -12,7 +12,7 @@ pub enum Error {
     SchemaMissing,
     WordIndexMissing,
     MissingDocumentId,
-    Zlmdb(zlmdb::Error),
+    Zlmdb(heed::Error),
     Fst(fst::Error),
     SerdeJson(SerdeJsonError),
     Bincode(bincode::Error),
@@ -27,8 +27,8 @@ impl From<io::Error> for Error {
     }
 }
 
-impl From<zlmdb::Error> for Error {
-    fn from(error: zlmdb::Error) -> Error {
+impl From<heed::Error> for Error {
+    fn from(error: heed::Error) -> Error {
         Error::Zlmdb(error)
     }
 }
@@ -79,7 +79,7 @@ impl fmt::Display for Error {
             SchemaMissing => write!(f, "this index does not have a schema"),
             WordIndexMissing => write!(f, "this index does not have a word index"),
             MissingDocumentId => write!(f, "document id is missing"),
-            Zlmdb(e) => write!(f, "zlmdb error; {}", e),
+            Zlmdb(e) => write!(f, "heed error; {}", e),
             Fst(e) => write!(f, "fst error; {}", e),
             SerdeJson(e) => write!(f, "serde json error; {}", e),
             Bincode(e) => write!(f, "bincode error; {}", e),
diff --git a/meilidb-core/src/query_builder.rs b/meilidb-core/src/query_builder.rs
index 3d0769ec3..02c299a2a 100644
--- a/meilidb-core/src/query_builder.rs
+++ b/meilidb-core/src/query_builder.rs
@@ -137,7 +137,7 @@ fn multiword_rewrite_matches(
 }
 
 fn fetch_raw_documents(
-    reader: &zlmdb::RoTxn,
+    reader: &heed::RoTxn,
     automatons: &[Automaton],
     query_enhancer: &QueryEnhancer,
     searchables: Option<&ReorderedAttrs>,
@@ -285,7 +285,7 @@ impl<'c, 'f, 'd> QueryBuilder<'c, 'f, 'd> {
 
     pub fn query(
         self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         query: &str,
         range: Range<usize>,
     ) -> MResult<Vec<Document>> {
@@ -323,7 +323,7 @@ impl<'c, 'f, 'd> QueryBuilder<'c, 'f, 'd> {
 }
 
 fn raw_query<'c, FI>(
-    reader: &zlmdb::RoTxn,
+    reader: &heed::RoTxn,
 
     query: &str,
     range: Range<usize>,
@@ -454,7 +454,7 @@ where
 }
 
 fn raw_query_with_distinct<'c, FI, FD>(
-    reader: &zlmdb::RoTxn,
+    reader: &heed::RoTxn,
 
     query: &str,
     range: Range<usize>,
diff --git a/meilidb-core/src/serde/deserializer.rs b/meilidb-core/src/serde/deserializer.rs
index 3c99b365b..3c6955cdf 100644
--- a/meilidb-core/src/serde/deserializer.rs
+++ b/meilidb-core/src/serde/deserializer.rs
@@ -14,7 +14,7 @@ use crate::DocumentId;
 #[derive(Debug)]
 pub enum DeserializerError {
     SerdeJson(SerdeJsonError),
-    Zlmdb(zlmdb::Error),
+    Zlmdb(heed::Error),
     Custom(String),
 }
 
@@ -28,7 +28,7 @@ impl fmt::Display for DeserializerError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             DeserializerError::SerdeJson(e) => write!(f, "serde json related error: {}", e),
-            DeserializerError::Zlmdb(e) => write!(f, "zlmdb related error: {}", e),
+            DeserializerError::Zlmdb(e) => write!(f, "heed related error: {}", e),
             DeserializerError::Custom(s) => f.write_str(s),
         }
     }
@@ -42,15 +42,15 @@ impl From<SerdeJsonError> for DeserializerError {
     }
 }
 
-impl From<zlmdb::Error> for DeserializerError {
-    fn from(error: zlmdb::Error) -> DeserializerError {
+impl From<heed::Error> for DeserializerError {
+    fn from(error: heed::Error) -> DeserializerError {
         DeserializerError::Zlmdb(error)
     }
 }
 
 pub struct Deserializer<'a> {
     pub document_id: DocumentId,
-    pub reader: &'a zlmdb::RoTxn,
+    pub reader: &'a heed::RoTxn,
     pub documents_fields: DocumentsFields,
     pub schema: &'a Schema,
     pub attributes: Option<&'a HashSet<SchemaAttr>>,
diff --git a/meilidb-core/src/serde/mod.rs b/meilidb-core/src/serde/mod.rs
index c2feafbf0..12ba1286a 100644
--- a/meilidb-core/src/serde/mod.rs
+++ b/meilidb-core/src/serde/mod.rs
@@ -35,7 +35,7 @@ use crate::{DocumentId, ParseNumberError};
 pub enum SerializerError {
     DocumentIdNotFound,
     InvalidDocumentIdType,
-    Zlmdb(zlmdb::Error),
+    Zlmdb(heed::Error),
     SerdeJson(SerdeJsonError),
     ParseNumber(ParseNumberError),
     UnserializableType { type_name: &'static str },
@@ -59,7 +59,7 @@ impl fmt::Display for SerializerError {
             SerializerError::InvalidDocumentIdType => {
                 f.write_str("document identifier can only be of type string or number")
             }
-            SerializerError::Zlmdb(e) => write!(f, "zlmdb related error: {}", e),
+            SerializerError::Zlmdb(e) => write!(f, "heed related error: {}", e),
             SerializerError::SerdeJson(e) => write!(f, "serde json error: {}", e),
             SerializerError::ParseNumber(e) => {
                 write!(f, "error while trying to parse a number: {}", e)
@@ -92,8 +92,8 @@ impl From<SerdeJsonError> for SerializerError {
     }
 }
 
-impl From<zlmdb::Error> for SerializerError {
-    fn from(error: zlmdb::Error) -> SerializerError {
+impl From<heed::Error> for SerializerError {
+    fn from(error: heed::Error) -> SerializerError {
         SerializerError::Zlmdb(error)
     }
 }
diff --git a/meilidb-core/src/store/docs_words.rs b/meilidb-core/src/store/docs_words.rs
index 93d4192e3..b7ef6e542 100644
--- a/meilidb-core/src/store/docs_words.rs
+++ b/meilidb-core/src/store/docs_words.rs
@@ -1,18 +1,18 @@
 use super::BEU64;
 use crate::DocumentId;
+use heed::types::{ByteSlice, OwnedType};
+use heed::Result as ZResult;
 use std::sync::Arc;
-use zlmdb::types::{ByteSlice, OwnedType};
-use zlmdb::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct DocsWords {
-    pub(crate) docs_words: zlmdb::Database<OwnedType<BEU64>, ByteSlice>,
+    pub(crate) docs_words: heed::Database<OwnedType<BEU64>, ByteSlice>,
 }
 
 impl DocsWords {
     pub fn put_doc_words(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         document_id: DocumentId,
         words: &fst::Set,
     ) -> ZResult<()> {
@@ -21,18 +21,14 @@ impl DocsWords {
         self.docs_words.put(writer, &document_id, bytes)
     }
 
-    pub fn del_doc_words(
-        self,
-        writer: &mut zlmdb::RwTxn,
-        document_id: DocumentId,
-    ) -> ZResult<bool> {
+    pub fn del_doc_words(self, writer: &mut heed::RwTxn, document_id: DocumentId) -> ZResult<bool> {
         let document_id = BEU64::new(document_id.0);
         self.docs_words.delete(writer, &document_id)
     }
 
     pub fn doc_words(
         self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         document_id: DocumentId,
     ) -> ZResult<Option<fst::Set>> {
         let document_id = BEU64::new(document_id.0);
diff --git a/meilidb-core/src/store/documents_fields.rs b/meilidb-core/src/store/documents_fields.rs
index 84b53351b..17fa20380 100644
--- a/meilidb-core/src/store/documents_fields.rs
+++ b/meilidb-core/src/store/documents_fields.rs
@@ -1,19 +1,19 @@
+use heed::types::{ByteSlice, OwnedType};
+use heed::Result as ZResult;
 use meilidb_schema::SchemaAttr;
-use zlmdb::types::{ByteSlice, OwnedType};
-use zlmdb::Result as ZResult;
 
 use super::DocumentAttrKey;
 use crate::DocumentId;
 
 #[derive(Copy, Clone)]
 pub struct DocumentsFields {
-    pub(crate) documents_fields: zlmdb::Database<OwnedType<DocumentAttrKey>, ByteSlice>,
+    pub(crate) documents_fields: heed::Database<OwnedType<DocumentAttrKey>, ByteSlice>,
 }
 
 impl DocumentsFields {
     pub fn put_document_field(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         document_id: DocumentId,
         attribute: SchemaAttr,
         value: &[u8],
@@ -24,7 +24,7 @@ impl DocumentsFields {
 
     pub fn del_all_document_fields(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         document_id: DocumentId,
     ) -> ZResult<usize> {
         let start = DocumentAttrKey::new(document_id, SchemaAttr::min());
@@ -34,7 +34,7 @@ impl DocumentsFields {
 
     pub fn document_attribute<'txn>(
         self,
-        reader: &'txn zlmdb::RoTxn,
+        reader: &'txn heed::RoTxn,
         document_id: DocumentId,
         attribute: SchemaAttr,
     ) -> ZResult<Option<&'txn [u8]>> {
@@ -44,7 +44,7 @@ impl DocumentsFields {
 
     pub fn document_fields<'txn>(
         self,
-        reader: &'txn zlmdb::RoTxn,
+        reader: &'txn heed::RoTxn,
         document_id: DocumentId,
     ) -> ZResult<DocumentFieldsIter<'txn>> {
         let start = DocumentAttrKey::new(document_id, SchemaAttr::min());
@@ -55,7 +55,7 @@ impl DocumentsFields {
 }
 
 pub struct DocumentFieldsIter<'txn> {
-    iter: zlmdb::RoRange<'txn, OwnedType<DocumentAttrKey>, ByteSlice>,
+    iter: heed::RoRange<'txn, OwnedType<DocumentAttrKey>, ByteSlice>,
 }
 
 impl<'txn> Iterator for DocumentFieldsIter<'txn> {
diff --git a/meilidb-core/src/store/documents_fields_counts.rs b/meilidb-core/src/store/documents_fields_counts.rs
index b765c8f25..5b7853ed6 100644
--- a/meilidb-core/src/store/documents_fields_counts.rs
+++ b/meilidb-core/src/store/documents_fields_counts.rs
@@ -1,18 +1,18 @@
 use super::DocumentAttrKey;
 use crate::DocumentId;
+use heed::types::OwnedType;
+use heed::Result as ZResult;
 use meilidb_schema::SchemaAttr;
-use zlmdb::types::OwnedType;
-use zlmdb::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct DocumentsFieldsCounts {
-    pub(crate) documents_fields_counts: zlmdb::Database<OwnedType<DocumentAttrKey>, OwnedType<u64>>,
+    pub(crate) documents_fields_counts: heed::Database<OwnedType<DocumentAttrKey>, OwnedType<u64>>,
 }
 
 impl DocumentsFieldsCounts {
     pub fn put_document_field_count(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         document_id: DocumentId,
         attribute: SchemaAttr,
         value: u64,
@@ -23,7 +23,7 @@ impl DocumentsFieldsCounts {
 
     pub fn del_all_document_fields_counts(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         document_id: DocumentId,
     ) -> ZResult<usize> {
         let start = DocumentAttrKey::new(document_id, SchemaAttr::min());
@@ -34,7 +34,7 @@ impl DocumentsFieldsCounts {
 
     pub fn document_field_count(
         self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         document_id: DocumentId,
         attribute: SchemaAttr,
     ) -> ZResult<Option<u64>> {
@@ -47,7 +47,7 @@ impl DocumentsFieldsCounts {
 
     pub fn document_fields_counts<'txn>(
         self,
-        reader: &'txn zlmdb::RoTxn,
+        reader: &'txn heed::RoTxn,
         document_id: DocumentId,
     ) -> ZResult<DocumentFieldsCountsIter<'txn>> {
         let start = DocumentAttrKey::new(document_id, SchemaAttr::min());
@@ -56,10 +56,7 @@ impl DocumentsFieldsCounts {
         Ok(DocumentFieldsCountsIter { iter })
     }
 
-    pub fn documents_ids<'txn>(
-        self,
-        reader: &'txn zlmdb::RoTxn,
-    ) -> ZResult<DocumentsIdsIter<'txn>> {
+    pub fn documents_ids<'txn>(self, reader: &'txn heed::RoTxn) -> ZResult<DocumentsIdsIter<'txn>> {
         let iter = self.documents_fields_counts.iter(reader)?;
         Ok(DocumentsIdsIter {
             last_seen_id: None,
@@ -69,7 +66,7 @@ impl DocumentsFieldsCounts {
 
     pub fn all_documents_fields_counts<'txn>(
         self,
-        reader: &'txn zlmdb::RoTxn,
+        reader: &'txn heed::RoTxn,
     ) -> ZResult<AllDocumentsFieldsCountsIter<'txn>> {
         let iter = self.documents_fields_counts.iter(reader)?;
         Ok(AllDocumentsFieldsCountsIter { iter })
@@ -77,7 +74,7 @@ impl DocumentsFieldsCounts {
 }
 
 pub struct DocumentFieldsCountsIter<'txn> {
-    iter: zlmdb::RoRange<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
+    iter: heed::RoRange<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
 }
 
 impl Iterator for DocumentFieldsCountsIter<'_> {
@@ -97,7 +94,7 @@ impl Iterator for DocumentFieldsCountsIter<'_> {
 
 pub struct DocumentsIdsIter<'txn> {
     last_seen_id: Option<DocumentId>,
-    iter: zlmdb::RoIter<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
+    iter: heed::RoIter<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
 }
 
 impl Iterator for DocumentsIdsIter<'_> {
@@ -121,7 +118,7 @@ impl Iterator for DocumentsIdsIter<'_> {
 }
 
 pub struct AllDocumentsFieldsCountsIter<'txn> {
-    iter: zlmdb::RoIter<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
+    iter: heed::RoIter<'txn, OwnedType<DocumentAttrKey>, OwnedType<u64>>,
 }
 
 impl<'r> Iterator for AllDocumentsFieldsCountsIter<'r> {
diff --git a/meilidb-core/src/store/main.rs b/meilidb-core/src/store/main.rs
index 6e99ac067..416fcfe37 100644
--- a/meilidb-core/src/store/main.rs
+++ b/meilidb-core/src/store/main.rs
@@ -1,8 +1,8 @@
 use crate::RankedMap;
+use heed::types::{ByteSlice, OwnedType, SerdeBincode, Str};
+use heed::Result as ZResult;
 use meilidb_schema::Schema;
 use std::sync::Arc;
-use zlmdb::types::{ByteSlice, OwnedType, Serde, Str};
-use zlmdb::Result as ZResult;
 
 const CUSTOMS_KEY: &str = "customs-key";
 const NUMBER_OF_DOCUMENTS_KEY: &str = "number-of-documents";
@@ -13,16 +13,16 @@ const WORDS_KEY: &str = "words";
 
 #[derive(Copy, Clone)]
 pub struct Main {
-    pub(crate) main: zlmdb::DynDatabase,
+    pub(crate) main: heed::PolyDatabase,
 }
 
 impl Main {
-    pub fn put_words_fst(self, writer: &mut zlmdb::RwTxn, fst: &fst::Set) -> ZResult<()> {
+    pub fn put_words_fst(self, writer: &mut heed::RwTxn, fst: &fst::Set) -> ZResult<()> {
         let bytes = fst.as_fst().as_bytes();
         self.main.put::<Str, ByteSlice>(writer, WORDS_KEY, bytes)
     }
 
-    pub fn words_fst(self, reader: &zlmdb::RoTxn) -> ZResult<Option<fst::Set>> {
+    pub fn words_fst(self, reader: &heed::RoTxn) -> ZResult<Option<fst::Set>> {
         match self.main.get::<Str, ByteSlice>(reader, WORDS_KEY)? {
             Some(bytes) => {
                 let len = bytes.len();
@@ -34,31 +34,32 @@ impl Main {
         }
     }
 
-    pub fn put_schema(self, writer: &mut zlmdb::RwTxn, schema: &Schema) -> ZResult<()> {
+    pub fn put_schema(self, writer: &mut heed::RwTxn, schema: &Schema) -> ZResult<()> {
         self.main
-            .put::<Str, Serde<Schema>>(writer, SCHEMA_KEY, schema)
+            .put::<Str, SerdeBincode<Schema>>(writer, SCHEMA_KEY, schema)
     }
 
-    pub fn schema(self, reader: &zlmdb::RoTxn) -> ZResult<Option<Schema>> {
-        self.main.get::<Str, Serde<Schema>>(reader, SCHEMA_KEY)
-    }
-
-    pub fn put_ranked_map(self, writer: &mut zlmdb::RwTxn, ranked_map: &RankedMap) -> ZResult<()> {
+    pub fn schema(self, reader: &heed::RoTxn) -> ZResult<Option<Schema>> {
         self.main
-            .put::<Str, Serde<RankedMap>>(writer, RANKED_MAP_KEY, &ranked_map)
+            .get::<Str, SerdeBincode<Schema>>(reader, SCHEMA_KEY)
     }
 
-    pub fn ranked_map(self, reader: &zlmdb::RoTxn) -> ZResult<Option<RankedMap>> {
+    pub fn put_ranked_map(self, writer: &mut heed::RwTxn, ranked_map: &RankedMap) -> ZResult<()> {
         self.main
-            .get::<Str, Serde<RankedMap>>(reader, RANKED_MAP_KEY)
+            .put::<Str, SerdeBincode<RankedMap>>(writer, RANKED_MAP_KEY, &ranked_map)
     }
 
-    pub fn put_synonyms_fst(self, writer: &mut zlmdb::RwTxn, fst: &fst::Set) -> ZResult<()> {
+    pub fn ranked_map(self, reader: &heed::RoTxn) -> ZResult<Option<RankedMap>> {
+        self.main
+            .get::<Str, SerdeBincode<RankedMap>>(reader, RANKED_MAP_KEY)
+    }
+
+    pub fn put_synonyms_fst(self, writer: &mut heed::RwTxn, fst: &fst::Set) -> ZResult<()> {
         let bytes = fst.as_fst().as_bytes();
         self.main.put::<Str, ByteSlice>(writer, SYNONYMS_KEY, bytes)
     }
 
-    pub fn synonyms_fst(self, reader: &zlmdb::RoTxn) -> ZResult<Option<fst::Set>> {
+    pub fn synonyms_fst(self, reader: &heed::RoTxn) -> ZResult<Option<fst::Set>> {
         match self.main.get::<Str, ByteSlice>(reader, SYNONYMS_KEY)? {
             Some(bytes) => {
                 let len = bytes.len();
@@ -70,7 +71,7 @@ impl Main {
         }
     }
 
-    pub fn put_number_of_documents<F>(self, writer: &mut zlmdb::RwTxn, f: F) -> ZResult<u64>
+    pub fn put_number_of_documents<F>(self, writer: &mut heed::RwTxn, f: F) -> ZResult<u64>
     where
         F: Fn(u64) -> u64,
     {
@@ -80,7 +81,7 @@ impl Main {
         Ok(new)
     }
 
-    pub fn number_of_documents(self, reader: &zlmdb::RoTxn) -> ZResult<u64> {
+    pub fn number_of_documents(self, reader: &heed::RoTxn) -> ZResult<u64> {
         match self
             .main
             .get::<Str, OwnedType<u64>>(reader, NUMBER_OF_DOCUMENTS_KEY)?
@@ -90,12 +91,12 @@ impl Main {
         }
     }
 
-    pub fn put_customs(self, writer: &mut zlmdb::RwTxn, customs: &[u8]) -> ZResult<()> {
+    pub fn put_customs(self, writer: &mut heed::RwTxn, customs: &[u8]) -> ZResult<()> {
         self.main
             .put::<Str, ByteSlice>(writer, CUSTOMS_KEY, customs)
     }
 
-    pub fn customs<'txn>(self, reader: &'txn zlmdb::RoTxn) -> ZResult<Option<&'txn [u8]>> {
+    pub fn customs<'txn>(self, reader: &'txn heed::RoTxn) -> ZResult<Option<&'txn [u8]>> {
         self.main.get::<Str, ByteSlice>(reader, CUSTOMS_KEY)
     }
 }
diff --git a/meilidb-core/src/store/mod.rs b/meilidb-core/src/store/mod.rs
index 68170e64e..ad14d46c5 100644
--- a/meilidb-core/src/store/mod.rs
+++ b/meilidb-core/src/store/mod.rs
@@ -20,10 +20,10 @@ pub use self::updates_results::UpdatesResults;
 
 use std::collections::HashSet;
 
+use heed::Result as ZResult;
 use meilidb_schema::{Schema, SchemaAttr};
 use serde::de;
 use zerocopy::{AsBytes, FromBytes};
-use zlmdb::Result as ZResult;
 
 use crate::criterion::Criteria;
 use crate::serde::Deserializer;
@@ -97,7 +97,7 @@ pub struct Index {
 impl Index {
     pub fn document<T: de::DeserializeOwned>(
         &self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         attributes: Option<&HashSet<&str>>,
         document_id: DocumentId,
     ) -> MResult<Option<T>> {
@@ -127,7 +127,7 @@ impl Index {
 
     pub fn document_attribute<T: de::DeserializeOwned>(
         &self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         document_id: DocumentId,
         attribute: SchemaAttr,
     ) -> MResult<Option<T>> {
@@ -140,12 +140,12 @@ impl Index {
         }
     }
 
-    pub fn schema_update(&self, writer: &mut zlmdb::RwTxn, schema: Schema) -> MResult<u64> {
+    pub fn schema_update(&self, writer: &mut heed::RwTxn, schema: Schema) -> MResult<u64> {
         let _ = self.updates_notifier.send(());
         update::push_schema_update(writer, self.updates, self.updates_results, schema)
     }
 
-    pub fn customs_update(&self, writer: &mut zlmdb::RwTxn, customs: Vec<u8>) -> ZResult<u64> {
+    pub fn customs_update(&self, writer: &mut heed::RwTxn, customs: Vec<u8>) -> ZResult<u64> {
         let _ = self.updates_notifier.send(());
         update::push_customs_update(writer, self.updates, self.updates_results, customs)
     }
@@ -182,7 +182,7 @@ impl Index {
         )
     }
 
-    pub fn current_update_id(&self, reader: &zlmdb::RoTxn) -> MResult<Option<u64>> {
+    pub fn current_update_id(&self, reader: &heed::RoTxn) -> MResult<Option<u64>> {
         match self.updates.last_update_id(reader)? {
             Some((id, _)) => Ok(Some(id)),
             None => Ok(None),
@@ -191,7 +191,7 @@ impl Index {
 
     pub fn update_status(
         &self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         update_id: u64,
     ) -> MResult<update::UpdateStatus> {
         update::update_status(reader, self.updates, self.updates_results, update_id)
@@ -221,7 +221,7 @@ impl Index {
 }
 
 pub fn create(
-    env: &zlmdb::Env,
+    env: &heed::Env,
     name: &str,
     updates_notifier: crossbeam_channel::Sender<()>,
 ) -> MResult<Index> {
@@ -261,7 +261,7 @@ pub fn create(
 }
 
 pub fn open(
-    env: &zlmdb::Env,
+    env: &heed::Env,
     name: &str,
     updates_notifier: crossbeam_channel::Sender<()>,
 ) -> MResult<Option<Index>> {
diff --git a/meilidb-core/src/store/postings_lists.rs b/meilidb-core/src/store/postings_lists.rs
index 8835a504a..8f8bc919e 100644
--- a/meilidb-core/src/store/postings_lists.rs
+++ b/meilidb-core/src/store/postings_lists.rs
@@ -1,31 +1,31 @@
 use crate::DocIndex;
+use heed::types::{ByteSlice, CowSlice};
+use heed::Result as ZResult;
 use sdset::{Set, SetBuf};
 use std::borrow::Cow;
-use zlmdb::types::{ByteSlice, CowSlice};
-use zlmdb::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct PostingsLists {
-    pub(crate) postings_lists: zlmdb::Database<ByteSlice, CowSlice<DocIndex>>,
+    pub(crate) postings_lists: heed::Database<ByteSlice, CowSlice<DocIndex>>,
 }
 
 impl PostingsLists {
     pub fn put_postings_list(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         word: &[u8],
         words_indexes: &Set<DocIndex>,
     ) -> ZResult<()> {
         self.postings_lists.put(writer, word, words_indexes)
     }
 
-    pub fn del_postings_list(self, writer: &mut zlmdb::RwTxn, word: &[u8]) -> ZResult<bool> {
+    pub fn del_postings_list(self, writer: &mut heed::RwTxn, word: &[u8]) -> ZResult<bool> {
         self.postings_lists.delete(writer, word)
     }
 
     pub fn postings_list<'txn>(
         self,
-        reader: &'txn zlmdb::RoTxn,
+        reader: &'txn heed::RoTxn,
         word: &[u8],
     ) -> ZResult<Option<Cow<'txn, Set<DocIndex>>>> {
         match self.postings_lists.get(reader, word)? {
diff --git a/meilidb-core/src/store/synonyms.rs b/meilidb-core/src/store/synonyms.rs
index b8002d464..80b8bba67 100644
--- a/meilidb-core/src/store/synonyms.rs
+++ b/meilidb-core/src/store/synonyms.rs
@@ -1,16 +1,16 @@
+use heed::types::ByteSlice;
+use heed::Result as ZResult;
 use std::sync::Arc;
-use zlmdb::types::ByteSlice;
-use zlmdb::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct Synonyms {
-    pub(crate) synonyms: zlmdb::Database<ByteSlice, ByteSlice>,
+    pub(crate) synonyms: heed::Database<ByteSlice, ByteSlice>,
 }
 
 impl Synonyms {
     pub fn put_synonyms(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         word: &[u8],
         synonyms: &fst::Set,
     ) -> ZResult<()> {
@@ -18,11 +18,11 @@ impl Synonyms {
         self.synonyms.put(writer, word, bytes)
     }
 
-    pub fn del_synonyms(self, writer: &mut zlmdb::RwTxn, word: &[u8]) -> ZResult<bool> {
+    pub fn del_synonyms(self, writer: &mut heed::RwTxn, word: &[u8]) -> ZResult<bool> {
         self.synonyms.delete(writer, word)
     }
 
-    pub fn synonyms(self, reader: &zlmdb::RoTxn, word: &[u8]) -> ZResult<Option<fst::Set>> {
+    pub fn synonyms(self, reader: &heed::RoTxn, word: &[u8]) -> ZResult<Option<fst::Set>> {
         match self.synonyms.get(reader, word)? {
             Some(bytes) => {
                 let len = bytes.len();
diff --git a/meilidb-core/src/store/updates.rs b/meilidb-core/src/store/updates.rs
index 8afe95e0d..e4e634dcd 100644
--- a/meilidb-core/src/store/updates.rs
+++ b/meilidb-core/src/store/updates.rs
@@ -1,42 +1,16 @@
 use super::BEU64;
 use crate::update::Update;
-use serde::{Deserialize, Serialize};
-use std::borrow::Cow;
-use zlmdb::types::OwnedType;
-use zlmdb::{BytesDecode, BytesEncode, Result as ZResult};
-
-pub struct SerdeJson<T>(std::marker::PhantomData<T>);
-
-impl<T> BytesEncode for SerdeJson<T>
-where
-    T: Serialize,
-{
-    type EItem = T;
-
-    fn bytes_encode(item: &Self::EItem) -> Option<Cow<[u8]>> {
-        serde_json::to_vec(item).map(Cow::Owned).ok()
-    }
-}
-
-impl<'a, T: 'a> BytesDecode<'a> for SerdeJson<T>
-where
-    T: Deserialize<'a> + Clone,
-{
-    type DItem = T;
-
-    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
-        serde_json::from_slice(bytes).ok()
-    }
-}
+use heed::types::{OwnedType, SerdeJson};
+use heed::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct Updates {
-    pub(crate) updates: zlmdb::Database<OwnedType<BEU64>, SerdeJson<Update>>,
+    pub(crate) updates: heed::Database<OwnedType<BEU64>, SerdeJson<Update>>,
 }
 
 impl Updates {
     // TODO do not trigger deserialize if possible
-    pub fn last_update_id(self, reader: &zlmdb::RoTxn) -> ZResult<Option<(u64, Update)>> {
+    pub fn last_update_id(self, reader: &heed::RoTxn) -> ZResult<Option<(u64, Update)>> {
         match self.updates.last(reader)? {
             Some((key, data)) => Ok(Some((key.get(), data))),
             None => Ok(None),
@@ -44,7 +18,7 @@ impl Updates {
     }
 
     // TODO do not trigger deserialize if possible
-    fn first_update_id(self, reader: &zlmdb::RoTxn) -> ZResult<Option<(u64, Update)>> {
+    fn first_update_id(self, reader: &heed::RoTxn) -> ZResult<Option<(u64, Update)>> {
         match self.updates.first(reader)? {
             Some((key, data)) => Ok(Some((key.get(), data))),
             None => Ok(None),
@@ -52,14 +26,14 @@ impl Updates {
     }
 
     // TODO do not trigger deserialize if possible
-    pub fn contains(self, reader: &zlmdb::RoTxn, update_id: u64) -> ZResult<bool> {
+    pub fn contains(self, reader: &heed::RoTxn, update_id: u64) -> ZResult<bool> {
         let update_id = BEU64::new(update_id);
         self.updates.get(reader, &update_id).map(|v| v.is_some())
     }
 
     pub fn put_update(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         update_id: u64,
         update: &Update,
     ) -> ZResult<()> {
@@ -68,7 +42,7 @@ impl Updates {
         self.updates.put(writer, &update_id, update)
     }
 
-    pub fn pop_front(self, writer: &mut zlmdb::RwTxn) -> ZResult<Option<(u64, Update)>> {
+    pub fn pop_front(self, writer: &mut heed::RwTxn) -> ZResult<Option<(u64, Update)>> {
         match self.first_update_id(writer)? {
             Some((update_id, update)) => {
                 let key = BEU64::new(update_id);
diff --git a/meilidb-core/src/store/updates_results.rs b/meilidb-core/src/store/updates_results.rs
index cd3c96075..51db65cc1 100644
--- a/meilidb-core/src/store/updates_results.rs
+++ b/meilidb-core/src/store/updates_results.rs
@@ -1,15 +1,15 @@
 use super::BEU64;
 use crate::update::UpdateResult;
-use zlmdb::types::{OwnedType, Serde};
-use zlmdb::Result as ZResult;
+use heed::types::{OwnedType, SerdeBincode};
+use heed::Result as ZResult;
 
 #[derive(Copy, Clone)]
 pub struct UpdatesResults {
-    pub(crate) updates_results: zlmdb::Database<OwnedType<BEU64>, Serde<UpdateResult>>,
+    pub(crate) updates_results: heed::Database<OwnedType<BEU64>, SerdeBincode<UpdateResult>>,
 }
 
 impl UpdatesResults {
-    pub fn last_update_id(self, reader: &zlmdb::RoTxn) -> ZResult<Option<(u64, UpdateResult)>> {
+    pub fn last_update_id(self, reader: &heed::RoTxn) -> ZResult<Option<(u64, UpdateResult)>> {
         match self.updates_results.last(reader)? {
             Some((key, data)) => Ok(Some((key.get(), data))),
             None => Ok(None),
@@ -18,7 +18,7 @@ impl UpdatesResults {
 
     pub fn put_update_result(
         self,
-        writer: &mut zlmdb::RwTxn,
+        writer: &mut heed::RwTxn,
         update_id: u64,
         update_result: &UpdateResult,
     ) -> ZResult<()> {
@@ -28,7 +28,7 @@ impl UpdatesResults {
 
     pub fn update_result(
         self,
-        reader: &zlmdb::RoTxn,
+        reader: &heed::RoTxn,
         update_id: u64,
     ) -> ZResult<Option<UpdateResult>> {
         let update_id = BEU64::new(update_id);
diff --git a/meilidb-core/src/update/customs_update.rs b/meilidb-core/src/update/customs_update.rs
index 5072dc096..72ecfba71 100644
--- a/meilidb-core/src/update/customs_update.rs
+++ b/meilidb-core/src/update/customs_update.rs
@@ -1,9 +1,9 @@
 use crate::store;
 use crate::update::{next_update_id, Update};
-use zlmdb::Result as ZResult;
+use heed::Result as ZResult;
 
 pub fn apply_customs_update(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     customs: &[u8],
 ) -> ZResult<()> {
@@ -11,7 +11,7 @@ pub fn apply_customs_update(
 }
 
 pub fn push_customs_update(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     customs: Vec<u8>,
diff --git a/meilidb-core/src/update/documents_addition.rs b/meilidb-core/src/update/documents_addition.rs
index 22769fbe2..656dcba5b 100644
--- a/meilidb-core/src/update/documents_addition.rs
+++ b/meilidb-core/src/update/documents_addition.rs
@@ -35,7 +35,7 @@ impl<D> DocumentsAddition<D> {
         self.documents.push(document);
     }
 
-    pub fn finalize(self, writer: &mut zlmdb::RwTxn) -> MResult<u64>
+    pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64>
     where
         D: serde::Serialize,
     {
@@ -57,7 +57,7 @@ impl<D> Extend<D> for DocumentsAddition<D> {
 }
 
 pub fn push_documents_addition<D: serde::Serialize>(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     addition: Vec<D>,
@@ -78,7 +78,7 @@ pub fn push_documents_addition<D: serde::Serialize>(
 }
 
 pub fn apply_documents_addition(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     documents_fields_store: store::DocumentsFields,
     documents_fields_counts_store: store::DocumentsFieldsCounts,
diff --git a/meilidb-core/src/update/documents_deletion.rs b/meilidb-core/src/update/documents_deletion.rs
index e640cb508..e1ec71ddc 100644
--- a/meilidb-core/src/update/documents_deletion.rs
+++ b/meilidb-core/src/update/documents_deletion.rs
@@ -49,7 +49,7 @@ impl DocumentsDeletion {
         Ok(())
     }
 
-    pub fn finalize(self, writer: &mut zlmdb::RwTxn) -> MResult<u64> {
+    pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
         let _ = self.updates_notifier.send(());
         let update_id = push_documents_deletion(
             writer,
@@ -68,7 +68,7 @@ impl Extend<DocumentId> for DocumentsDeletion {
 }
 
 pub fn push_documents_deletion(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     deletion: Vec<DocumentId>,
@@ -82,7 +82,7 @@ pub fn push_documents_deletion(
 }
 
 pub fn apply_documents_deletion(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     documents_fields_store: store::DocumentsFields,
     documents_fields_counts_store: store::DocumentsFieldsCounts,
diff --git a/meilidb-core/src/update/mod.rs b/meilidb-core/src/update/mod.rs
index ea93413f1..8958074ec 100644
--- a/meilidb-core/src/update/mod.rs
+++ b/meilidb-core/src/update/mod.rs
@@ -16,9 +16,9 @@ use std::cmp;
 use std::collections::BTreeMap;
 use std::time::{Duration, Instant};
 
+use heed::Result as ZResult;
 use log::debug;
 use serde::{Deserialize, Serialize};
-use zlmdb::Result as ZResult;
 
 use crate::{store, DocumentId, MResult, RankedMap};
 use meilidb_schema::Schema;
@@ -64,7 +64,7 @@ pub enum UpdateStatus {
 }
 
 pub fn update_status(
-    reader: &zlmdb::RoTxn,
+    reader: &heed::RoTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     update_id: u64,
@@ -82,7 +82,7 @@ pub fn update_status(
 }
 
 pub fn next_update_id(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
 ) -> ZResult<u64> {
@@ -98,10 +98,7 @@ pub fn next_update_id(
     Ok(new_update_id)
 }
 
-pub fn update_task(
-    writer: &mut zlmdb::RwTxn,
-    index: store::Index,
-) -> MResult<Option<UpdateResult>> {
+pub fn update_task(writer: &mut heed::RwTxn, index: store::Index) -> MResult<Option<UpdateResult>> {
     let (update_id, update) = match index.updates.pop_front(writer)? {
         Some(value) => value,
         None => return Ok(None),
diff --git a/meilidb-core/src/update/schema_update.rs b/meilidb-core/src/update/schema_update.rs
index 652ca06dd..b36370eda 100644
--- a/meilidb-core/src/update/schema_update.rs
+++ b/meilidb-core/src/update/schema_update.rs
@@ -3,7 +3,7 @@ use crate::{error::UnsupportedOperation, store, MResult};
 use meilidb_schema::Schema;
 
 pub fn apply_schema_update(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     new_schema: &Schema,
 ) -> MResult<()> {
@@ -17,7 +17,7 @@ pub fn apply_schema_update(
 }
 
 pub fn push_schema_update(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     schema: Schema,
diff --git a/meilidb-core/src/update/synonyms_addition.rs b/meilidb-core/src/update/synonyms_addition.rs
index f32475a1e..656e5e727 100644
--- a/meilidb-core/src/update/synonyms_addition.rs
+++ b/meilidb-core/src/update/synonyms_addition.rs
@@ -42,7 +42,7 @@ impl SynonymsAddition {
             .extend(alternatives);
     }
 
-    pub fn finalize(self, writer: &mut zlmdb::RwTxn) -> MResult<u64> {
+    pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
         let _ = self.updates_notifier.send(());
         let update_id = push_synonyms_addition(
             writer,
@@ -55,7 +55,7 @@ impl SynonymsAddition {
 }
 
 pub fn push_synonyms_addition(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     addition: BTreeMap<String, Vec<String>>,
@@ -69,7 +69,7 @@ pub fn push_synonyms_addition(
 }
 
 pub fn apply_synonyms_addition(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     synonyms_store: store::Synonyms,
     addition: BTreeMap<String, Vec<String>>,
diff --git a/meilidb-core/src/update/synonyms_deletion.rs b/meilidb-core/src/update/synonyms_deletion.rs
index c498c3ab0..b76f3f761 100644
--- a/meilidb-core/src/update/synonyms_deletion.rs
+++ b/meilidb-core/src/update/synonyms_deletion.rs
@@ -49,7 +49,7 @@ impl SynonymsDeletion {
         }
     }
 
-    pub fn finalize(self, writer: &mut zlmdb::RwTxn) -> MResult<u64> {
+    pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
         let _ = self.updates_notifier.send(());
         let update_id = push_synonyms_deletion(
             writer,
@@ -62,7 +62,7 @@ impl SynonymsDeletion {
 }
 
 pub fn push_synonyms_deletion(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
     deletion: BTreeMap<String, Option<Vec<String>>>,
@@ -76,7 +76,7 @@ pub fn push_synonyms_deletion(
 }
 
 pub fn apply_synonyms_deletion(
-    writer: &mut zlmdb::RwTxn,
+    writer: &mut heed::RwTxn,
     main_store: store::Main,
     synonyms_store: store::Synonyms,
     deletion: BTreeMap<String, Option<Vec<String>>>,