diff --git a/datasets/movies/settings.json b/datasets/movies/settings.json
index 66eeedba6..0edefd7d0 100644
--- a/datasets/movies/settings.json
+++ b/datasets/movies/settings.json
@@ -1,7 +1,7 @@
 {
     "identifier": "id",
-    "searchable_attributes": ["title", "overview"],
-    "displayed_attributes": [
+    "searchableAttributes": ["title", "overview"],
+    "displayedAttributes": [
         "id",
         "title",
         "overview",
diff --git a/meilisearch-core/src/bucket_sort.rs b/meilisearch-core/src/bucket_sort.rs
index 8b2c7ebe5..4c34f1abd 100644
--- a/meilisearch-core/src/bucket_sort.rs
+++ b/meilisearch-core/src/bucket_sort.rs
@@ -172,7 +172,6 @@ where
 
     debug!("bucket sort took {:.02?}", before_bucket_sort.elapsed());
 
-
     Ok(documents)
 }
 
diff --git a/meilisearch-core/src/error.rs b/meilisearch-core/src/error.rs
index c65f198e7..862c517a0 100644
--- a/meilisearch-core/src/error.rs
+++ b/meilisearch-core/src/error.rs
@@ -87,12 +87,12 @@ impl fmt::Display for Error {
         match self {
             Io(e) => write!(f, "{}", e),
             IndexAlreadyExists => write!(f, "index already exists"),
-            MissingIdentifier => write!(f, "schema cannot be build without identifier"),
+            MissingIdentifier => write!(f, "schema cannot be built without identifier"),
             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"),
-            MaxFieldsLimitExceeded => write!(f, "maximum field in a document is exceeded"),
-            Schema(e) => write!(f, "schemas error; {}", e),
+            MaxFieldsLimitExceeded => write!(f, "maximum number of fields in a document exceeded"),
+            Schema(e) => write!(f, "schema error; {}", e),
             Zlmdb(e) => write!(f, "heed error; {}", e),
             Fst(e) => write!(f, "fst error; {}", e),
             SerdeJson(e) => write!(f, "serde json error; {}", e),
diff --git a/meilisearch-core/src/query_builder.rs b/meilisearch-core/src/query_builder.rs
index f3a3f462b..5bde93665 100644
--- a/meilisearch-core/src/query_builder.rs
+++ b/meilisearch-core/src/query_builder.rs
@@ -275,7 +275,7 @@ mod tests {
                 let mut final_indexes = Vec::new();
                 for index in indexes {
                     let name = index.attribute.to_string();
-                    schema.get_or_create_empty(&name).unwrap();
+                    schema.insert(&name).unwrap();
                     let indexed_pos = schema.set_indexed(&name).unwrap().1;
                     let index = DocIndex {
                         attribute: indexed_pos.0,
diff --git a/meilisearch-core/src/serde/serializer.rs b/meilisearch-core/src/serde/serializer.rs
index 2b38e0aeb..20e26886d 100644
--- a/meilisearch-core/src/serde/serializer.rs
+++ b/meilisearch-core/src/serde/serializer.rs
@@ -235,7 +235,7 @@ impl<'a, 'b> ser::SerializeMap for MapSerializer<'a, 'b> {
         let key = key.serialize(ConvertToString)?;
         serialize_value(
             self.txn,
-            key,
+            key.as_str(),
             self.schema,
             self.document_id,
             self.document_store,
@@ -275,7 +275,7 @@ impl<'a, 'b> ser::SerializeStruct for StructSerializer<'a, 'b> {
     {
         serialize_value(
             self.txn,
-            key.to_string(),
+            key,
             self.schema,
             self.document_id,
             self.document_store,
@@ -293,7 +293,7 @@ impl<'a, 'b> ser::SerializeStruct for StructSerializer<'a, 'b> {
 
 pub fn serialize_value<'a, T: ?Sized>(
     txn: &mut heed::RwTxn<MainT>,
-    attribute: String,
+    attribute: &str,
     schema: &'a mut Schema,
     document_id: DocumentId,
     document_store: DocumentsFields,
@@ -305,7 +305,7 @@ pub fn serialize_value<'a, T: ?Sized>(
 where
     T: ser::Serialize,
 {
-    let field_id = schema.get_or_create(&attribute)?;
+    let field_id = schema.insert_and_index(&attribute)?;
     serialize_value_with_id(
         txn,
         field_id,
diff --git a/meilisearch-core/src/settings.rs b/meilisearch-core/src/settings.rs
index 551c44cf1..e895a5eee 100644
--- a/meilisearch-core/src/settings.rs
+++ b/meilisearch-core/src/settings.rs
@@ -1,5 +1,6 @@
 use std::collections::{BTreeMap, BTreeSet, HashSet};
 use std::str::FromStr;
+use std::iter::IntoIterator;
 
 use serde::{Deserialize, Deserializer, Serialize};
 use once_cell::sync::Lazy;
@@ -17,8 +18,6 @@ pub struct Settings {
     #[serde(default, deserialize_with = "deserialize_some")]
     pub ranking_distinct: Option<Option<String>>,
     #[serde(default, deserialize_with = "deserialize_some")]
-    pub identifier: Option<Option<String>>,
-    #[serde(default, deserialize_with = "deserialize_some")]
     pub searchable_attributes: Option<Option<Vec<String>>>,
     #[serde(default, deserialize_with = "deserialize_some")]
     pub displayed_attributes: Option<Option<HashSet<String>>>,
@@ -43,7 +42,7 @@ impl Settings {
         let settings = self.clone();
 
         let ranking_rules = match settings.ranking_rules {
-            Some(Some(rules)) => UpdateState::Update(RankingRule::from_vec(rules.iter().map(|m| m.as_ref()).collect())?),
+            Some(Some(rules)) => UpdateState::Update(RankingRule::from_iter(rules.iter())?),
             Some(None) => UpdateState::Clear,
             None => UpdateState::Nothing,
         };
@@ -51,7 +50,7 @@ impl Settings {
         Ok(SettingsUpdate {
             ranking_rules,
             ranking_distinct: settings.ranking_distinct.into(),
-            identifier: settings.identifier.into(),
+            identifier: UpdateState::Nothing,
             searchable_attributes: settings.searchable_attributes.into(),
             displayed_attributes: settings.displayed_attributes.into(),
             stop_words: settings.stop_words.into(),
@@ -139,16 +138,16 @@ impl FromStr for RankingRule {
 }
 
 impl RankingRule {
-    pub fn get_field(&self) -> Option<&str> {
+    pub fn field(&self) -> Option<&str> {
         match self {
             RankingRule::Asc(field) | RankingRule::Dsc(field) => Some(field),
             _ => None,
         }
     }
 
-    pub fn from_vec(rules: Vec<&str>) -> Result<Vec<RankingRule>, RankingRuleConversionError> {
-        rules.iter()
-            .map(|s| RankingRule::from_str(s))
+    pub fn from_iter(rules: impl IntoIterator<Item = impl AsRef<str>>) -> Result<Vec<RankingRule>, RankingRuleConversionError> {
+        rules.into_iter()
+            .map(|s| RankingRule::from_str(s.as_ref()))
             .collect()
     }
 }
diff --git a/meilisearch-core/src/store/main.rs b/meilisearch-core/src/store/main.rs
index 1aa3d5d2a..2e13d52ec 100644
--- a/meilisearch-core/src/store/main.rs
+++ b/meilisearch-core/src/store/main.rs
@@ -192,8 +192,8 @@ impl Main {
         self.main.get::<_, Str, SerdeBincode<Vec<RankingRule>>>(reader, RANKING_RULES_KEY)
     }
 
-    pub fn put_ranking_rules(self, writer: &mut heed::RwTxn<MainT>, value: Vec<RankingRule>) -> ZResult<()> {
-        self.main.put::<_, Str, SerdeBincode<Vec<RankingRule>>>(writer, RANKING_RULES_KEY, &value)
+    pub fn put_ranking_rules(self, writer: &mut heed::RwTxn<MainT>, value: &[RankingRule]) -> ZResult<()> {
+        self.main.put::<_, Str, SerdeBincode<Vec<RankingRule>>>(writer, RANKING_RULES_KEY, &value.to_vec())
     }
 
     pub fn delete_ranking_rules(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<bool> {
@@ -201,11 +201,14 @@ impl Main {
     }
 
     pub fn ranking_distinct(&self, reader: &heed::RoTxn<MainT>) -> ZResult<Option<String>> {
-        self.main.get::<_, Str, SerdeBincode<String>>(reader, RANKING_DISTINCT_KEY)
+        if let Some(value) = self.main.get::<_, Str, Str>(reader, RANKING_DISTINCT_KEY)? {
+            return Ok(Some(value.to_owned()))
+        }
+        return Ok(None)
     }
 
-    pub fn put_ranking_distinct(self, writer: &mut heed::RwTxn<MainT>, value: String) -> ZResult<()> {
-        self.main.put::<_, Str, SerdeBincode<String>>(writer, RANKING_DISTINCT_KEY, &value)
+    pub fn put_ranking_distinct(self, writer: &mut heed::RwTxn<MainT>, value: &str) -> ZResult<()> {
+        self.main.put::<_, Str, Str>(writer, RANKING_DISTINCT_KEY, value)
     }
 
     pub fn delete_ranking_distinct(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<bool> {
diff --git a/meilisearch-core/src/update/documents_deletion.rs b/meilisearch-core/src/update/documents_deletion.rs
index 9152c4e5b..314632db3 100644
--- a/meilisearch-core/src/update/documents_deletion.rs
+++ b/meilisearch-core/src/update/documents_deletion.rs
@@ -106,7 +106,7 @@ pub fn apply_documents_deletion(
     let mut words_document_ids = HashMap::new();
     for id in idset {
         // remove all the ranked attributes from the ranked_map
-        for ranked_attr in &ranked_fields {
+        for ranked_attr in ranked_fields {
             ranked_map.remove(id, *ranked_attr);
         }
 
diff --git a/meilisearch-core/src/update/settings_update.rs b/meilisearch-core/src/update/settings_update.rs
index ed75b0cf1..4482d52eb 100644
--- a/meilisearch-core/src/update/settings_update.rs
+++ b/meilisearch-core/src/update/settings_update.rs
@@ -44,9 +44,9 @@ pub fn apply_settings_update(
 
     match settings.ranking_rules {
         UpdateState::Update(v) => {
-            let ranked_field: Vec<&str> = v.iter().filter_map(RankingRule::get_field).collect();
+            let ranked_field: Vec<&str> = v.iter().filter_map(RankingRule::field).collect();
             schema.update_ranked(ranked_field)?;
-            index.main.put_ranking_rules(writer, v)?;
+            index.main.put_ranking_rules(writer, &v)?;
             must_reindex = true;
         },
         UpdateState::Clear => {
@@ -60,7 +60,7 @@ pub fn apply_settings_update(
 
     match settings.ranking_distinct {
         UpdateState::Update(v) => {
-            index.main.put_ranking_distinct(writer, v)?;
+            index.main.put_ranking_distinct(writer, &v)?;
         },
         UpdateState::Clear => {
             index.main.delete_ranking_distinct(writer)?;
@@ -99,16 +99,12 @@ pub fn apply_settings_update(
         UpdateState::Nothing => (),
     };
 
-    match settings.identifier.clone() {
-        UpdateState::Update(v) => {
-            schema.set_identifier(v.as_ref())?;
-            index.main.put_schema(writer, &schema)?;
-            must_reindex = true;
-        },
-        _ => {
-            index.main.put_schema(writer, &schema)?;
-        },
-    };
+    if let UpdateState::Update(v) = settings.identifier.clone() {
+        schema.set_identifier(v.as_ref())?;
+        must_reindex = true;
+    }
+
+    index.main.put_schema(writer, &schema)?;
 
     match settings.stop_words {
         UpdateState::Update(stop_words) => {
@@ -121,13 +117,13 @@ pub fn apply_settings_update(
                 must_reindex = true;
             }
         },
-        _ => (),
+        UpdateState::Nothing => (),
     }
 
     match settings.synonyms {
         UpdateState::Update(synonyms) => apply_synonyms_update(writer, index, synonyms)?,
         UpdateState::Clear => apply_synonyms_update(writer, index, BTreeMap::new())?,
-        _ => (),
+        UpdateState::Nothing => (),
     }
 
     if must_reindex {
diff --git a/meilisearch-http/.DS_Store b/meilisearch-http/.DS_Store
deleted file mode 100644
index 81fb6f831..000000000
Binary files a/meilisearch-http/.DS_Store and /dev/null differ
diff --git a/meilisearch-http/src/data.rs b/meilisearch-http/src/data.rs
index 7e5c92348..1d0e14c9a 100644
--- a/meilisearch-http/src/data.rs
+++ b/meilisearch-http/src/data.rs
@@ -92,7 +92,13 @@ impl DataInner {
         // convert attributes to their names
         let frequency: HashMap<_, _> = fields_frequency
             .into_iter()
-            .map(|(a, c)| (schema.name(a).unwrap().to_string(), c))
+            .filter_map(|(a, c)| {
+                if let Some(name) = schema.name(a) {
+                    return Some((name.to_string(), c));
+                } else {
+                    return None;
+                }
+            })
             .collect();
 
         index
diff --git a/meilisearch-http/src/error.rs b/meilisearch-http/src/error.rs
index 0ca377576..a2b539687 100644
--- a/meilisearch-http/src/error.rs
+++ b/meilisearch-http/src/error.rs
@@ -2,10 +2,10 @@ use std::fmt::Display;
 
 use http::status::StatusCode;
 use log::{error, warn};
+use meilisearch_core::{FstError, HeedError};
 use serde::{Deserialize, Serialize};
 use tide::IntoResponse;
 use tide::Response;
-use meilisearch_core::{HeedError, FstError};
 
 use crate::helpers::meilisearch::Error as SearchError;
 
diff --git a/meilisearch-http/src/helpers/meilisearch.rs b/meilisearch-http/src/helpers/meilisearch.rs
index db1ea3709..c15124d07 100644
--- a/meilisearch-http/src/helpers/meilisearch.rs
+++ b/meilisearch-http/src/helpers/meilisearch.rs
@@ -206,7 +206,8 @@ impl<'a> SearchBuilder<'a> {
         query_builder.with_fetch_timeout(self.timeout);
 
         let start = Instant::now();
-        let docs = query_builder.query(reader, &self.query, self.offset..(self.offset + self.limit));
+        let docs =
+            query_builder.query(reader, &self.query, self.offset..(self.offset + self.limit));
         let time_ms = start.elapsed().as_millis() as usize;
 
         let mut hits = Vec::with_capacity(self.limit);
diff --git a/meilisearch-http/src/routes/mod.rs b/meilisearch-http/src/routes/mod.rs
index e5a416cd5..608bc8a67 100644
--- a/meilisearch-http/src/routes/mod.rs
+++ b/meilisearch-http/src/routes/mod.rs
@@ -115,7 +115,7 @@ pub fn load_routes(app: &mut tide::Server<Data>) {
         .delete(|ctx| into_response(stop_words::delete(ctx)));
 
     app.at("/indexes/:index/stats")
-        .get(|ctx| into_response(stats::index_stat(ctx)));
+        .get(|ctx| into_response(stats::index_stats(ctx)));
 
     app.at("/keys/")
         .get(|ctx| into_response(key::list(ctx)))
diff --git a/meilisearch-http/src/routes/search.rs b/meilisearch-http/src/routes/search.rs
index ba25b8aba..2ed423334 100644
--- a/meilisearch-http/src/routes/search.rs
+++ b/meilisearch-http/src/routes/search.rs
@@ -64,7 +64,7 @@ pub async fn search_with_url_query(ctx: Request<Data>) -> SResult<Response> {
             let attributes_to_crop = schema
                 .displayed_name()
                 .iter()
-                .map(|attr| ((*attr).to_string(), crop_length))
+                .map(|attr| (attr.to_string(), crop_length))
                 .collect();
             search_builder.attributes_to_crop(attributes_to_crop);
         } else {
@@ -81,7 +81,7 @@ pub async fn search_with_url_query(ctx: Request<Data>) -> SResult<Response> {
             schema
                 .displayed_name()
                 .iter()
-                .map(|s| (*s).to_string())
+                .map(|s| s.to_string())
                 .collect()
         } else {
             attributes_to_highlight
diff --git a/meilisearch-http/src/routes/stats.rs b/meilisearch-http/src/routes/stats.rs
index c03dfefc0..a158d16da 100644
--- a/meilisearch-http/src/routes/stats.rs
+++ b/meilisearch-http/src/routes/stats.rs
@@ -21,7 +21,7 @@ struct IndexStatsResponse {
     fields_frequency: HashMap<String, usize>,
 }
 
-pub async fn index_stat(ctx: Request<Data>) -> SResult<Response> {
+pub async fn index_stats(ctx: Request<Data>) -> SResult<Response> {
     ctx.is_allowed(Admin)?;
     let index_uid = ctx.url_param("index")?;
     let index = ctx.index()?;
diff --git a/meilisearch-http/tests/.DS_Store b/meilisearch-http/tests/.DS_Store
deleted file mode 100644
index ceb1037ec..000000000
Binary files a/meilisearch-http/tests/.DS_Store and /dev/null differ
diff --git a/meilisearch-http/tests/assets/.DS_Store b/meilisearch-http/tests/assets/.DS_Store
deleted file mode 100644
index bbb23fefa..000000000
Binary files a/meilisearch-http/tests/assets/.DS_Store and /dev/null differ
diff --git a/meilisearch-schema/src/schema.rs b/meilisearch-schema/src/schema.rs
index 0181e2e2a..5a3858f0d 100644
--- a/meilisearch-schema/src/schema.rs
+++ b/meilisearch-schema/src/schema.rs
@@ -1,8 +1,6 @@
-use std::collections::{HashMap, HashSet};
-
-use serde::{Serialize, Deserialize};
-
 use crate::{FieldsMap, FieldId, SResult, Error, IndexedPos};
+use serde::{Serialize, Deserialize};
+use std::collections::{HashMap, HashSet};
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct Schema {
@@ -60,11 +58,11 @@ impl Schema {
         self.fields_map.id(name).is_some()
     }
 
-    pub fn get_or_create_empty(&mut self, name: &str) -> SResult<FieldId> {
+    pub fn insert(&mut self, name: &str) -> SResult<FieldId> {
         self.fields_map.insert(name)
     }
 
-    pub fn get_or_create(&mut self, name: &str) -> SResult<FieldId> {
+    pub fn insert_and_index(&mut self, name: &str) -> SResult<FieldId> {
         match self.fields_map.id(name) {
             Some(id) => {
                 Ok(id)
@@ -80,24 +78,24 @@ impl Schema {
         }
     }
 
-    pub fn ranked(&self) -> HashSet<FieldId> {
-        self.ranked.clone()
+    pub fn ranked(&self) -> &HashSet<FieldId> {
+        &self.ranked
     }
 
     pub fn ranked_name(&self) -> HashSet<&str> {
         self.ranked.iter().filter_map(|a| self.name(*a)).collect()
     }
 
-    pub fn displayed(&self) -> HashSet<FieldId> {
-        self.displayed.clone()
+    pub fn displayed(&self) -> &HashSet<FieldId> {
+        &self.displayed
     }
 
     pub fn displayed_name(&self) -> HashSet<&str> {
         self.displayed.iter().filter_map(|a| self.name(*a)).collect()
     }
 
-    pub fn indexed(&self) -> Vec<FieldId> {
-        self.indexed.clone()
+    pub fn indexed(&self) -> &Vec<FieldId> {
+        &self.indexed
     }
 
     pub fn indexed_name(&self) -> Vec<&str> {
@@ -168,7 +166,7 @@ impl Schema {
     }
 
     pub fn update_ranked<S: AsRef<str>>(&mut self, data: impl IntoIterator<Item = S>) -> SResult<()> {
-        self.ranked = HashSet::new();
+        self.ranked.clear();
         for name in data {
             self.set_ranked(name.as_ref())?;
         }
@@ -176,7 +174,7 @@ impl Schema {
     }
 
     pub fn update_displayed<S: AsRef<str>>(&mut self, data: impl IntoIterator<Item = S>) -> SResult<()> {
-        self.displayed = HashSet::new();
+        self.displayed.clear();
         for name in data {
             self.set_displayed(name.as_ref())?;
         }
@@ -184,8 +182,8 @@ impl Schema {
     }
 
     pub fn update_indexed<S: AsRef<str>>(&mut self, data: Vec<S>) -> SResult<()> {
-        self.indexed = Vec::new();
-        self.indexed_map = HashMap::new();
+        self.indexed.clear();
+        self.indexed_map.clear();
         for name in data {
             self.set_indexed(name.as_ref())?;
         }
diff --git a/meilisearch-types/src/lib.rs b/meilisearch-types/src/lib.rs
index 54202edbc..fac361415 100644
--- a/meilisearch-types/src/lib.rs
+++ b/meilisearch-types/src/lib.rs
@@ -28,7 +28,7 @@ pub struct DocIndex {
 
     /// The attribute in the document where the word was found
     /// along with the index in it.
-    /// Is an IndexedPos and not FieldId. Must be convert each time.
+    /// This is an IndexedPos and not a FieldId. Must be converted each time.
     pub attribute: u16,
     pub word_index: u16,