From 8035ca71387989e10784a25dc42046130d4c5a63 Mon Sep 17 00:00:00 2001
From: mpostma <postma.marin@protonmail.com>
Date: Tue, 16 Jun 2020 10:45:17 +0200
Subject: [PATCH] fix distinct attribute behavior

---
 meilisearch-core/src/store/main.rs            | 10 ++++-----
 .../src/update/settings_update.rs             |  3 ++-
 meilisearch-http/src/helpers/meilisearch.rs   | 22 +++++++++----------
 meilisearch-http/src/routes/setting.rs        |  6 ++++-
 4 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/meilisearch-core/src/store/main.rs b/meilisearch-core/src/store/main.rs
index f1ef6fc5e..9d5e95425 100644
--- a/meilisearch-core/src/store/main.rs
+++ b/meilisearch-core/src/store/main.rs
@@ -286,15 +286,15 @@ impl Main {
         Ok(self.main.delete::<_, Str>(writer, RANKING_RULES_KEY)?)
     }
 
-    pub fn distinct_attribute(&self, reader: &heed::RoTxn<MainT>) -> MResult<Option<String>> {
-        if let Some(value) = self.main.get::<_, Str, Str>(reader, DISTINCT_ATTRIBUTE_KEY)? {
-            return Ok(Some(value.to_owned()))
+    pub fn distinct_attribute(&self, reader: &heed::RoTxn<MainT>) -> MResult<Option<FieldId>> {
+        if let Some(value) = self.main.get::<_, Str, OwnedType<u16>>(reader, DISTINCT_ATTRIBUTE_KEY)? {
+            return Ok(Some(FieldId(value.to_owned())))
         }
         return Ok(None)
     }
 
-    pub fn put_distinct_attribute(self, writer: &mut heed::RwTxn<MainT>, value: &str) -> MResult<()> {
-        Ok(self.main.put::<_, Str, Str>(writer, DISTINCT_ATTRIBUTE_KEY, value)?)
+    pub fn put_distinct_attribute(self, writer: &mut heed::RwTxn<MainT>, value: FieldId) -> MResult<()> {
+        Ok(self.main.put::<_, Str, OwnedType<u16>>(writer, DISTINCT_ATTRIBUTE_KEY, &value.0)?)
     }
 
     pub fn delete_distinct_attribute(self, writer: &mut heed::RwTxn<MainT>) -> MResult<bool> {
diff --git a/meilisearch-core/src/update/settings_update.rs b/meilisearch-core/src/update/settings_update.rs
index fbf266001..9aecb23f7 100644
--- a/meilisearch-core/src/update/settings_update.rs
+++ b/meilisearch-core/src/update/settings_update.rs
@@ -59,7 +59,8 @@ pub fn apply_settings_update(
 
     match settings.distinct_attribute {
         UpdateState::Update(v) => {
-            index.main.put_distinct_attribute(writer, &v)?;
+            let field_id = schema.insert(&v)?;
+            index.main.put_distinct_attribute(writer, field_id)?;
         },
         UpdateState::Clear => {
             index.main.delete_distinct_attribute(writer)?;
diff --git a/meilisearch-http/src/helpers/meilisearch.rs b/meilisearch-http/src/helpers/meilisearch.rs
index 65b6da08f..f9183d013 100644
--- a/meilisearch-http/src/helpers/meilisearch.rs
+++ b/meilisearch-http/src/helpers/meilisearch.rs
@@ -139,19 +139,17 @@ impl<'a> SearchBuilder<'a> {
         }
 
         if let Some(field) = self.index.main.distinct_attribute(reader)? {
-            if let Some(field_id) = schema.id(&field) {
-                let index = &self.index;
-                query_builder.with_distinct(1, move |id| {
-                    match index.document_attribute_bytes(reader, id, field_id) {
-                        Ok(Some(bytes)) => {
-                            let mut s = SipHasher::new();
-                            bytes.hash(&mut s);
-                            Some(s.finish())
-                        }
-                        _ => None,
+            let index = &self.index;
+            query_builder.with_distinct(1, move |id| {
+                match index.document_attribute_bytes(reader, id, field) {
+                    Ok(Some(bytes)) => {
+                        let mut s = SipHasher::new();
+                        bytes.hash(&mut s);
+                        Some(s.finish())
                     }
-                });
-            }
+                    _ => None,
+                }
+            });
         }
 
         query_builder.set_facet_filter(self.facet_filters);
diff --git a/meilisearch-http/src/routes/setting.rs b/meilisearch-http/src/routes/setting.rs
index 37fe5bda2..ea35470ae 100644
--- a/meilisearch-http/src/routes/setting.rs
+++ b/meilisearch-http/src/routes/setting.rs
@@ -89,10 +89,14 @@ async fn get_all(
         .map(|r| r.to_string())
         .collect();
 
-    let distinct_attribute = index.main.distinct_attribute(&reader)?;
 
     let schema = index.main.schema(&reader)?;
 
+    let distinct_attribute = match (index.main.distinct_attribute(&reader)?, &schema) {
+        (Some(id), Some(schema)) => schema.name(id).map(str::to_string),
+        _ => None,
+    };
+
     let attributes_for_faceting = match (&schema, &index.main.attributes_for_faceting(&reader)?) {
         (Some(schema), Some(attrs)) => {
             attrs