diff --git a/milli/src/documents/builder.rs b/milli/src/documents/builder.rs
index bb9d6aa68..dc027e1b7 100644
--- a/milli/src/documents/builder.rs
+++ b/milli/src/documents/builder.rs
@@ -216,9 +216,9 @@ mod test {
         assert_eq!(builder.documents_count(), 2);
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
         assert_eq!(index.len(), 3);
 
         let document = cursor.next_document().unwrap().unwrap();
@@ -240,9 +240,9 @@ mod test {
         assert_eq!(builder.documents_count(), 2);
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
         assert_eq!(index.len(), 2);
 
         let document = cursor.next_document().unwrap().unwrap();
@@ -264,9 +264,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
 
@@ -292,9 +292,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -319,9 +319,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -346,9 +346,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -373,9 +373,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -400,9 +400,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -427,9 +427,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -454,9 +454,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
@@ -482,8 +482,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
+        let (mut cursor, _) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         assert!(cursor.next_document().is_err());
     }
@@ -498,9 +499,9 @@ mod test {
         builder.append_csv(csv).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut cursor =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
-        let index = cursor.documents_batch_index().clone();
+        let (mut cursor, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
         let doc = cursor.next_document().unwrap().unwrap();
         let val = obkv_to_object(&doc, &index).map(Value::from).unwrap();
diff --git a/milli/src/documents/enriched.rs b/milli/src/documents/enriched.rs
index 4f45a891a..fa21c0f87 100644
--- a/milli/src/documents/enriched.rs
+++ b/milli/src/documents/enriched.rs
@@ -56,14 +56,13 @@ impl<R: io::Read + io::Seek> EnrichedDocumentsBatchReader<R> {
     }
 
     /// This method returns a forward cursor over the enriched documents.
-    pub fn into_cursor(self) -> EnrichedDocumentsBatchCursor<R> {
+    pub fn into_cursor_and_fields_index(
+        self,
+    ) -> (EnrichedDocumentsBatchCursor<R>, DocumentsBatchIndex) {
         let EnrichedDocumentsBatchReader { documents, primary_key, mut external_ids } = self;
+        let (documents, fields_index) = documents.into_cursor_and_fields_index();
         external_ids.reset();
-        EnrichedDocumentsBatchCursor {
-            documents: documents.into_cursor(),
-            primary_key,
-            external_ids,
-        }
+        (EnrichedDocumentsBatchCursor { documents, primary_key, external_ids }, fields_index)
     }
 }
 
@@ -80,23 +79,9 @@ pub struct EnrichedDocumentsBatchCursor<R> {
 }
 
 impl<R> EnrichedDocumentsBatchCursor<R> {
-    pub fn into_reader(self) -> EnrichedDocumentsBatchReader<R> {
-        let EnrichedDocumentsBatchCursor { documents, primary_key, external_ids } = self;
-        EnrichedDocumentsBatchReader {
-            documents: documents.into_reader(),
-            primary_key,
-            external_ids,
-        }
-    }
-
     pub fn primary_key(&self) -> &str {
         &self.primary_key
     }
-
-    pub fn documents_batch_index(&self) -> &DocumentsBatchIndex {
-        self.documents.documents_batch_index()
-    }
-
     /// Resets the cursor to be able to read from the start again.
     pub fn reset(&mut self) {
         self.documents.reset();
diff --git a/milli/src/documents/mod.rs b/milli/src/documents/mod.rs
index c5ff7a120..e766e29cf 100644
--- a/milli/src/documents/mod.rs
+++ b/milli/src/documents/mod.rs
@@ -203,10 +203,11 @@ mod test {
         builder.append_json_object(value.as_object().unwrap()).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut documents =
-            DocumentsBatchReader::from_reader(Cursor::new(vector)).unwrap().into_cursor();
+        let (mut documents, index) = DocumentsBatchReader::from_reader(Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
 
-        assert_eq!(documents.documents_batch_index().iter().count(), 5);
+        assert_eq!(index.iter().count(), 5);
         let reader = documents.next_document().unwrap().unwrap();
         assert_eq!(reader.iter().count(), 5);
         assert!(documents.next_document().unwrap().is_none());
@@ -226,9 +227,10 @@ mod test {
         builder.append_json_object(doc2.as_object().unwrap()).unwrap();
         let vector = builder.into_inner().unwrap();
 
-        let mut documents =
-            DocumentsBatchReader::from_reader(io::Cursor::new(vector)).unwrap().into_cursor();
-        assert_eq!(documents.documents_batch_index().iter().count(), 2);
+        let (mut documents, index) = DocumentsBatchReader::from_reader(io::Cursor::new(vector))
+            .unwrap()
+            .into_cursor_and_fields_index();
+        assert_eq!(index.iter().count(), 2);
         let reader = documents.next_document().unwrap().unwrap();
         assert_eq!(reader.iter().count(), 1);
         assert!(documents.next_document().unwrap().is_some());
@@ -243,7 +245,7 @@ mod test {
             }
         }]);
 
-        let mut cursor = docs_reader.into_cursor();
+        let (mut cursor, _) = docs_reader.into_cursor_and_fields_index();
         let doc = cursor.next_document().unwrap().unwrap();
         let nested: Value = serde_json::from_slice(doc.get(0).unwrap()).unwrap();
         assert_eq!(nested, json!({ "toto": ["hello"] }));
diff --git a/milli/src/documents/reader.rs b/milli/src/documents/reader.rs
index 70b8b0131..a8a4c662d 100644
--- a/milli/src/documents/reader.rs
+++ b/milli/src/documents/reader.rs
@@ -17,6 +17,10 @@ pub struct DocumentsBatchReader<R> {
 }
 
 impl<R: io::Read + io::Seek> DocumentsBatchReader<R> {
+    pub fn new(cursor: DocumentsBatchCursor<R>, fields_index: DocumentsBatchIndex) -> Self {
+        Self { cursor: cursor.cursor, fields_index }
+    }
+
     /// Construct a `DocumentsReader` from a reader.
     ///
     /// It first retrieves the index, then moves to the first document. Use the `into_cursor`
@@ -46,30 +50,20 @@ impl<R: io::Read + io::Seek> DocumentsBatchReader<R> {
     }
 
     /// This method returns a forward cursor over the documents.
-    pub fn into_cursor(self) -> DocumentsBatchCursor<R> {
+    pub fn into_cursor_and_fields_index(self) -> (DocumentsBatchCursor<R>, DocumentsBatchIndex) {
         let DocumentsBatchReader { cursor, fields_index } = self;
-        let mut cursor = DocumentsBatchCursor { cursor, fields_index };
+        let mut cursor = DocumentsBatchCursor { cursor };
         cursor.reset();
-        cursor
+        (cursor, fields_index)
     }
 }
 
 /// A forward cursor over the documents in a `DocumentsBatchReader`.
 pub struct DocumentsBatchCursor<R> {
     cursor: grenad::ReaderCursor<R>,
-    fields_index: DocumentsBatchIndex,
 }
 
 impl<R> DocumentsBatchCursor<R> {
-    pub fn into_reader(self) -> DocumentsBatchReader<R> {
-        let DocumentsBatchCursor { cursor, fields_index, .. } = self;
-        DocumentsBatchReader { cursor, fields_index }
-    }
-
-    pub fn documents_batch_index(&self) -> &DocumentsBatchIndex {
-        &self.fields_index
-    }
-
     /// Resets the cursor to be able to read from the start again.
     pub fn reset(&mut self) {
         self.cursor.reset();
diff --git a/milli/src/update/index_documents/enrich.rs b/milli/src/update/index_documents/enrich.rs
index 51495c598..7c9a016d8 100644
--- a/milli/src/update/index_documents/enrich.rs
+++ b/milli/src/update/index_documents/enrich.rs
@@ -27,8 +27,8 @@ pub fn enrich_documents_batch<R: Read + Seek>(
     autogenerate_docids: bool,
     reader: DocumentsBatchReader<R>,
 ) -> Result<StdResult<EnrichedDocumentsBatchReader<R>, UserError>> {
-    let mut cursor = reader.into_cursor();
-    let mut documents_batch_index = cursor.documents_batch_index().clone();
+    let (mut cursor, mut documents_batch_index) = reader.into_cursor_and_fields_index();
+
     let mut external_ids = tempfile::tempfile().map(grenad::Writer::new)?;
     let mut uuid_buffer = [0; uuid::fmt::Hyphenated::LENGTH];
 
@@ -103,9 +103,10 @@ pub fn enrich_documents_batch<R: Read + Seek>(
     }
 
     let external_ids = writer_into_reader(external_ids)?;
+    let primary_key_name = primary_key.name().to_string();
     let reader = EnrichedDocumentsBatchReader::new(
-        cursor.into_reader(),
-        primary_key.name().to_string(),
+        DocumentsBatchReader::new(cursor, documents_batch_index),
+        primary_key_name,
         external_ids,
     )?;
 
diff --git a/milli/src/update/index_documents/transform.rs b/milli/src/update/index_documents/transform.rs
index d03a803fd..0de90924a 100644
--- a/milli/src/update/index_documents/transform.rs
+++ b/milli/src/update/index_documents/transform.rs
@@ -146,11 +146,11 @@ impl<'a, 'i> Transform<'a, 'i> {
         R: Read + Seek,
         F: Fn(UpdateIndexingStep) + Sync,
     {
-        let mut cursor = reader.into_cursor();
-        let fields_index = cursor.documents_batch_index();
+        let (mut cursor, fields_index) = reader.into_cursor_and_fields_index();
+
         let external_documents_ids = self.index.external_documents_ids(wtxn)?;
 
-        let mapping = create_fields_mapping(&mut self.fields_ids_map, fields_index)?;
+        let mapping = create_fields_mapping(&mut self.fields_ids_map, &fields_index)?;
 
         let primary_key = cursor.primary_key().to_string();
         let primary_key_id =