Extract the vectors from the documents

milli/src/update/index_documents/mod.rs

@@ -304,6 +304,8 @@ where
             }
             None => None,
         };
+        // get the fid of the `_vector` field.
+        let vector_field_id = self.index.fields_ids_map(self.wtxn)?.id("_vector");
 
         let stop_words = self.index.stop_words(self.wtxn)?;
         let exact_attributes = self.index.exact_attributes_ids(self.wtxn)?;
@@ -340,6 +342,7 @@ where
                     faceted_fields,
                     primary_key_id,
                     geo_fields_ids,
+                    vector_field_id,
                     stop_words,
                     max_positions_per_attributes,
                     exact_attributes,