diff --git a/swh/dataset/exporters/orc.py b/swh/dataset/exporters/orc.py
--- a/swh/dataset/exporters/orc.py
+++ b/swh/dataset/exporters/orc.py
@@ -119,14 +119,13 @@
         config = self.config.get("orc", {})
         self.max_rows = config.get("max_rows", {})
         invalid_tables = [
-            table_name for table_name in self.max_rows
-            if table_name not in MAIN_TABLES
+            table_name for table_name in self.max_rows if table_name not in MAIN_TABLES
         ]
         if invalid_tables:
             raise ValueError(
                 "Limiting the number of secondary table (%s) is not supported "
                 "for now.",
-                invalid_tables
+                invalid_tables,
             )
         self._reset()
 
@@ -176,12 +175,10 @@
                     self.uuids.pop(table)
                     self.uuid_main_table.pop(uuid, None)
 
-    def get_writer_for(self, table_name: str, directory_name=None, unique_id=None):
+    def get_writer_for(self, table_name: str, unique_id=None):
         self.maybe_close_writer_for(table_name)
         if table_name not in self.writers:
-            if directory_name is None:
-                directory_name = table_name
-            object_type_dir = self.export_path / directory_name
+            object_type_dir = self.export_path / table_name
             object_type_dir.mkdir(exist_ok=True)
             if unique_id is None:
                 unique_id = self.get_unique_file_id()
@@ -246,9 +243,7 @@
         # we want to store branches in the same directory as snapshot objects,
         # and have both files have the same UUID.
         snapshot_branch_writer = self.get_writer_for(
-            "snapshot_branch",
-            directory_name="snapshot",
-            unique_id=self.uuids["snapshot"],
+            "snapshot_branch", unique_id=self.uuids["snapshot"],
         )
         for branch_name, branch in snapshot["branches"].items():
             if branch is None:
@@ -294,9 +289,7 @@
         )
 
         revision_history_writer = self.get_writer_for(
-            "revision_history",
-            directory_name="revision",
-            unique_id=self.uuids["revision"],
+            "revision_history", unique_id=self.uuids["revision"],
         )
         for i, parent_id in enumerate(revision["parents"]):
             revision_history_writer.write(
@@ -308,9 +301,7 @@
             )
 
         revision_header_writer = self.get_writer_for(
-            "revision_extra_headers",
-            directory_name="revision",
-            unique_id=self.uuids["revision"],
+            "revision_extra_headers", unique_id=self.uuids["revision"],
         )
         for key, value in revision["extra_headers"]:
             revision_header_writer.write(
@@ -324,9 +315,7 @@
         )
 
         directory_entry_writer = self.get_writer_for(
-            "directory_entry",
-            directory_name="directory",
-            unique_id=self.uuids["directory"],
+            "directory_entry", unique_id=self.uuids["directory"],
         )
         for entry in directory["entries"]:
             directory_entry_writer.write(
diff --git a/swh/dataset/test/test_orc.py b/swh/dataset/test/test_orc.py
--- a/swh/dataset/test/test_orc.py
+++ b/swh/dataset/test/test_orc.py
@@ -237,9 +237,9 @@
 )
 @pytest.mark.parametrize("max_rows", (None, 1, 2, 10000))
 def test_export_related_files(max_rows, obj_type, tmpdir):
-    config = {}
+    config = {"orc": {}}
     if max_rows is not None:
-        config["orc"] = {"max_rows": {obj_type: max_rows}}
+        config["orc"]["max_rows"] = {obj_type: max_rows}
     exporter({obj_type: TEST_OBJECTS[obj_type]}, config=config, tmpdir=tmpdir)
     # check there are as many ORC files as objects
     orcfiles = [fname for fname in (tmpdir / obj_type).listdir(f"{obj_type}-*.orc")]
@@ -250,7 +250,7 @@
     # check the number of related ORC files
     for related in RELATED.get(obj_type, ()):
         related_orcfiles = [
-            fname for fname in (tmpdir / obj_type).listdir(f"{related}-*.orc")
+            fname for fname in (tmpdir / related).listdir(f"{related}-*.orc")
         ]
         assert len(related_orcfiles) == len(orcfiles)
 
@@ -268,7 +268,7 @@
 
         # check the related tables
         for related in RELATED.get(obj_type, ()):
-            orc_file = tmpdir / obj_type / f"{related}-{uuid}.orc"
+            orc_file = tmpdir / related / f"{related}-{uuid}.orc"
             with orc_file.open("rb") as orc_obj:
                 reader = pyorc.Reader(
                     orc_obj,
@@ -281,6 +281,22 @@
                     assert row[0] in obj_ids
 
 
+@pytest.mark.parametrize(
+    "obj_type", MAIN_TABLES.keys(),
+)
+def test_export_related_files_separated(obj_type, tmpdir):
+    exporter({obj_type: TEST_OBJECTS[obj_type]}, tmpdir=tmpdir)
+    # check there are as many ORC files as objects
+    orcfiles = [fname for fname in (tmpdir / obj_type).listdir(f"{obj_type}-*.orc")]
+    assert len(orcfiles) == 1
+    # check related ORC files are in their own directory
+    for related in RELATED.get(obj_type, ()):
+        related_orcfiles = [
+            fname for fname in (tmpdir / related).listdir(f"{related}-*.orc")
+        ]
+        assert len(related_orcfiles) == len(orcfiles)
+
+
 @pytest.mark.parametrize("table_name", RELATION_TABLES.keys())
 def test_export_invalid_max_rows(table_name):
     config = {"orc": {"max_rows": {table_name: 10}}}