Feature: Replace Whoosh with tantivy search backend (#12471)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Antoine Mérino <3023499+Merinorus@users.noreply.github.com>

src/documents/tests/test_api_search.py

@@ -2,6 +2,7 @@ import datetime
 from datetime import timedelta
 from unittest import mock
 
+import pytest
 from dateutil.relativedelta import relativedelta
 from django.contrib.auth.models import Group
 from django.contrib.auth.models import Permission
@@ -11,9 +12,7 @@ from django.utils import timezone
 from guardian.shortcuts import assign_perm
 from rest_framework import status
 from rest_framework.test import APITestCase
-from whoosh.writing import AsyncWriter
 
-from documents import index
 from documents.bulk_edit import set_permissions
 from documents.models import Correspondent
 from documents.models import CustomField
@@ -25,18 +24,27 @@ from documents.models import SavedView
 from documents.models import StoragePath
 from documents.models import Tag
 from documents.models import Workflow
+from documents.search import get_backend
+from documents.search import reset_backend
 from documents.tests.utils import DirectoriesMixin
 from paperless_mail.models import MailAccount
 from paperless_mail.models import MailRule
 
+pytestmark = pytest.mark.search
+
 
 class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
     def setUp(self) -> None:
         super().setUp()
+        reset_backend()
 
         self.user = User.objects.create_superuser(username="temp_admin")
         self.client.force_authenticate(user=self.user)
 
+    def tearDown(self) -> None:
+        reset_backend()
+        super().tearDown()
+
     def test_search(self) -> None:
         d1 = Document.objects.create(
             title="invoice",
@@ -57,13 +65,11 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             checksum="C",
             original_filename="someepdf.pdf",
         )
-        with AsyncWriter(index.open_index()) as writer:
-            # Note to future self: there is a reason we dont use a model signal handler to update the index: some operations edit many documents at once
-            # (retagger, renamer) and we don't want to open a writer for each of these, but rather perform the entire operation with one writer.
-            # That's why we can't open the writer in a model on_save handler or something.
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
+
         response = self.client.get("/api/documents/?query=bank")
         results = response.data["results"]
         self.assertEqual(response.data["count"], 3)
@@ -98,9 +104,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             checksum="B",
             pk=2,
         )
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
 
         response = self.client.get(
             "/api/documents/?query=bank",
@@ -127,8 +133,7 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         )
         matching_doc.tags.add(tag)
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, matching_doc)
+        get_backend().add_or_update(matching_doc)
 
         response = self.client.get(
             "/api/documents/?query=bank&include_selection_data=true",
@@ -187,10 +192,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             value_int=20,
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get(
             f"/api/documents/?query=match&ordering=custom_field_{custom_field.pk}",
@@ -211,15 +216,15 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         )
 
     def test_search_multi_page(self) -> None:
-        with AsyncWriter(index.open_index()) as writer:
-            for i in range(55):
-                doc = Document.objects.create(
-                    checksum=str(i),
-                    pk=i + 1,
-                    title=f"Document {i + 1}",
-                    content="content",
-                )
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for i in range(55):
+            doc = Document.objects.create(
+                checksum=str(i),
+                pk=i + 1,
+                title=f"Document {i + 1}",
+                content="content",
+            )
+            backend.add_or_update(doc)
 
         # This is here so that we test that no document gets returned twice (might happen if the paging is not working)
         seen_ids = []
@@ -246,15 +251,15 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             seen_ids.append(result["id"])
 
     def test_search_invalid_page(self) -> None:
-        with AsyncWriter(index.open_index()) as writer:
-            for i in range(15):
-                doc = Document.objects.create(
-                    checksum=str(i),
-                    pk=i + 1,
-                    title=f"Document {i + 1}",
-                    content="content",
-                )
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for i in range(15):
+            doc = Document.objects.create(
+                checksum=str(i),
+                pk=i + 1,
+                title=f"Document {i + 1}",
+                content="content",
+            )
+            backend.add_or_update(doc)
 
         response = self.client.get("/api/documents/?query=content&page=0&page_size=10")
         self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
@@ -292,26 +297,25 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             pk=3,
             checksum="C",
         )
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:[-1 week to now]")
         results = response.data["results"]
         # Expect 3 documents returned
         self.assertEqual(len(results), 3)
 
-        for idx, subset in enumerate(
-            [
-                {"id": 1, "title": "invoice"},
-                {"id": 2, "title": "bank statement 1"},
-                {"id": 3, "title": "bank statement 3"},
-            ],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        result_map = {r["id"]: r for r in results}
+        self.assertEqual(set(result_map.keys()), {1, 2, 3})
+        for subset in [
+            {"id": 1, "title": "invoice"},
+            {"id": 2, "title": "bank statement 1"},
+            {"id": 3, "title": "bank statement 3"},
+        ]:
+            r = result_map[subset["id"]]
+            self.assertDictEqual(r, {**r, **subset})
 
     @override_settings(
         TIME_ZONE="America/Chicago",
@@ -347,10 +351,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             # 7 days, 1 hour and 1 minute ago
             added=timezone.now() - timedelta(days=7, hours=1, minutes=1),
         )
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:[-1 week to now]")
         results = response.data["results"]
@@ -358,12 +362,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Expect 2 documents returned
         self.assertEqual(len(results), 2)
 
-        for idx, subset in enumerate(
-            [{"id": 1, "title": "invoice"}, {"id": 2, "title": "bank statement 1"}],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        result_map = {r["id"]: r for r in results}
+        self.assertEqual(set(result_map.keys()), {1, 2})
+        for subset in [
+            {"id": 1, "title": "invoice"},
+            {"id": 2, "title": "bank statement 1"},
+        ]:
+            r = result_map[subset["id"]]
+            self.assertDictEqual(r, {**r, **subset})
 
     @override_settings(
         TIME_ZONE="Europe/Sofia",
@@ -399,10 +405,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             # 7 days, 1 hour and 1 minute ago
             added=timezone.now() - timedelta(days=7, hours=1, minutes=1),
         )
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:[-1 week to now]")
         results = response.data["results"]
@@ -410,12 +416,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Expect 2 documents returned
         self.assertEqual(len(results), 2)
 
-        for idx, subset in enumerate(
-            [{"id": 1, "title": "invoice"}, {"id": 2, "title": "bank statement 1"}],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        result_map = {r["id"]: r for r in results}
+        self.assertEqual(set(result_map.keys()), {1, 2})
+        for subset in [
+            {"id": 1, "title": "invoice"},
+            {"id": 2, "title": "bank statement 1"},
+        ]:
+            r = result_map[subset["id"]]
+            self.assertDictEqual(r, {**r, **subset})
 
     def test_search_added_in_last_month(self) -> None:
         """
@@ -451,10 +459,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             added=timezone.now() - timedelta(days=7, hours=1, minutes=1),
         )
 
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:[-1 month to now]")
         results = response.data["results"]
@@ -462,12 +470,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Expect 2 documents returned
         self.assertEqual(len(results), 2)
 
-        for idx, subset in enumerate(
-            [{"id": 1, "title": "invoice"}, {"id": 3, "title": "bank statement 3"}],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        result_map = {r["id"]: r for r in results}
+        self.assertEqual(set(result_map.keys()), {1, 3})
+        for subset in [
+            {"id": 1, "title": "invoice"},
+            {"id": 3, "title": "bank statement 3"},
+        ]:
+            r = result_map[subset["id"]]
+            self.assertDictEqual(r, {**r, **subset})
 
     @override_settings(
         TIME_ZONE="America/Denver",
@@ -507,10 +517,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             added=timezone.now() - timedelta(days=7, hours=1, minutes=1),
         )
 
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:[-1 month to now]")
         results = response.data["results"]
@@ -518,12 +528,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Expect 2 documents returned
         self.assertEqual(len(results), 2)
 
-        for idx, subset in enumerate(
-            [{"id": 1, "title": "invoice"}, {"id": 3, "title": "bank statement 3"}],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        result_map = {r["id"]: r for r in results}
+        self.assertEqual(set(result_map.keys()), {1, 3})
+        for subset in [
+            {"id": 1, "title": "invoice"},
+            {"id": 3, "title": "bank statement 3"},
+        ]:
+            r = result_map[subset["id"]]
+            self.assertDictEqual(r, {**r, **subset})
 
     @override_settings(
         TIME_ZONE="Europe/Sofia",
@@ -563,10 +575,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Django converts dates to UTC
         d3.refresh_from_db()
 
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/documents/?query=added:20231201")
         results = response.data["results"]
@@ -574,12 +586,8 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         # Expect 1 document returned
         self.assertEqual(len(results), 1)
 
-        for idx, subset in enumerate(
-            [{"id": 3, "title": "bank statement 3"}],
-        ):
-            result = results[idx]
-            # Assert subset in results
-            self.assertDictEqual(result, {**result, **subset})
+        self.assertEqual(results[0]["id"], 3)
+        self.assertEqual(results[0]["title"], "bank statement 3")
 
     def test_search_added_invalid_date(self) -> None:
         """
@@ -588,7 +596,7 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         WHEN:
             - Query with invalid added date
         THEN:
-            - No documents returned
+            - 400 Bad Request returned (Tantivy rejects invalid date field syntax)
         """
         d1 = Document.objects.create(
             title="invoice",
@@ -597,16 +605,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             pk=1,
         )
 
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
+        get_backend().add_or_update(d1)
 
         response = self.client.get("/api/documents/?query=added:invalid-date")
-        results = response.data["results"]
 
-        # Expect 0 document returned
-        self.assertEqual(len(results), 0)
+        # Tantivy rejects unparsable field queries with a 400
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
 
-    @mock.patch("documents.index.autocomplete")
+    @mock.patch("documents.search._backend.TantivyBackend.autocomplete")
     def test_search_autocomplete_limits(self, m) -> None:
         """
         GIVEN:
@@ -618,7 +624,7 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             - Limit requests are obeyed
         """
 
-        m.side_effect = lambda ix, term, limit, user: [term for _ in range(limit)]
+        m.side_effect = lambda term, limit, user=None: [term for _ in range(limit)]
 
         response = self.client.get("/api/search/autocomplete/?term=test")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
@@ -671,32 +677,29 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             owner=u1,
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/search/autocomplete/?term=app")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(response.data, [b"apples", b"applebaum", b"appletini"])
+        self.assertEqual(response.data, ["applebaum", "apples", "appletini"])
 
         d3.owner = u2
-
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d3)
+        d3.save()
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/search/autocomplete/?term=app")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(response.data, [b"apples", b"applebaum"])
+        self.assertEqual(response.data, ["applebaum", "apples"])
 
         assign_perm("view_document", u1, d3)
-
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d3)
+        backend.add_or_update(d3)
 
         response = self.client.get("/api/search/autocomplete/?term=app")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(response.data, [b"apples", b"applebaum", b"appletini"])
+        self.assertEqual(response.data, ["applebaum", "apples", "appletini"])
 
     def test_search_autocomplete_field_name_match(self) -> None:
         """
@@ -714,8 +717,7 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             checksum="1",
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
+        get_backend().add_or_update(d1)
 
         response = self.client.get("/api/search/autocomplete/?term=created:2023")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
@@ -736,33 +738,36 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             checksum="1",
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
+        get_backend().add_or_update(d1)
 
         response = self.client.get("/api/search/autocomplete/?term=auto")
         self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(response.data[0], b"auto")
+        self.assertEqual(response.data[0], "auto")
 
-    def test_search_spelling_suggestion(self) -> None:
-        with AsyncWriter(index.open_index()) as writer:
-            for i in range(55):
-                doc = Document.objects.create(
-                    checksum=str(i),
-                    pk=i + 1,
-                    title=f"Document {i + 1}",
-                    content=f"Things document {i + 1}",
-                )
-                index.update_document(writer, doc)
+    def test_search_no_spelling_suggestion(self) -> None:
+        """
+        GIVEN:
+            - Documents exist with various terms
+        WHEN:
+            - Query for documents with any term
+        THEN:
+            - corrected_query is always None (Tantivy has no spell correction)
+        """
+        backend = get_backend()
+        for i in range(5):
+            doc = Document.objects.create(
+                checksum=str(i),
+                pk=i + 1,
+                title=f"Document {i + 1}",
+                content=f"Things document {i + 1}",
+            )
+            backend.add_or_update(doc)
 
         response = self.client.get("/api/documents/?query=thing")
-        correction = response.data["corrected_query"]
-
-        self.assertEqual(correction, "things")
+        self.assertIsNone(response.data["corrected_query"])
 
         response = self.client.get("/api/documents/?query=things")
-        correction = response.data["corrected_query"]
-
-        self.assertEqual(correction, None)
+        self.assertIsNone(response.data["corrected_query"])
 
     def test_search_spelling_suggestion_suppressed_for_private_terms(self):
         owner = User.objects.create_user("owner")
@@ -771,24 +776,24 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             Permission.objects.get(codename="view_document"),
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            for i in range(55):
-                private_doc = Document.objects.create(
-                    checksum=f"p{i}",
-                    pk=100 + i,
-                    title=f"Private Document {i + 1}",
-                    content=f"treasury document {i + 1}",
-                    owner=owner,
-                )
-                visible_doc = Document.objects.create(
-                    checksum=f"v{i}",
-                    pk=200 + i,
-                    title=f"Visible Document {i + 1}",
-                    content=f"public ledger {i + 1}",
-                    owner=attacker,
-                )
-                index.update_document(writer, private_doc)
-                index.update_document(writer, visible_doc)
+        backend = get_backend()
+        for i in range(5):
+            private_doc = Document.objects.create(
+                checksum=f"p{i}",
+                pk=100 + i,
+                title=f"Private Document {i + 1}",
+                content=f"treasury document {i + 1}",
+                owner=owner,
+            )
+            visible_doc = Document.objects.create(
+                checksum=f"v{i}",
+                pk=200 + i,
+                title=f"Visible Document {i + 1}",
+                content=f"public ledger {i + 1}",
+                owner=attacker,
+            )
+            backend.add_or_update(private_doc)
+            backend.add_or_update(visible_doc)
 
         self.client.force_authenticate(user=attacker)
 
@@ -798,26 +803,6 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         self.assertEqual(response.data["count"], 0)
         self.assertIsNone(response.data["corrected_query"])
 
-    @mock.patch(
-        "whoosh.searching.Searcher.correct_query",
-        side_effect=Exception("Test error"),
-    )
-    def test_corrected_query_error(self, mock_correct_query) -> None:
-        """
-        GIVEN:
-            - A query that raises an error on correction
-        WHEN:
-            - API request for search with that query
-        THEN:
-            - The error is logged and the search proceeds
-        """
-        with self.assertLogs("paperless.index", level="INFO") as cm:
-            response = self.client.get("/api/documents/?query=2025-06-04")
-            self.assertEqual(response.status_code, status.HTTP_200_OK)
-            error_str = cm.output[0]
-            expected_str = "Error while correcting query '2025-06-04': Test error"
-            self.assertIn(expected_str, error_str)
-
     def test_search_more_like(self) -> None:
         """
         GIVEN:
@@ -847,16 +832,16 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             checksum="C",
         )
         d4 = Document.objects.create(
-            title="Monty Python & the Holy Grail",
-            content="And now for something completely different",
+            title="Quarterly Report",
+            content="quarterly revenue profit margin earnings growth",
             pk=4,
             checksum="ABC",
         )
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
-            index.update_document(writer, d4)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
+        backend.add_or_update(d4)
 
         response = self.client.get(f"/api/documents/?more_like_id={d2.id}")
 
@@ -864,9 +849,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
 
         results = response.data["results"]
 
-        self.assertEqual(len(results), 2)
-        self.assertEqual(results[0]["id"], d3.id)
-        self.assertEqual(results[1]["id"], d1.id)
+        self.assertGreaterEqual(len(results), 1)
+        result_ids = [r["id"] for r in results]
+        self.assertIn(d3.id, result_ids)
+        self.assertNotIn(d4.id, result_ids)
 
     def test_search_more_like_requires_view_permission_on_seed_document(
         self,
@@ -908,10 +894,10 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             pk=12,
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            index.update_document(writer, private_seed)
-            index.update_document(writer, visible_doc)
-            index.update_document(writer, other_doc)
+        backend = get_backend()
+        backend.add_or_update(private_seed)
+        backend.add_or_update(visible_doc)
+        backend.add_or_update(other_doc)
 
         self.client.force_authenticate(user=attacker)
 
@@ -985,9 +971,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             value_text="foobard4",
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            for doc in Document.objects.all():
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for doc in Document.objects.all():
+            backend.add_or_update(doc)
 
         def search_query(q):
             r = self.client.get("/api/documents/?query=test" + q)
@@ -1203,9 +1189,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         Document.objects.create(checksum="3", content="test 3", owner=u2)
         Document.objects.create(checksum="4", content="test 4")
 
-        with AsyncWriter(index.open_index()) as writer:
-            for doc in Document.objects.all():
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for doc in Document.objects.all():
+            backend.add_or_update(doc)
 
         self.client.force_authenticate(user=u1)
         r = self.client.get("/api/documents/?query=test")
@@ -1256,9 +1242,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         d3 = Document.objects.create(checksum="3", content="test 3", owner=u2)
         Document.objects.create(checksum="4", content="test 4")
 
-        with AsyncWriter(index.open_index()) as writer:
-            for doc in Document.objects.all():
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for doc in Document.objects.all():
+            backend.add_or_update(doc)
 
         self.client.force_authenticate(user=u1)
         r = self.client.get("/api/documents/?query=test")
@@ -1278,9 +1264,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         assign_perm("view_document", u1, d3)
         assign_perm("view_document", u2, d1)
 
-        with AsyncWriter(index.open_index()) as writer:
-            for doc in [d1, d2, d3]:
-                index.update_document(writer, doc)
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
 
         self.client.force_authenticate(user=u1)
         r = self.client.get("/api/documents/?query=test")
@@ -1343,9 +1329,9 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             user=u1,
         )
 
-        with AsyncWriter(index.open_index()) as writer:
-            for doc in Document.objects.all():
-                index.update_document(writer, doc)
+        backend = get_backend()
+        for doc in Document.objects.all():
+            backend.add_or_update(doc)
 
         def search_query(q):
             r = self.client.get("/api/documents/?query=test" + q)
@@ -1378,13 +1364,14 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
             search_query("&ordering=-num_notes"),
             [d1.id, d3.id, d2.id],
         )
+        # owner sort: ORM orders by owner_id (integer); NULLs first in SQLite ASC
         self.assertListEqual(
             search_query("&ordering=owner"),
-            [d1.id, d2.id, d3.id],
+            [d3.id, d1.id, d2.id],
         )
         self.assertListEqual(
             search_query("&ordering=-owner"),
-            [d3.id, d2.id, d1.id],
+            [d2.id, d1.id, d3.id],
         )
 
     @mock.patch("documents.bulk_edit.bulk_update_documents")
@@ -1441,12 +1428,12 @@ class TestDocumentSearchApi(DirectoriesMixin, APITestCase):
         )
         set_permissions([4, 5], set_permissions={}, owner=user2, merge=False)
 
-        with index.open_index_writer() as writer:
-            index.update_document(writer, d1)
-            index.update_document(writer, d2)
-            index.update_document(writer, d3)
-            index.update_document(writer, d4)
-            index.update_document(writer, d5)
+        backend = get_backend()
+        backend.add_or_update(d1)
+        backend.add_or_update(d2)
+        backend.add_or_update(d3)
+        backend.add_or_update(d4)
+        backend.add_or_update(d5)
 
         correspondent1 = Correspondent.objects.create(name="bank correspondent 1")
         Correspondent.objects.create(name="correspondent 2")