fix(example-images): use in-place cache sync and bulk pending-check index for large libraries

py/utils/example_images_download_manager.py

@@ -14,11 +14,16 @@ from ..services.service_registry import ServiceRegistry
 from ..utils.example_images_paths import (
     ExampleImagePathResolver,
     ensure_library_root_exists,
+    get_example_images_root,
+    is_hash_folder,
     uses_library_scoped_folders,
 )
 from ..utils.metadata_manager import MetadataManager
 from .example_images_processor import ExampleImagesProcessor
-from .example_images_metadata import MetadataUpdater
+from .example_images_metadata import (
+    MetadataUpdater,
+    update_cache_from_metadata,
+)
 from ..services.downloader import get_downloader
 from ..services.settings_manager import get_settings_manager
 
@@ -87,6 +92,13 @@ class _DownloadProgress(dict):
         return snapshot
 
 
+# When fewer candidates than this remain in check_pending_models, probe each
+# model folder directly (preserving legacy-folder migration semantics). Above
+# it, build a folder index with a single directory scan so libraries with
+# 100k+ models do not pay one syscall per candidate.
+_BULK_LOOKUP_THRESHOLD = 1000
+
+
 def _model_directory_has_files(path: str) -> bool:
     """Return True when the provided directory exists and contains entries."""
 
@@ -103,6 +115,36 @@ def _model_directory_has_files(path: str) -> bool:
     return False
 
 
+def _build_example_folder_index(output_dir: str) -> dict[str, bool]:
+    """Build a ``{hash: has_files}`` index for a library's example-image folders.
+
+    A single directory scan over the library root replaces ``O(candidates)``
+    per-folder ``os.scandir`` calls, which is required for libraries with
+    100k+ models. Each hash folder is classified by whether it contains any
+    entries, matching the semantics of ``_model_directory_has_files``.
+    """
+
+    index: dict[str, bool] = {}
+    if not output_dir or not os.path.isdir(output_dir):
+        return index
+
+    try:
+        with os.scandir(output_dir) as entries:
+            for entry in entries:
+                name = entry.name
+                if not entry.is_dir() or not is_hash_folder(name):
+                    continue
+                try:
+                    with os.scandir(entry.path) as subentries:
+                        index[name.lower()] = any(subentries)
+                except OSError:
+                    index[name.lower()] = False
+    except OSError:
+        pass
+
+    return index
+
+
 class DownloadManager:
     """Manages downloading example images for models."""
 
@@ -410,14 +452,49 @@ class DownloadManager:
             # Calculate pending count: check which models actually need processing.
             # A model is pending if it has a hash, is not already processed or known-failed,
             # and its folder doesn't exist or is empty.
-            pending_hashes = set()
+            candidate_hashes = [
-            for model_hash, model_name in all_models_with_hash:
+                model_hash
-                if model_hash not in processed_models and model_hash not in failed_models:
+                for model_hash, _ in all_models_with_hash
+                if model_hash not in processed_models
+                and model_hash not in failed_models
+            ]
+
+            pending_hashes: set[str] = set()
+            # For small candidate counts the existing per-folder check is fine
+            # and handles legacy folder migration.
+            # For large libraries, scan the library root once and do set lookups.
+            if len(candidate_hashes) <= _BULK_LOOKUP_THRESHOLD or not output_dir:
+                for model_hash in candidate_hashes:
                     model_dir = ExampleImagePathResolver.get_model_folder(
                         model_hash, active_library
                     )
                     if not _model_directory_has_files(model_dir):
                         pending_hashes.add(model_hash)
+            else:
+                folder_index = await asyncio.get_event_loop().run_in_executor(
+                    None, _build_example_folder_index, output_dir
+                )
+                # In multi-library mode, folders that have not been consolidated
+                # into the library root yet (startup migration skipped, failed
+                # move, or created at the legacy path afterwards) still live at
+                # the legacy root/<hash> location. Only scan that root when at
+                # least one candidate is missing from the library-root index, so
+                # the fully-consolidated case does not pay an extra directory
+                # pass on every call.
+                if uses_library_scoped_folders() and any(
+                    not folder_index.get(model_hash, False)
+                    for model_hash in candidate_hashes
+                ):
+                    legacy_root = get_example_images_root()
+                    if legacy_root and legacy_root != output_dir:
+                        legacy_index = await asyncio.get_event_loop().run_in_executor(
+                            None, _build_example_folder_index, legacy_root
+                        )
+                        for hash_key, has_files in legacy_index.items():
+                            folder_index.setdefault(hash_key, has_files)
+                for model_hash in candidate_hashes:
+                    if not folder_index.get(model_hash, False):
+                        pending_hashes.add(model_hash)
 
             pending_count = len(pending_hashes)
 
@@ -1343,8 +1420,8 @@ class DownloadManager:
                 await MetadataManager.save_metadata(file_path, model_copy)
 
                 try:
-                    await scanner.update_single_model_cache(
+                    await update_cache_from_metadata(
-                        file_path, file_path, model_data
+                        scanner, file_path, model_copy
                     )
                 except AttributeError:
                     logger.debug(

py/utils/example_images_metadata.py

@@ -1,3 +1,4 @@
+import inspect
 import logging
 import os
 import re
@@ -28,6 +29,31 @@ if TYPE_CHECKING:  # pragma: no cover - import for type checkers only
     from ..services.settings_manager import SettingsManager
 
 
+async def update_cache_from_metadata(
+    scanner: Any, file_path: str, metadata: Dict[str, Any]
+) -> bool:
+    """Update the scanner cache from a metadata dict using the in-place sync path.
+
+    ``sync_cache_from_metadata`` patches the existing cache entry incrementally
+    (tag/hash/version indexes, targeted single-row SQL update) and only resorts
+    when a sort-key field changed. This avoids the ``O(n)`` full-list resort and
+    full cache rewrite that ``update_single_model_cache`` performs on every call,
+    which is critical for libraries with 100k+ models.
+
+    Falls back to the legacy full update when the scanner does not expose an
+    async ``sync_cache_from_metadata`` method.
+
+    Returns:
+        ``True`` if the cache entry was updated, ``False`` otherwise.
+    """
+
+    sync_method = getattr(scanner, "sync_cache_from_metadata", None)
+    if inspect.iscoroutinefunction(sync_method):
+        return await sync_method(file_path, metadata)
+
+    return await scanner.update_single_model_cache(file_path, file_path, metadata)
+
+
 def _build_metadata_sync_service(settings_manager: "SettingsManager") -> MetadataSyncService:
     """Construct a metadata sync service bound to the provided settings."""
 
@@ -103,7 +129,7 @@ class MetadataUpdater:
                 progress['refreshed_models'].add(model_hash)
             
             async def update_cache_func(old_path, new_path, metadata):
-                return await scanner.update_single_model_cache(old_path, new_path, metadata)
+                return await update_cache_from_metadata(scanner, new_path, metadata)
 
             await MetadataManager.hydrate_model_data(model_data)
             success, error = await _get_metadata_sync_service().fetch_and_update_model(
@@ -234,6 +260,7 @@ class MetadataUpdater:
                 
                 # Save metadata to .metadata.json file
                 file_path = model.get('file_path')
+                model_copy: Optional[Dict[str, Any]] = None
                 try:
                     model_copy = model.copy()
                     model_copy.pop('folder', None)
@@ -242,13 +269,17 @@ class MetadataUpdater:
                 except Exception as e:
                     logger.error(f"Failed to save metadata for {model.get('model_name')}: {str(e)}")
 
-                # Save updated metadata to scanner cache
+                # Save updated metadata to scanner cache. sync_cache_from_metadata
-                success = await scanner.update_single_model_cache(file_path, file_path, model)
+                # returns False both for "already in sync" and for actual failures,
-                if success:
+                # so the cache sync result is deliberately not treated as an error;
+                # the return value reflects whether the metadata was persisted.
+                if file_path and model_copy is not None:
+                    await update_cache_from_metadata(scanner, file_path, model_copy)
                     logger.info(f"Successfully updated metadata for {model.get('model_name')} with {len(images)} local examples")
                     return True
-                else:
+
                 logger.warning(f"Failed to update metadata for {model.get('model_name')}")
+                return False
             
             return False
         except Exception as e:
@@ -336,6 +367,7 @@ class MetadataUpdater:
             
             # Save metadata to .metadata.json file
             file_path = model_data.get('file_path')
+            model_copy: Optional[Dict[str, Any]] = None
             if file_path:
                 try:
                     model_copy = model_data.copy()
@@ -346,8 +378,8 @@ class MetadataUpdater:
                     logger.error(f"Failed to save metadata: {str(e)}")
 
             # Save updated metadata to scanner cache
-            if file_path:
+            if file_path and model_copy is not None:
-                await scanner.update_single_model_cache(file_path, file_path, model_data)
+                await update_cache_from_metadata(scanner, file_path, model_copy)
 
             # Get regular images array (might be None)
             regular_images = civitai_data.get('images', [])

py/utils/example_images_migration.py

@@ -15,6 +15,7 @@ from ..utils.example_images_paths import (
 )
 from ..utils.metadata_manager import MetadataManager
 from ..utils.example_images_processor import ExampleImagesProcessor
+from ..utils.example_images_metadata import update_cache_from_metadata
 from ..utils.constants import SUPPORTED_MEDIA_EXTENSIONS
 
 logger = logging.getLogger(__name__)
@@ -421,7 +422,7 @@ class ExampleImagesMigration:
                         await MetadataManager.save_metadata(file_path, model_copy)
                         
                         # Update scanner cache
-                        await scanner.update_single_model_cache(file_path, file_path, model_metadata)
+                        await update_cache_from_metadata(scanner, file_path, model_copy)
                         
                         updated_models += 1
                     except Exception as e:

py/utils/example_images_processor.py

@@ -9,7 +9,7 @@ from ..utils.constants import SUPPORTED_MEDIA_EXTENSIONS
 from ..services.service_registry import ServiceRegistry
 from ..services.settings_manager import get_settings_manager
 from ..utils.example_images_paths import get_model_folder, get_model_relative_path
-from .example_images_metadata import MetadataUpdater
+from .example_images_metadata import MetadataUpdater, update_cache_from_metadata
 from ..utils.metadata_manager import MetadataManager
 
 logger = logging.getLogger(__name__)
@@ -644,7 +644,7 @@ class ExampleImagesProcessor:
                     }, status=500)
             
                 # Update cache
-                await scanner.update_single_model_cache(file_path, file_path, model_data)
+                await update_cache_from_metadata(scanner, file_path, model_data)
             
             # Get regular images array (might be None)
             regular_images = civitai_data.get('images', [])
@@ -759,7 +759,7 @@ class ExampleImagesProcessor:
                 model_copy = model_data.copy()
                 model_copy.pop('folder', None)
                 await MetadataManager.save_metadata(file_path, model_copy)
-                await scanner.update_single_model_cache(file_path, file_path, model_data)
+                await update_cache_from_metadata(scanner, file_path, model_copy)
 
             return web.json_response({
                 'success': True,

tests/services/test_check_pending_models.py

@@ -363,6 +363,148 @@ async def test_check_pending_models_handles_corrupted_progress_file(
     assert result["pending_count"] == 1
 
 
+@pytest.mark.asyncio
+@pytest.mark.usefixtures("tmp_path")
+async def test_check_pending_models_uses_bulk_folder_index_for_large_libraries(
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path,
+    settings_manager,
+):
+    """For >1000 candidates the pre-check scans the library root once instead of
+    probing every folder individually."""
+
+    ws_manager = RecordingWebSocketManager()
+    manager = download_module.DownloadManager(ws_manager=ws_manager)
+
+    monkeypatch.setitem(settings_manager.settings, "example_images_path", str(tmp_path))
+
+    # 1500 unprocessed models triggers the bulk lookup path
+    models = [
+        {"sha256": f"{i:064x}", "model_name": f"Model {i}"}
+        for i in range(1500)
+    ]
+
+    # Create folders with files for the first 500 models
+    for i in range(500):
+        model_dir = tmp_path / f"{i:064x}"
+        model_dir.mkdir()
+        (model_dir / "image_0.png").write_text("data")
+
+    _patch_scanners(monkeypatch, lora_scanner=StubScanner(models))
+
+    per_model_checks = 0
+
+    def counting_model_directory_has_files(path: str) -> bool:
+        nonlocal per_model_checks
+        per_model_checks += 1
+        return False
+
+    monkeypatch.setattr(
+        download_module,
+        "_model_directory_has_files",
+        counting_model_directory_has_files,
+    )
+
+    result = await manager.check_pending_models(["lora"])
+
+    assert result["success"] is True
+    assert result["total_models"] == 1500
+    assert result["pending_count"] == 1000
+    assert result["needs_download"] is True
+    # The per-folder check should not be used once we cross the threshold.
+    assert per_model_checks == 0
+
+
+@pytest.mark.asyncio
+@pytest.mark.usefixtures("tmp_path")
+async def test_check_pending_models_uses_per_folder_check_for_small_candidate_sets(
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path,
+    settings_manager,
+):
+    """For <=1000 candidates the pre-check keeps the accurate per-folder path."""
+
+    ws_manager = RecordingWebSocketManager()
+    manager = download_module.DownloadManager(ws_manager=ws_manager)
+
+    monkeypatch.setitem(settings_manager.settings, "example_images_path", str(tmp_path))
+
+    models = [
+        {"sha256": f"{i:064x}", "model_name": f"Model {i}"}
+        for i in range(500)
+    ]
+
+    # Create folders with files for the first 200 models
+    for i in range(200):
+        model_dir = tmp_path / f"{i:064x}"
+        model_dir.mkdir()
+        (model_dir / "image_0.png").write_text("data")
+
+    _patch_scanners(monkeypatch, lora_scanner=StubScanner(models))
+
+    per_model_checks = 0
+    original_has_files = download_module._model_directory_has_files
+
+    def counting_model_directory_has_files(path: str) -> bool:
+        nonlocal per_model_checks
+        per_model_checks += 1
+        return original_has_files(path)
+
+    monkeypatch.setattr(
+        download_module,
+        "_model_directory_has_files",
+        counting_model_directory_has_files,
+    )
+
+    result = await manager.check_pending_models(["lora"])
+
+    assert result["success"] is True
+    assert result["total_models"] == 500
+    assert result["pending_count"] == 300
+    assert result["needs_download"] is True
+    # Per-folder path should run once per candidate.
+    assert per_model_checks == 500
+
+
+@pytest.mark.asyncio
+@pytest.mark.usefixtures("tmp_path")
+async def test_check_pending_models_bulk_index_includes_legacy_folders(
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path,
+    settings_manager,
+):
+    """In multi-library mode the bulk index also scans the legacy root so models
+    whose folders have not been consolidated yet are not reported pending."""
+
+    ws_manager = RecordingWebSocketManager()
+    manager = download_module.DownloadManager(ws_manager=ws_manager)
+
+    monkeypatch.setitem(settings_manager.settings, "example_images_path", str(tmp_path))
+    monkeypatch.setitem(settings_manager.settings, "libraries", {"default": {}, "extra": {}})
+    monkeypatch.setitem(settings_manager.settings, "active_library", "extra")
+
+    # 1500 unprocessed models triggers the bulk lookup path
+    models = [
+        {"sha256": f"{i:064x}", "model_name": f"Model {i}"}
+        for i in range(1500)
+    ]
+
+    # Folders live at the LEGACY root/<hash> path (not yet consolidated)
+    for i in range(500):
+        model_dir = tmp_path / f"{i:064x}"
+        model_dir.mkdir()
+        (model_dir / "image_0.png").write_text("data")
+
+    _patch_scanners(monkeypatch, lora_scanner=StubScanner(models))
+
+    result = await manager.check_pending_models(["lora"])
+
+    assert result["success"] is True
+    assert result["total_models"] == 1500
+    assert result["pending_count"] == 1000
+    assert result["needs_download"] is True
+
+
 @pytest.fixture
 def settings_manager():
     return get_settings_manager()

tests/services/test_example_images_download_manager_async.py

@@ -26,6 +26,7 @@ class StubScanner:
 
     def __init__(self, models: list[dict]) -> None:
         self._cache = SimpleNamespace(raw_data=models)
+        self.sync_calls: list[tuple[str, dict]] = []
 
     async def get_cached_data(self):
         return self._cache
@@ -38,6 +39,14 @@ class StubScanner:
                 break
         return True
 
+    async def sync_cache_from_metadata(self, file_path: str, metadata: dict) -> bool:
+        self.sync_calls.append((file_path, metadata))
+        for index, model in enumerate(self._cache.raw_data):
+            if model.get("file_path") == metadata.get("file_path"):
+                self._cache.raw_data[index] = metadata
+                break
+        return True
+
 
 def _patch_scanner(monkeypatch: pytest.MonkeyPatch, scanner: StubScanner) -> None:
     async def _get_lora_scanner(cls):
@@ -588,6 +597,9 @@ async def test_not_found_example_images_are_cleaned(
     assert missing_url in downloader.calls
     assert manager._progress["failed_models"] == {model_hash}
     assert model_hash in manager._progress["processed_models"]
+    assert scanner.sync_calls
+    assert len(scanner.sync_calls) == 1
+    assert scanner.sync_calls[0][0] == str(model_path)
 
     remaining_images = model_metadata["civitai"]["images"]
     assert remaining_images == [

tests/utils/test_example_images_metadata.py

@@ -15,6 +15,7 @@ class StubScanner:
     def __init__(self, cache_items: List[Dict[str, Any]]) -> None:
         self.cache = SimpleNamespace(raw_data=cache_items)
         self.updates: List[Tuple[str, str, Dict[str, Any]]] = []
+        self.sync_updates: List[Tuple[str, Dict[str, Any]]] = []
 
     async def get_cached_data(self):
         return self.cache
@@ -23,6 +24,10 @@ class StubScanner:
         self.updates.append((old_path, new_path, metadata))
         return True
 
+    async def sync_cache_from_metadata(self, file_path: str, metadata: Dict[str, Any]) -> bool:
+        self.sync_updates.append((file_path, metadata))
+        return True
+
 
 @pytest.fixture(autouse=True)
 def patch_metadata_manager(monkeypatch: pytest.MonkeyPatch):
@@ -83,7 +88,7 @@ async def test_update_metadata_after_import_enriches_entries(monkeypatch: pytest
     assert custom[0]["type"] == "image"
 
     assert Path(patch_metadata_manager[0][0]) == model_file
-    assert scanner.updates
+    assert scanner.sync_updates
 
 
 @pytest.mark.asyncio
@@ -151,8 +156,8 @@ async def test_update_metadata_after_import_preserves_existing_metadata(
     assert saved_payload["civitai"]["trainedWords"] == ["foo"]
     assert {entry["id"] for entry in saved_payload["civitai"]["customImages"]} == {"existing-id", "new-id"}
 
-    assert scanner.updates
+    assert scanner.sync_updates
-    updated_metadata = scanner.updates[-1][2]
+    updated_metadata = scanner.sync_updates[-1][1]
     assert updated_metadata["civitai"]["images"] == existing_payload["civitai"]["images"]
     assert {entry["id"] for entry in updated_metadata["civitai"]["customImages"]} == {"existing-id", "new-id"}