On Windows, shutil.rmtree() fails when deleting a directory that contains
an open SQLite database file. The ZIP update path in _download_and_replace_zip()
calls _clean_plugin_folder() which tries to delete the cache/ directory,
but downloaded_versions.sqlite is held open by DownloadedVersionHistoryService.
Fix:
- Add close() method to DownloadedVersionHistoryService to release
the persistent SQLite connection
- Call close() before _clean_plugin_folder() in the ZIP update flow
- Add 'cache' to the skip_files list so the runtime cache directory is
never deleted during plugin updates
The method mark_not_downloaded() was misleading — it doesn't negate
'downloaded' history (the model was indeed downloaded before), but
rather sets is_deleted_override = 1 to indicate the version was
downloaded and subsequently deleted. This flag allows re-download when
the 'skip previously downloaded' setting is enabled.
Rename to mark_as_deleted() to accurately reflect its semantics.
Root cause: 231 concurrent /check-model-exists requests on 175K-lora library
caused ~9.4s wall clock time. The bottleneck was two-fold:
1. DownloadedVersionHistoryService opened a new sqlite3.connect() for every
query under asyncio.Lock. With a large WAL from 175K entries, each
connect() took ~8ms. Serialized by the lock across 231 requests, the
230th request waited ~1848ms just for lock acquisition.
2. check_model_exists always queried download history even when the model
was found locally. The history result (hasBeenDownloaded /
downloadedVersionIds) is only used by the UI when the model is NOT
found locally; when found, the 'in library' indicator takes priority.
Changes:
- downloaded_version_history_service.py: added persistent _get_conn() that
creates the SQLite connection once and reuses it across all queries
- misc_handlers.py: early-return from check_model_exists when the model
exists locally, bypassing the history service entirely (lock skipped)
Expected: per-request wait time drops from ~1912ms to <3ms, wall clock
from ~9.4s to <0.3s for the 175K-lora user's 231-card page.
