Installing a second LoRA Manager instance (standalone or a second
ComfyUI install) that shares the settings directory puts two processes
on the same cache databases. Three things made that unsafe.
- The updater preserved cache/ and model_cache/ but not a legacy
recipe_cache/ directory, so a portable install predating the cache/
move lost its recipe database on a git-based update. Add it to
_PRESERVE_DIRS and to .gitignore.
- Cache connections used the sqlite3 default 5s timeout, which a
scanning instance can exceed, turning a concurrent write into
"database is locked". Route every shared cache connection through
connect_cache_db(), which raises the timeout to 30s and sets
busy_timeout + synchronous=NORMAL to match the existing WAL mode.
App-private databases (download queue, update history) are unchanged.
- A full-table cache replace is a read-modify-write that SQLite cannot
make atomic across processes, so two instances could interleave and
one snapshot could overwrite the other. Guard the recipe and model
save_cache paths with a cross-process advisory lock (flock on POSIX,
msvcrt on Windows). Locking is best-effort: if it is unavailable the
call proceeds and the SQLite busy timeout is the fallback.
The lock file is a hidden sibling of the database and is deliberately
never unlinked, so a second process cannot lock a fresh inode.
Will Miao