⚡ Bolt: [성능 개선] SQLite WAL 모드 초기화 최적화

.jules/bolt.md

@@ -1,3 +1,7 @@
+## 2026-08-10 - [Persistent SQLite WAL Mode]
+**Learning:** SQLite's WAL journal mode (PRAGMA journal_mode=WAL) is persistent per database file. In applications creating many short-lived connections, executing it on every connection introduces unnecessary overhead.
+**Action:** Execute persistent PRAGMAs like journal_mode=WAL once during schema initialization (e.g., using conn.executescript) rather than repeatedly on every connection.
+
 ## 2024-05-28 - Avoid O(N^2) Path.resolve() in Batch Processing
 **Learning:** Python's `pathlib.Path.resolve()` is relatively slow because it touches the filesystem to follow symlinks and resolve relative paths. When dealing with a batch operation (e.g., scanning large directories of media files), calculating protected files via `any(target == src.resolve() for src in sources)` on every check leads to massive O(N^2) CPU overhead.
 **Action:** Pre-resolve the entire list of candidate paths once into a `frozenset` at the beginning of the batch process. Pass this resolved set down the call stack so that collision/protection checks become O(1) hash map lookups instead of triggering millions of unnecessary disk access operations.

CHANGELOG.md

@@ -11,3 +11,5 @@
 
 ### Fixed
 - 단일·일괄 대상 크기 입력을 비웠을 때 이전 custom validity와 `aria-invalid` 상태를 즉시 초기화해 현재 필수 입력 상태를 정확히 전달합니다.
+
+- `job_store.py`에서 매 연결마다 실행되던 SQLite `PRAGMA journal_mode=WAL` 구문을 스키마 초기화 시 한 번만 실행하도록 최적화하여 불필요한 오버헤드 감소

job_store.py

@@ -95,20 +95,19 @@ def __init__(self, db_path: str) -> None:
         self._db_path = str(db_path)
         self._lock = threading.Lock()
         with self._connect() as conn:
-            conn.execute(_SCHEMA)
+            conn.executescript("PRAGMA journal_mode=WAL;\n" + _SCHEMA)
 
     @contextmanager
     def _connect(self) -> Iterator[sqlite3.Connection]:
-        """Open a new WAL-mode connection to the underlying database.
+        """Open a new connection to the underlying database.
 
         Yields:
-            A short-lived ``sqlite3.Connection`` with WAL journaling and
-            a row factory that yields ``sqlite3.Row`` objects.
+            A short-lived ``sqlite3.Connection`` and a row factory that yields
+            ``sqlite3.Row`` objects.
         """
         conn = sqlite3.connect(self._db_path, timeout=30.0)
         try:
             conn.row_factory = sqlite3.Row
-            conn.execute("PRAGMA journal_mode=WAL")
             yield conn
             conn.commit()
         finally: