⚡ Bolt: [성능 개선] SQLite WAL PRAGMA 중복 실행 제거

.jules/bolt.md

@@ -1,3 +1,7 @@
+## 2026-07-06 - [Optimize SQLite WAL PRAGMA for short-lived connections]
+**Learning:** SQLite's `PRAGMA journal_mode=WAL` is persistent per database file. In applications with many short-lived connections, executing it redundantly on every connection introduces unnecessary overhead.
+**Action:** Execute `PRAGMA journal_mode=WAL` once during initialization (e.g., via `conn.executescript()` with the schema) rather than on every new 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

@@ -12,3 +12,6 @@
 ### Fixed
 - 단일·일괄 대상 크기 입력을 비웠을 때 이전 custom validity와 `aria-invalid` 상태를 즉시 초기화해 현재 필수 입력 상태를 정확히 전달합니다.
 - 업로드 파일명의 경로 구분자를 정규화하여 POSIX에서도 Windows 형식의 클라이언트 경로가 일관된 basename으로 기록되도록 수정했습니다.
+
+### 성능 개선
+- `job_store.py` 및 `usage_metering.py`에서 매번 실행되던 `PRAGMA journal_mode=WAL` 구문을 데이터베이스 초기화 시에만 한 번 실행하도록 최적화하여 시스템 호출 및 쿼리 오버헤드를 줄였습니다.

job_store.py

@@ -95,7 +95,7 @@ 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(f"PRAGMA journal_mode=WAL;\n{_SCHEMA}")
 
     @contextmanager
     def _connect(self) -> Iterator[sqlite3.Connection]:
@@ -108,7 +108,6 @@ def _connect(self) -> Iterator[sqlite3.Connection]:
         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:

usage_metering.py

@@ -120,8 +120,7 @@ def __init__(self, db_path: str | Path) -> None:
         self._db_path = path
         self._lock = threading.Lock()
         with closing(self._connect()) as conn:
-            with conn:
-                conn.execute(_SCHEMA)
+            conn.executescript(f"PRAGMA journal_mode=WAL;\n{_SCHEMA}")
 
     def _connect(self) -> sqlite3.Connection:
         """Open a new short-lived connection with WAL mode enabled.
@@ -130,7 +129,6 @@ def _connect(self) -> sqlite3.Connection:
             A fresh :class:`sqlite3.Connection` to the store's database.
         """
         conn = sqlite3.connect(self._db_path, timeout=30.0)
-        conn.execute("PRAGMA journal_mode=WAL")
         return conn
 
     def record(