⚡ Bolt: [성능 개선] SQLite WAL 저널 모드 불필요한 재설정 제거

.jules/bolt.md

@@ -1,3 +1,7 @@
+## 2025-02-18 - Persistent SQLite PRAGMA journal_mode=WAL
+**Learning:** SQLite's `PRAGMA journal_mode=WAL` is persistent per database file. In an architecture with many short-lived connections, executing it redundantly on every connection adds significant overhead.
+**Action:** Execute `PRAGMA journal_mode=WAL` once during database initialization (e.g., via `conn.executescript()` alongside schema creation) instead of every time `_connect()` is called.
+
 ## 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.

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("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

@@ -121,7 +121,7 @@ def __init__(self, db_path: str | Path) -> None:
         self._lock = threading.Lock()
         with closing(self._connect()) as conn:
             with conn:
-                conn.execute(_SCHEMA)
+                conn.executescript("PRAGMA journal_mode=WAL;\n" + _SCHEMA)
 
     def _connect(self) -> sqlite3.Connection:
         """Open a new short-lived connection with WAL mode enabled.
@@ -130,7 +130,6 @@ 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(