Use direct PostgreSQL connections instead of pool to fix init deploy.

Co-authored-by: Cursor <cursoragent@cursor.com>

db_conn.py

@@ -17,15 +17,12 @@ DB_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "futures.db")
 
 _backend_lock = threading.Lock()
 _backend: Optional[str] = None
-_pg_pool = None
-_pg_pool_lock = threading.Lock()
 
 try:
     import psycopg
     from psycopg import OperationalError as PgOperationalError
     from psycopg import IntegrityError as PgIntegrityError
     from psycopg.rows import dict_row
-    from psycopg_pool import ConnectionPool
 
     _PSYCOPG_OK = True
 except ImportError:
@@ -33,7 +30,6 @@ except ImportError:
     PgOperationalError = Exception  # type: ignore[misc,assignment]
     PgIntegrityError = Exception  # type: ignore[misc,assignment]
     dict_row = None  # type: ignore[assignment]
-    ConnectionPool = None  # type: ignore[misc,assignment]
     _PSYCOPG_OK = False
 
 OperationalError = sqlite3.OperationalError
@@ -52,7 +48,7 @@ def db_backend() -> str:
         if url.startswith(("postgresql://", "postgres://")):
             if not _PSYCOPG_OK:
                 raise RuntimeError(
-                    "已配置 DATABASE_URL 但未安装 psycopg，请执行: pip install 'psycopg[binary]' psycopg-pool"
+                    "已配置 DATABASE_URL 但未安装 psycopg，请执行: pip install 'psycopg[binary]'"
                 )
             _backend = "postgres"
         else:
@@ -216,16 +212,6 @@ class DbConnection:
         self._conn.rollback()
 
     def close(self) -> None:
-        if self._backend == "postgres" and self._from_pool:
-            try:
-                self._conn.rollback()
-            except Exception:
-                pass
-            try:
-                self._conn.close()
-            except Exception:
-                pass
-            return
         try:
             self._conn.close()
         except Exception:
@@ -248,38 +234,18 @@ class DbConnection:
         self.close()
 
 
-def _pg_pool_instance() -> ConnectionPool:
-    global _pg_pool
-    if _pg_pool is not None:
-        return _pg_pool
-    with _pg_pool_lock:
-        if _pg_pool is not None:
-            return _pg_pool
-        url = (os.getenv("DATABASE_URL") or "").strip()
-        min_size = max(1, int(os.getenv("PG_POOL_MIN", "2") or 2))
-        max_size = max(min_size, int(os.getenv("PG_POOL_MAX", "20") or 20))
-        _pg_pool = ConnectionPool(
-            conninfo=url,
-            min_size=min_size,
-            max_size=max_size,
-            kwargs={"row_factory": dict_row},
-            open=True,
-        )
-        return _pg_pool
-
-
 def connect_db(path: str | None = None) -> DbConnection:
-    """获取数据库连接。PostgreSQL 使用连接池；SQLite 每次新建连接（WAL）。"""
+    """获取数据库连接。PostgreSQL / SQLite 均为每次新建连接（用毕 close）。"""
     if is_postgres():
-        pool = _pg_pool_instance()
-        raw = pool.getconn()
+        url = (os.getenv("DATABASE_URL") or "").strip()
+        raw = psycopg.connect(url, row_factory=dict_row)
         try:
             with raw.cursor() as cur:
                 cur.execute("SET TIME ZONE 'Asia/Shanghai'")
             raw.commit()
         except Exception:
             pass
-        return DbConnection("postgres", raw, from_pool=True)
+        return DbConnection("postgres", raw, from_pool=False)
 
     db_path = path or DB_PATH
     raw = sqlite3.connect(db_path, timeout=30, check_same_thread=False)
@@ -293,11 +259,8 @@ def connect_db(path: str | None = None) -> DbConnection:
 
 
 def close_pg_pool() -> None:
-    global _pg_pool
-    with _pg_pool_lock:
-        if _pg_pool is not None:
-            _pg_pool.close()
-            _pg_pool = None
+    """兼容旧调用；当前 PostgreSQL 使用直连，无全局连接池。"""
+    return
 
 
 def execute_retry(
@@ -365,8 +328,8 @@ def is_db_contention_error(exc: BaseException) -> bool:
 
 
 def reset_backend_for_tests(backend: str | None = None) -> None:
-    """测试用：重置后端检测与连接池。"""
-    global _backend, _pg_pool
+    """测试用：重置后端检测。"""
+    global _backend
     close_pg_pool()
     with _backend_lock:
         _backend = backend