refactor(db)!: finalize pooled WNDB v2 migration

app/native/wndb/core/connection.py

@@ -11,6 +11,7 @@ from psycopg_pool import ConnectionPool
 from app.core.config import settings
 from app.infra.db.project_routing import get_project_pgconn_string
 
+_check_connection = ConnectionPool.check_connection
 _pools: OrderedDict[str, ConnectionPool] = OrderedDict()
 _pool_conninfo: dict[str, str] = {}
 _pool_borrows: dict[str, int] = {}
@@ -21,6 +22,10 @@ _active_project_connection: ContextVar[tuple[str, Connection] | None] = ContextV
     "wndb_active_project_connection",
     default=None,
 )
+_active_model_mutation_locks: ContextVar[frozenset[str]] = ContextVar(
+    "wndb_active_model_mutation_locks",
+    default=frozenset(),
+)
 
 
 def _close_pool(pool: ConnectionPool) -> None:
@@ -78,6 +83,7 @@ def get_project_pool(name: str) -> ConnectionPool:
             min_size=settings.PROJECT_PG_POOL_MIN_SIZE,
             max_size=settings.PROJECT_PG_POOL_SIZE + settings.PROJECT_PG_MAX_OVERFLOW,
             kwargs={"autocommit": True, "row_factory": dict_row},
+            check=_check_connection,
             open=True,
         )
         _pools[name] = pool
@@ -140,6 +146,7 @@ def get_admin_pool() -> ConnectionPool:
             min_size=settings.PROJECT_PG_POOL_MIN_SIZE,
             max_size=settings.PROJECT_PG_POOL_SIZE,
             kwargs={"autocommit": True, "row_factory": dict_row},
+            check=_check_connection,
             open=True,
         )
         _admin_pools[conninfo] = pool
@@ -192,10 +199,12 @@ def project_transaction(name: str) -> Iterator[Connection]:
     try:
         with pool.connection() as conn:
             token = _active_project_connection.set((name, conn))
+            lock_token = _active_model_mutation_locks.set(frozenset())
             try:
                 with conn.transaction():
                     yield conn
             finally:
+                _active_model_mutation_locks.reset(lock_token)
                 _active_project_connection.reset(token)
     finally:
         with _registry_lock:
@@ -208,6 +217,17 @@ def is_project_transaction_active(name: str) -> bool:
     return active is not None and active[0] == name
 
 
+def is_model_mutation_lock_active(name: str) -> bool:
+    """Return whether the current project transaction already owns its model lock."""
+    return name in _active_model_mutation_locks.get()
+
+
+def mark_model_mutation_lock_active(name: str) -> None:
+    """Record a transaction-scoped advisory lock to avoid duplicate round trips."""
+    locks = _active_model_mutation_locks.get()
+    _active_model_mutation_locks.set(locks | {name})
+
+
 @contextmanager
 def admin_connection() -> Iterator[Connection]:
     """Borrow a PostgreSQL administration connection from its pool."""