Fix tx modes

Author: vgvoleg

tests/test_connections.py

@@ -30,29 +30,24 @@ def _test_isolation_level_read_only(
         cursor = connection.cursor()
         with suppress(dbapi.DatabaseError):
             maybe_await(cursor.execute("DROP TABLE foo"))
-
         cursor = connection.cursor()
         maybe_await(cursor.execute(
             "CREATE TABLE foo(id Int64 NOT NULL, PRIMARY KEY (id))"
         ))
 
         connection.set_isolation_level(isolation_level)
         cursor = connection.cursor()
-
         query = "UPSERT INTO foo(id) VALUES (1)"
         if read_only:
             with pytest.raises(dbapi.DatabaseError):
                 maybe_await(cursor.execute(query))
-
         else:
             maybe_await(cursor.execute(query))
 
         maybe_await(connection.rollback())
 
         connection.set_isolation_level("AUTOCOMMIT")
-
         cursor = connection.cursor()
-
         maybe_await(cursor.execute("DROP TABLE foo"))
 
     def _test_connection(self, connection: dbapi.Connection) -> None:
@@ -211,7 +206,9 @@ def connect() -> dbapi.AsyncConnection:
         try:
             yield conn
         finally:
-            await greenlet_spawn(conn.close)
+            def close() -> None:
+                maybe_await(conn.close())
+            await greenlet_spawn(close)
 
     @pytest.mark.asyncio
     @pytest.mark.parametrize(

ydb_dbapi/connections.py

@@ -30,26 +30,24 @@ class IsolationLevel(str, Enum):
 
 
 class _IsolationSettings(NamedTuple):
-    ydb_mode: ydb.BaseQueryTxMode
+    ydb_mode: ydb.BaseQueryTxMode | None
     interactive: bool
 
 
 _ydb_isolation_settings_map = {
-    IsolationLevel.AUTOCOMMIT: _IsolationSettings(
-        ydb.QuerySerializableReadWrite(), interactive=False
-    ),
+    IsolationLevel.AUTOCOMMIT: _IsolationSettings(None, interactive=False),
     IsolationLevel.SERIALIZABLE: _IsolationSettings(
         ydb.QuerySerializableReadWrite(), interactive=True
     ),
     IsolationLevel.ONLINE_READONLY: _IsolationSettings(
-        ydb.QueryOnlineReadOnly(), interactive=True
+        ydb.QueryOnlineReadOnly(), interactive=False
     ),
     IsolationLevel.ONLINE_READONLY_INCONSISTENT: _IsolationSettings(
         ydb.QueryOnlineReadOnly().with_allow_inconsistent_reads(),
-        interactive=True,
+        interactive=False,
     ),
     IsolationLevel.STALE_READONLY: _IsolationSettings(
-        ydb.QueryStaleReadOnly(), interactive=True
+        ydb.QueryStaleReadOnly(), interactive=False
     ),
     IsolationLevel.SNAPSHOT_READONLY: _IsolationSettings(
         ydb.QuerySnapshotReadOnly(), interactive=True
@@ -78,10 +76,11 @@ def __init__(
 
         self.connection_kwargs: dict = kwargs
 
-        self._tx_mode: ydb.BaseQueryTxMode = ydb.QuerySerializableReadWrite()
+        self._shared_session_pool: bool = False
+
         self._tx_context: TxContext | AsyncTxContext | None = None
+        self._tx_mode: ydb.BaseQueryTxMode | None = None
         self.interactive_transaction: bool = False
-        self._shared_session_pool: bool = False
 
         if ydb_session_pool is not None:
             self._shared_session_pool = True
@@ -99,21 +98,24 @@ def __init__(
         self._session: ydb.QuerySession | ydb.aio.QuerySession | None = None
 
     def set_isolation_level(self, isolation_level: IsolationLevel) -> None:
-        ydb_isolation_settings = _ydb_isolation_settings_map[isolation_level]
         if self._tx_context and self._tx_context.tx_id:
             raise InternalError(
                 "Failed to set transaction mode: transaction is already began"
             )
+
+        ydb_isolation_settings = _ydb_isolation_settings_map[isolation_level]
+
+        self._tx_context = None
         self._tx_mode = ydb_isolation_settings.ydb_mode
         self.interactive_transaction = ydb_isolation_settings.interactive
 
     def get_isolation_level(self) -> str:
-        if self._tx_mode.name == ydb.QuerySerializableReadWrite().name:
-            if self.interactive_transaction:
-                return IsolationLevel.SERIALIZABLE
+        if self._tx_mode is None:
             return IsolationLevel.AUTOCOMMIT
+        if self._tx_mode.name == ydb.QuerySerializableReadWrite().name:
+            return IsolationLevel.SERIALIZABLE
         if self._tx_mode.name == ydb.QueryOnlineReadOnly().name:
-            if self._tx_mode.settings.allow_inconsistent_reads:
+            if self._tx_mode.allow_inconsistent_reads:
                 return IsolationLevel.ONLINE_READONLY_INCONSISTENT
             return IsolationLevel.ONLINE_READONLY
         if self._tx_mode.name == ydb.QueryStaleReadOnly().name:
@@ -123,6 +125,12 @@ def get_isolation_level(self) -> str:
         msg = f"{self._tx_mode.name} is not supported"
         raise NotSupportedError(msg)
 
+    def _maybe_init_tx(
+        self, session: ydb.QuerySession | ydb.aio.QuerySession
+    ) -> None:
+        if self._tx_context is None and self._tx_mode is not None:
+            self._tx_context = session.transaction(self._tx_mode)
+
 
 class Connection(BaseConnection):
     _driver_cls = ydb.Driver
@@ -154,10 +162,7 @@ def cursor(self) -> Cursor:
         if self._session is None:
             raise RuntimeError("Connection is not ready, use wait_ready.")
 
-        if self.interactive_transaction:
-            self._tx_context = self._session.transaction(self._tx_mode)
-        else:
-            self._tx_context = None
+        self._maybe_init_tx(self._session)
 
         self._current_cursor = self._cursor_cls(
             session=self._session,
@@ -281,10 +286,7 @@ def cursor(self) -> AsyncCursor:
         if self._session is None:
             raise RuntimeError("Connection is not ready, use wait_ready.")
 
-        if self.interactive_transaction:
-            self._tx_context = self._session.transaction(self._tx_mode)
-        else:
-            self._tx_context = None
+        self._maybe_init_tx(self._session)
 
         self._current_cursor = self._cursor_cls(
             session=self._session,