fix(sqllab): reinstate "Force trino client async execution" (apache#2…

…5680)

docs/docs/databases/installing-database-drivers.mdx

@@ -52,12 +52,12 @@ Some of the recommended packages are shown below. Please refer to [setup.py](htt
 | [Oracle](/docs/databases/oracle)                          | `pip install cx_Oracle`                                                            | `oracle://`                                                                                                 |
 | [PostgreSQL](/docs/databases/postgres)                    | `pip install psycopg2`                                                             | `postgresql://<UserName>:<DBPassword>@<Database Host>/<Database Name>`                                      |
 | [Presto](/docs/databases/presto)                          | `pip install pyhive`                                                               | `presto://`                                                                                                 |
-| [Rockset](/docs/databases/rockset)                        | `pip install rockset-sqlalchemy`                                                   | `rockset://<api_key>:@<api_server>`
+| [Rockset](/docs/databases/rockset)                        | `pip install rockset-sqlalchemy`                                                   | `rockset://<api_key>:@<api_server>`                                                                         |
 | [SAP Hana](/docs/databases/hana)                          | `pip install hdbcli sqlalchemy-hana or pip install apache-superset[hana]`          | `hana://{username}:{password}@{host}:{port}`                                                                |
 | [StarRocks](/docs/databases/starrocks)                    | `pip install starrocks`                                                            | `starrocks://<User>:<Password>@<Host>:<Port>/<Catalog>.<Database>`                                          |
 | [Snowflake](/docs/databases/snowflake)                    | `pip install snowflake-sqlalchemy`                                                 | `snowflake://{user}:{password}@{account}.{region}/{database}?role={role}&warehouse={warehouse}`             |
-| SQLite                                                    | No additional library needed                                                       | `sqlite://`                                                                                                 |
-| [SQL Server](/docs/databases/sql-server)                  | `pip install pymssql`                                                              | `mssql+pymssql://`                                                                                                  |
+| SQLite                                                    | No additional library needed                                                       | `sqlite://path/to/file.db?check_same_thread=false`                                                          |
+| [SQL Server](/docs/databases/sql-server)                  | `pip install pymssql`                                                              | `mssql+pymssql://`                                                                                          |
 | [Teradata](/docs/databases/teradata)                      | `pip install teradatasqlalchemy`                                                   | `teradatasql://{user}:{password}@{host}`                                                                    |
 | [TimescaleDB](/docs/databases/timescaledb)                | `pip install psycopg2`                                                             | `postgresql://<UserName>:<DBPassword>@<Database Host>:<Port>/<Database Name>`                               |
 | [Trino](/docs/databases/trino)                            | `pip install trino`                                                                | `trino://{username}:{password}@{hostname}:{port}/{catalog}`                                                 |

docs/docs/frequently-asked-questions.mdx

@@ -142,7 +142,7 @@ Another workaround is to change where superset stores the sqlite database by add
 `superset_config.py`:
 
 ```
-SQLALCHEMY_DATABASE_URI = 'sqlite:////new/location/superset.db'
+SQLALCHEMY_DATABASE_URI = 'sqlite:////new/location/superset.db?check_same_thread=false'
 ```
 
 You can read more about customizing Superset using the configuration file

docs/docs/installation/configuring-superset.mdx

@@ -45,7 +45,9 @@ SECRET_KEY = 'YOUR_OWN_RANDOM_GENERATED_SECRET_KEY'
 # superset metadata (slices, connections, tables, dashboards, ...).
 # Note that the connection information to connect to the datasources
 # you want to explore are managed directly in the web UI
-SQLALCHEMY_DATABASE_URI = 'sqlite:////path/to/superset.db'
+# The check_same_thread=false property ensures the sqlite client does not attempt
+# to enforce single-threaded access, which may be problematic in some edge cases
+SQLALCHEMY_DATABASE_URI = 'sqlite:////path/to/superset.db?check_same_thread=false'
 
 # Flask-WTF flag for CSRF
 WTF_CSRF_ENABLED = True

superset/config.py

@@ -184,7 +184,10 @@ def _try_json_readsha(filepath: str, length: int) -> str | None:
 SECRET_KEY = os.environ.get("SUPERSET_SECRET_KEY") or CHANGE_ME_SECRET_KEY
 
 # The SQLAlchemy connection string.
-SQLALCHEMY_DATABASE_URI = "sqlite:///" + os.path.join(DATA_DIR, "superset.db")
+SQLALCHEMY_DATABASE_URI = (
+    f"""sqlite:///{os.path.join(DATA_DIR, "superset.db")}?check_same_thread=false"""
+)
+
 # SQLALCHEMY_DATABASE_URI = 'mysql://myapp@localhost/myapp'
 # SQLALCHEMY_DATABASE_URI = 'postgresql://root:password@localhost/myapp'
 

superset/db_engine_specs/base.py

@@ -1066,6 +1066,24 @@ def handle_cursor(cls, cursor: Any, query: Query, session: Session) -> None:
         query object"""
         # TODO: Fix circular import error caused by importing sql_lab.Query
 
+    @classmethod
+    def execute_with_cursor(
+        cls, cursor: Any, sql: str, query: Query, session: Session
+    ) -> None:
+        """
+        Trigger execution of a query and handle the resulting cursor.
+
+        For most implementations this just makes calls to `execute` and
+        `handle_cursor` consecutively, but in some engines (e.g. Trino) we may
+        need to handle client limitations such as lack of async support and
+        perform a more complicated operation to get information from the cursor
+        in a timely manner and facilitate operations such as query stop
+        """
+        logger.debug("Query %d: Running query: %s", query.id, sql)
+        cls.execute(cursor, sql, async_=True)
+        logger.debug("Query %d: Handling cursor", query.id)
+        cls.handle_cursor(cursor, query, session)
+
     @classmethod
     def extract_error_message(cls, ex: Exception) -> str:
         return f"{cls.engine} error: {cls._extract_error_message(ex)}"

superset/db_engine_specs/trino.py

@@ -18,6 +18,8 @@
 
 import contextlib
 import logging
+import threading
+import time
 from typing import Any, TYPE_CHECKING
 
 import simplejson as json
@@ -151,14 +153,21 @@ def get_tracking_url(cls, cursor: Cursor) -> str | None:
 
     @classmethod
     def handle_cursor(cls, cursor: Cursor, query: Query, session: Session) -> None:
-        if tracking_url := cls.get_tracking_url(cursor):
-            query.tracking_url = tracking_url
+        """
+        Handle a trino client cursor.
+
+        WARNING: if you execute a query, it will block until complete and you
+        will not be able to handle the cursor until complete. Use
+        `execute_with_cursor` instead, to handle this asynchronously.
+        """
 
         # Adds the executed query id to the extra payload so the query can be cancelled
-        query.set_extra_json_key(
-            key=QUERY_CANCEL_KEY,
-            value=(cancel_query_id := cursor.stats["queryId"]),
-        )
+        cancel_query_id = cursor.query_id
+        logger.debug("Query %d: queryId %s found in cursor", query.id, cancel_query_id)
+        query.set_extra_json_key(key=QUERY_CANCEL_KEY, value=cancel_query_id)
+
+        if tracking_url := cls.get_tracking_url(cursor):
+            query.tracking_url = tracking_url
 
         session.commit()
 
@@ -173,6 +182,51 @@ def handle_cursor(cls, cursor: Cursor, query: Query, session: Session) -> None:
 
         super().handle_cursor(cursor=cursor, query=query, session=session)
 
+    @classmethod
+    def execute_with_cursor(
+        cls, cursor: Any, sql: str, query: Query, session: Session
+    ) -> None:
+        """
+        Trigger execution of a query and handle the resulting cursor.
+
+        Trino's client blocks until the query is complete, so we need to run it
+        in another thread and invoke `handle_cursor` to poll for the query ID
+        to appear on the cursor in parallel.
+        """
+        execute_result: dict[str, Any] = {}
+
+        def _execute(results: dict[str, Any]) -> None:
+            logger.debug("Query %d: Running query: %s", query.id, sql)
+
+            # Pass result / exception information back to the parent thread
+            try:
+                cls.execute(cursor, sql)
+                results["complete"] = True
+            except Exception as ex:  # pylint: disable=broad-except
+                results["complete"] = True
+                results["error"] = ex
+
+        execute_thread = threading.Thread(target=_execute, args=(execute_result,))
+        execute_thread.start()
+
+        # Wait for a query ID to be available before handling the cursor, as
+        # it's required by that method; it may never become available on error.
+        while not cursor.query_id and not execute_result.get("complete"):
+            time.sleep(0.1)
+
+        logger.debug("Query %d: Handling cursor", query.id)
+        cls.handle_cursor(cursor, query, session)
+
+        # Block until the query completes; same behaviour as the client itself
+        logger.debug("Query %d: Waiting for query to complete", query.id)
+        while not execute_result.get("complete"):
+            time.sleep(0.5)
+
+        # Unfortunately we'll mangle the stack trace due to the thread, but
+        # throwing the original exception allows mapping database errors as normal
+        if err := execute_result.get("error"):
+            raise err
+
     @classmethod
     def prepare_cancel_query(cls, query: Query, session: Session) -> None:
         if QUERY_CANCEL_KEY not in query.extra:

superset/sql_lab.py

@@ -191,7 +191,7 @@ def get_sql_results(  # pylint: disable=too-many-arguments
                 return handle_query_error(ex, query, session)
 
 
-def execute_sql_statement(  # pylint: disable=too-many-arguments,too-many-statements
+def execute_sql_statement(  # pylint: disable=too-many-arguments
     sql_statement: str,
     query: Query,
     session: Session,
@@ -271,10 +271,7 @@ def execute_sql_statement(  # pylint: disable=too-many-arguments,too-many-statem
             )
         session.commit()
         with stats_timing("sqllab.query.time_executing_query", stats_logger):
-            logger.debug("Query %d: Running query: %s", query.id, sql)
-            db_engine_spec.execute(cursor, sql, async_=True)
-            logger.debug("Query %d: Handling cursor", query.id)
-            db_engine_spec.handle_cursor(cursor, query, session)
+            db_engine_spec.execute_with_cursor(cursor, sql, query, session)
 
         with stats_timing("sqllab.query.time_fetching_results", stats_logger):
             logger.debug(

tests/unit_tests/db_engine_specs/test_trino.py

@@ -352,7 +352,7 @@ def test_handle_cursor_early_cancel(
     query_id = "myQueryId"
 
     cursor_mock = engine_mock.return_value.__enter__.return_value
-    cursor_mock.stats = {"queryId": query_id}
+    cursor_mock.query_id = query_id
     session_mock = mocker.MagicMock()
 
     query = Query()
@@ -366,3 +366,32 @@ def test_handle_cursor_early_cancel(
         assert cancel_query_mock.call_args[1]["cancel_query_id"] == query_id
     else:
         assert cancel_query_mock.call_args is None
+
+
+def test_execute_with_cursor_in_parallel(mocker: MockerFixture):
+    """Test that `execute_with_cursor` fetches query ID from the cursor"""
+    from superset.db_engine_specs.trino import TrinoEngineSpec
+
+    query_id = "myQueryId"
+
+    mock_cursor = mocker.MagicMock()
+    mock_cursor.query_id = None
+
+    mock_query = mocker.MagicMock()
+    mock_session = mocker.MagicMock()
+
+    def _mock_execute(*args, **kwargs):
+        mock_cursor.query_id = query_id
+
+    mock_cursor.execute.side_effect = _mock_execute
+
+    TrinoEngineSpec.execute_with_cursor(
+        cursor=mock_cursor,
+        sql="SELECT 1 FROM foo",
+        query=mock_query,
+        session=mock_session,
+    )
+
+    mock_query.set_extra_json_key.assert_called_once_with(
+        key=QUERY_CANCEL_KEY, value=query_id
+    )

tests/unit_tests/sql_lab_test.py

@@ -55,8 +55,8 @@ def test_execute_sql_statement(mocker: MockerFixture, app: None) -> None:
     )
 
     database.apply_limit_to_sql.assert_called_with("SELECT 42 AS answer", 2, force=True)
-    db_engine_spec.execute.assert_called_with(
-        cursor, "SELECT 42 AS answer LIMIT 2", async_=True
+    db_engine_spec.execute_with_cursor.assert_called_with(
+        cursor, "SELECT 42 AS answer LIMIT 2", query, session
     )
     SupersetResultSet.assert_called_with([(42,)], cursor.description, db_engine_spec)
 
@@ -106,10 +106,8 @@ def test_execute_sql_statement_with_rls(
         101,
         force=True,
     )
-    db_engine_spec.execute.assert_called_with(
-        cursor,
-        "SELECT * FROM sales WHERE organization_id=42 LIMIT 101",
-        async_=True,
+    db_engine_spec.execute_with_cursor.assert_called_with(
+        cursor, "SELECT * FROM sales WHERE organization_id=42 LIMIT 101", query, session
     )
     SupersetResultSet.assert_called_with([(42,)], cursor.description, db_engine_spec)