Incorrect rows in inline fetch result (#479)

* Raised error when incorrect Row offset it returned

* Changed error type

* grammar fix

* Added unit tests and modified the code

* Updated error message

* Updated the non retying to only inline case

* Updated fix

* Changed the flow

* Minor update

* Updated the retryable condition

* Minor test fix

* Added extra space

Author: jprakash-db

src/databricks/sql/client.py

@@ -808,6 +808,7 @@ def execute(
             self.thrift_backend,
             self.buffer_size_bytes,
             self.arraysize,
+            self.connection.use_cloud_fetch,
         )
 
         if execute_response.is_staging_operation:
@@ -1202,6 +1203,7 @@ def __init__(
         thrift_backend: ThriftBackend,
         result_buffer_size_bytes: int = DEFAULT_RESULT_BUFFER_SIZE_BYTES,
         arraysize: int = 10000,
+        use_cloud_fetch: bool = True,
     ):
         """
         A ResultSet manages the results of a single command.
@@ -1223,6 +1225,7 @@ def __init__(
         self.description = execute_response.description
         self._arrow_schema_bytes = execute_response.arrow_schema_bytes
         self._next_row_index = 0
+        self._use_cloud_fetch = use_cloud_fetch
 
         if execute_response.arrow_queue:
             # In this case the server has taken the fast path and returned an initial batch of
@@ -1250,6 +1253,7 @@ def _fill_results_buffer(self):
             lz4_compressed=self.lz4_compressed,
             arrow_schema_bytes=self._arrow_schema_bytes,
             description=self.description,
+            use_cloud_fetch=self._use_cloud_fetch,
         )
         self.results = results
         self.has_more_rows = has_more_rows

src/databricks/sql/thrift_backend.py

@@ -321,7 +321,7 @@ def _handle_request_error(self, error_info, attempt, elapsed):
 
     # FUTURE: Consider moving to https://github.com/litl/backoff or
     # https://github.com/jd/tenacity for retry logic.
-    def make_request(self, method, request):
+    def make_request(self, method, request, retryable=True):
         """Execute given request, attempting retries when
             1. Receiving HTTP 429/503 from server
             2. OSError is raised during a GetOperationStatus
@@ -460,7 +460,7 @@ def attempt_request(attempt):
         #       return on success
         #       if available: bounded delay and retry
         #       if not: raise error
-        max_attempts = self._retry_stop_after_attempts_count
+        max_attempts = self._retry_stop_after_attempts_count if retryable else 1
 
         # use index-1 counting for logging/human consistency
         for attempt in range(1, max_attempts + 1):
@@ -1028,6 +1028,7 @@ def fetch_results(
         lz4_compressed,
         arrow_schema_bytes,
         description,
+        use_cloud_fetch=True,
     ):
         assert op_handle is not None
 
@@ -1044,10 +1045,11 @@ def fetch_results(
             includeResultSetMetadata=True,
         )
 
-        resp = self.make_request(self._client.FetchResults, req)
+        # Fetch results in Inline mode with FETCH_NEXT orientation are not idempotent and hence not retried
+        resp = self.make_request(self._client.FetchResults, req, use_cloud_fetch)
         if resp.results.startRowOffset > expected_row_start_offset:
-            logger.warning(
-                "Expected results to start from {} but they instead start at {}".format(
+            raise DataError(
+                "fetch_results failed due to inconsistency in the state between the client and the server. Expected results to start from {} but they instead start at {}, some result batches must have been skipped".format(
                     expected_row_start_offset, resp.results.startRowOffset
                 )
             )

tests/unit/test_fetches.py

@@ -66,6 +66,7 @@ def fetch_results(
             lz4_compressed,
             arrow_schema_bytes,
             description,
+            use_cloud_fetch=True,
         ):
             nonlocal batch_index
             results = FetchTests.make_arrow_queue(batch_list[batch_index])