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Merged
shivam2680 merged 3 commits into from
Jul 28, 2025
Merged

added logs for cloud fetch speed #654

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13d13de
added logs for cloud fetch speed
shivam2680 Jul 26, 2025
4073d47
address commnets
shivam2680 Jul 28, 2025
a63fa28
fix unit test
shivam2680 Jul 28, 2025
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37 changes: 37 additions & 0 deletions src/databricks/sql/cloudfetch/downloader.py
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Original file line number Diff line number Diff line change
Expand Up @@ -51,12 +51,14 @@ class DownloadableResultSettings:
link_expiry_buffer_secs (int): Time in seconds to prevent download of a link before it expires. Default 0 secs.
download_timeout (int): Timeout for download requests. Default 60 secs.
max_consecutive_file_download_retries (int): Number of consecutive download retries before shutting down.
min_cloudfetch_download_speed (float): Threshold in MB/s below which to log warning. Default 0.1 MB/s.
"""

is_lz4_compressed: bool
link_expiry_buffer_secs: int = 0
download_timeout: int = 60
max_consecutive_file_download_retries: int = 0
min_cloudfetch_download_speed: float = 0.1


class ResultSetDownloadHandler:
Expand Down Expand Up @@ -90,6 +92,8 @@ def run(self) -> DownloadedFile:
self.link, self.settings.link_expiry_buffer_secs
)

start_time = time.time()

with self._http_client.execute(
method=HttpMethod.GET,
url=self.link.fileLink,
Expand All @@ -102,6 +106,13 @@ def run(self) -> DownloadedFile:

# Save (and decompress if needed) the downloaded file
compressed_data = response.content

# Log download metrics
download_duration = time.time() - start_time
self._log_download_metrics(
self.link.fileLink, len(compressed_data), download_duration
)

decompressed_data = (
ResultSetDownloadHandler._decompress_data(compressed_data)
if self.settings.is_lz4_compressed
Expand All @@ -128,6 +139,32 @@ def run(self) -> DownloadedFile:
self.link.rowCount,
)

def _log_download_metrics(
self, url: str, bytes_downloaded: int, duration_seconds: float
):
"""Log download speed metrics at INFO/WARN levels."""
# Calculate speed in MB/s (ensure float division for precision)
speed_mbps = (float(bytes_downloaded) / (1024 * 1024)) / duration_seconds

urlEndpoint = url.split("?")[0]
# INFO level logging
logger.info(
"CloudFetch download completed: %.4f MB/s, %d bytes in %.3fs from %s",
speed_mbps,
bytes_downloaded,
duration_seconds,
urlEndpoint,
)

# WARN level logging if below threshold
if speed_mbps < self.settings.min_cloudfetch_download_speed:
logger.warning(
"CloudFetch download slower than threshold: %.4f MB/s (threshold: %.1f MB/s) from %s",
speed_mbps,
self.settings.min_cloudfetch_download_speed,
url,
)

@staticmethod
def _validate_link(link: TSparkArrowResultLink, expiry_buffer_secs: int):
"""
Expand Down
23 changes: 21 additions & 2 deletions tests/unit/test_downloader.py
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,17 @@ class DownloaderTests(unittest.TestCase):
Unit tests for checking downloader logic.
"""

def _setup_time_mock_for_download(self, mock_time, end_time):
"""Helper to setup time mock that handles logging system calls."""
call_count = [0]
def time_side_effect():
call_count[0] += 1
if call_count[0] <= 2: # First two calls (validation, start_time)
return 1000
else: # All subsequent calls (logging, duration calculation)
return end_time
mock_time.side_effect = time_side_effect

@patch("time.time", return_value=1000)
def test_run_link_expired(self, mock_time):
settings = Mock()
Expand Down Expand Up @@ -75,13 +86,17 @@ def test_run_get_response_not_ok(self, mock_time):
d.run()
self.assertTrue("404" in str(context.exception))

@patch("time.time", return_value=1000)
@patch("time.time")
def test_run_uncompressed_successful(self, mock_time):
self._setup_time_mock_for_download(mock_time, 1000.5)

http_client = DatabricksHttpClient.get_instance()
file_bytes = b"1234567890" * 10
settings = Mock(link_expiry_buffer_secs=0, download_timeout=0, use_proxy=False)
settings.is_lz4_compressed = False
settings.min_cloudfetch_download_speed = 1.0
result_link = Mock(bytesNum=100, expiryTime=1001)
result_link.fileLink = "https://s3.amazonaws.com/bucket/file.arrow?token=abc123"

with patch.object(
http_client,
Expand All @@ -95,15 +110,19 @@ def test_run_uncompressed_successful(self, mock_time):

assert file.file_bytes == b"1234567890" * 10

@patch("time.time", return_value=1000)
@patch("time.time")
def test_run_compressed_successful(self, mock_time):
self._setup_time_mock_for_download(mock_time, 1000.2)

http_client = DatabricksHttpClient.get_instance()
file_bytes = b"1234567890" * 10
compressed_bytes = b'\x04"M\x18h@d\x00\x00\x00\x00\x00\x00\x00#\x14\x00\x00\x00\xaf1234567890\n\x00BP67890\x00\x00\x00\x00'

settings = Mock(link_expiry_buffer_secs=0, download_timeout=0, use_proxy=False)
settings.is_lz4_compressed = True
settings.min_cloudfetch_download_speed = 1.0
result_link = Mock(bytesNum=100, expiryTime=1001)
result_link.fileLink = "https://s3.amazonaws.com/bucket/file.arrow?token=xyz789"
with patch.object(
http_client,
"execute",
Expand Down
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