feat(csharp): integrate straggler mitigation into CloudFetchDownloader #42
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CloudFetchDownloader Integration: - Background monitoring thread runs every 5 seconds - Per-file CancellationTokenSource for clean cancellation - Automatic retry mechanism for cancelled stragglers - Metrics tracking for all active downloads - Sequential fallback mode support - Thread-safe metrics and cancellation token management Implementation only - tests in next PR. Builds on: stack/straggler-detector
This was referenced Nov 17, 2025
jadewang-db
requested changes
Nov 17, 2025
| // Straggler mitigation fields | ||
| private readonly bool _isStragglerMitigationEnabled; | ||
| private readonly StragglerDownloadDetector? _stragglerDetector; | ||
| private readonly ConcurrentDictionary<long, FileDownloadMetrics>? _activeDownloadMetrics; |
Collaborator
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should make these part of the detector for better class isolation design. and use event notificaiton to the download detector for reporting
| var config = stragglerConfig ?? CloudFetchStragglerMitigationConfig.Disabled; | ||
| _isStragglerMitigationEnabled = config.Enabled; | ||
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| if (config.Enabled) |
Collaborator
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again, this logic should in the detector and if not enabled, the detector should just return nothing
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| _cancellationTokenSource?.Cancel(); | ||
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| // Stop straggler monitoring if running |
Collaborator
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can we move this to the straggler detector?
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| */ | ||
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Collaborator
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overall feedback on this file, the change in this file should be minimal, it should just get a download failure with a reason of straggler download detection and retry. rest of the logic should be handled by the straggler download detector
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🥞 Stacked PR
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Summary
Integrates straggler mitigation components into
CloudFetchDownloader. Implementation only - tests in next PR.CloudFetchDownloader Integration:
CancellationTokenSourcefor clean cancellation of individual downloadsFileDownloadMetricsConcurrentDictionaryand atomic operationsKey Implementation Details:
FetchResultscallCode Changes:
_stragglerMitigationConfigfieldStragglerDownloadDetectorwhen enabled_activeDownloadMetricsdictionary for tracking_perFileCancellationTokensfor individual cancellation_isSequentialModeflag and counterMonitorForStragglers()background threadDownloadFileAsync()to track metrics and respect per-file CTSDispose()