Change default handoffConditionTimeout to 15 minutes.#14539
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gianm merged 4 commits intoapache:masterfrom Jul 13, 2023
Merged
Change default handoffConditionTimeout to 15 minutes.#14539gianm merged 4 commits intoapache:masterfrom
gianm merged 4 commits intoapache:masterfrom
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Most of the time, when handoff is taking this long, it's because something is preventing Historicals from loading new data. In this case, we have two choices: 1) Stop making progress on ingestion, wait for Historicals to load stuff, and keep the waiting-for-handoff segments available on realtime tasks. (handoffConditionTimeout = 0, the current default) 2) Continue making progress on ingestion, by exiting the realtime tasks that were waiting for handoff. Once the Historicals get their act together, the segments will be loaded, as they are still there on deep storage. They will just not be continuously available. (handoffConditionTimeout > 0) I believe most users would prefer [2], because [1] risks ingestion falling behind the stream, which causes many other problems. It can cause data loss if the stream ages-out data before we have a chance to ingest it. Due to the way tuningConfigs are serialized -- defaults are baked into the serialized form that is written to the database -- this default change will not change anyone's existing supervisors. It will take effect for newly created supervisors.
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Thinking a bit about this change and discussing it with @kfaraz, it probably is ok to make this change. Initially, I was worried about this leading to holes in the data and recovery. But since it's only the hand-off, those holes will be temporary since the segment has been created. |
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A couple of minor nits.
Co-authored-by: Katya Macedo <38017980+ektravel@users.noreply.github.com>
Co-authored-by: Katya Macedo <38017980+ektravel@users.noreply.github.com>
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* Change default handoffConditionTimeout to 15 minutes. Most of the time, when handoff is taking this long, it's because something is preventing Historicals from loading new data. In this case, we have two choices: 1) Stop making progress on ingestion, wait for Historicals to load stuff, and keep the waiting-for-handoff segments available on realtime tasks. (handoffConditionTimeout = 0, the current default) 2) Continue making progress on ingestion, by exiting the realtime tasks that were waiting for handoff. Once the Historicals get their act together, the segments will be loaded, as they are still there on deep storage. They will just not be continuously available. (handoffConditionTimeout > 0) I believe most users would prefer [2], because [1] risks ingestion falling behind the stream, which causes many other problems. It can cause data loss if the stream ages-out data before we have a chance to ingest it. Due to the way tuningConfigs are serialized -- defaults are baked into the serialized form that is written to the database -- this default change will not change anyone's existing supervisors. It will take effect for newly created supervisors. * Fix tests. * Update docs/development/extensions-core/kafka-supervisor-reference.md Co-authored-by: Katya Macedo <38017980+ektravel@users.noreply.github.com> * Update docs/development/extensions-core/kinesis-ingestion.md Co-authored-by: Katya Macedo <38017980+ektravel@users.noreply.github.com> --------- Co-authored-by: Katya Macedo <38017980+ektravel@users.noreply.github.com>
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Most of the time, when handoff is taking this long, it's because something is preventing Historicals from loading new data. In this case, we have two choices:
Stop making progress on ingestion, wait for Historicals to load stuff,
and keep the waiting-for-handoff segments available on realtime tasks.
(handoffConditionTimeout = 0, the current default)
Continue making progress on ingestion, by exiting the realtime tasks
that were waiting for handoff. Once the Historicals get their act
together, the segments will be loaded, as they are still there on
deep storage. They will just not be continuously available.
(handoffConditionTimeout > 0)
I believe most users would prefer [2], because [1] risks ingestion falling behind the stream, which causes many other problems. It can cause data loss if the stream ages-out data before we have a chance to ingest it.
Due to the way tuningConfigs are serialized -- defaults are baked into the serialized form that is written to the database -- this default change will not change anyone's existing supervisors. It will take effect for newly created supervisors.