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https://issues.apache.org/jira/browse/FLINK-19113?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Piotr Nowojski updated FLINK-19113:
-----------------------------------
Priority: Not a Priority (was: Minor)
> Add support for checkpointing with selectable inputs
> ----------------------------------------------------
>
> Key: FLINK-19113
> URL: https://issues.apache.org/jira/browse/FLINK-19113
> Project: Flink
> Issue Type: Improvement
> Components: API / DataStream, Runtime / Checkpointing
> Affects Versions: 1.12.0
> Reporter: Roman Khachatryan
> Priority: Not a Priority
> Labels: auto-deprioritized-major, stale-minor
>
> Currently, there is a validation in StreamingJobGraphGenerator that fails if
> an operator implements InputSelectable and checkpointing is enabled.
>
> One issue when removing this validation is that with Unaligned checkpoints
> recovery would deadlock if there are records spanning multiple buffers.
> Consider the following case:
> - Two {{IntputGate}}s
> - Input selection is not ALL (say FIRST initially)
> - Unaligned Checkpoints ON
> - on recovery, there are "parts" of records in all channels (actually 1 is
> enough I think)
> On recovery,
> 1. {{StreamTask}} initiates recovery and scedule partition request upon it's
> end
> 2. All gates and channels will *receive* buffers from {{StateReader}}
> 3. All channels of a *single* gate will *consume* those state buffers -
> completing that gate's {{StateConsumedFuture}}
> 4. {{InputProcessor}} will return {{NOTHING_AVAILABLE}} (see
> {{StreamTwoInputProcessor.getInputStatus}})
> 5. {{StreamTask}} will suspend its default action
> 6. State of the 2nd gate won't be consumed - so its {{StateConsumedFuture}}s
> won't be completed - so no partitions will be requested (edited)
>
> A simple solution is to request partitions for each channel independently.
>
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