[FLINK-21992] Fix availability notification in UnionInputGate

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 1.12.2, 1.13.0
• Fix Version/s: 1.13.0, 1.12.3
• Component/s: Runtime / Checkpointing
• Labels: pull-request-available
• Assignee: Arvid Heise
• Reporter: Arvid Heise
• Created: 26/Mar/21 10:24
• Updated: 22/Jun/21 14:07
• Resolved: 14/Apr/21 19:28

Description

A user on mailing list reported that his job gets stuck with unaligned checkpoint enabled.
http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Source-Operators-Stuck-in-the-requestBufferBuilderBlocking-tt42530.html

We received two similar reports in the past, but the users didn't follow up, so it was not as easy to diagnose as this time where the initial report already contains many relevant data points.

Beside a buffer leak, there could also be an issue with priority notification.

Issue Links

• links to: GitHub Pull Request #15586
• links to: GitHub Pull Request #15587