[SPARK-21145] Restarted queries reuse same StateStoreProvider, causing multiple concurrent tasks to update same StateStore

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Fix Version/s: 2.3.0
• Component/s: Structured Streaming
• Target Version/s: 2.3.0
• Assignee: Tathagata Das
• Reporter: Tathagata Das
• Created: 19/Jun/17 22:54
• Updated: 23/Jun/17 07:43
• Resolved: 23/Jun/17 07:43

Description

StateStoreProvider instances are loaded on-demand in a executor when a query is started. When a query is restarted, the loaded provider instance will get reused. Now, there is a non-trivial chance, that the task of the previous query run is still running, while the tasks of the restarted run has started. So for a stateful partition, there may be two concurrent tasks related to the same stateful partition, and there for using the same provider instance. This can lead to inconsistent results and possibly random failures, as state store implementations are not designed to be thread-safe.

Issue Links

• links to: [Github] Pull Request #18355 (tdas)
• links to: [Github] Pull Request #18396 (tdas)