[NIFI-13914] Stateless not honoring ProcessSession.transfer ordering

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-M1, 2.0.0-M2, 2.0.0-M3, 2.0.0-M4
• Fix Version/s: 2.0.0
• Component/s: Core Framework
• Assignee: Mark Payne
• Reporter: Mark Payne
• Created: 21/Oct/24 18:57
• Updated: 21/Oct/24 20:39
• Resolved: 21/Oct/24 20:39

Description

Occasionally a Processor operates on a batch of FlowFiles instead of a single FlowFile. If it transfers the FlowFiles in a particular order, the Process Session is not honoring that ordering in stateless, which can result in the next processor receiving the data in the wrong order. For example, a source Processor might receive two FlowFiles in a single session and transfer the first, then the second, using `ProcessSession.transfer(FlowFile, Relationship)`. In this case, the ProcessSession properly updates the last queue date/index. But when the FlowFiles are transferred to the next StatelessFlowFileQueue, they are not provided in any particular order, and the stateless flowfile queue simply adds them in whatever order the given Collection iterates over them. This results in data being improperly re-ordered within a Stateless execution.

Issue Links

• links to: GitHub Pull Request #9432