[NIFI-9391] MergeRecord does not work in stateless flows

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.16.0
• Component/s: Extensions
• Labels: stateless
• Assignee: Peter Turcsanyi
• Reporter: Peter Turcsanyi
• Created: 18/Nov/21 15:45
• Updated: 21/Mar/22 20:38
• Resolved: 04/Jan/22 16:37

Description

The stateless runtime triggers a processor up until FFs are available in the upstream queue.

MergeRecord needs an extra onTrigger() call where session.get() yields no result in order to get notified that no more FFs are available and it is time to send the merged FF downstream. This extra call will never happen in stateless environment and MergeRecord cannot send out FF in this way.

Modify MergeRecord to run session.get() in a loop within a single onTrigger() call like MergeContent does:

while (binManager.getBinCount() <= context.getProperty(MAX_BIN_COUNT).asInteger()) {
    if (!isScheduled()) {
        break;
    }

    final ProcessSession session = sessionFactory.createSession();
    final List<FlowFile> flowFiles = session.get(1000);
    if (flowFiles.isEmpty()) {
        break;
    }
    ... 

NIFI-9390 also affects MergeContent when it is not in the starting position in the flow but this jira needs to be fixed first (otherwise the other cannot pop up).

Issue Links

• links to: GitHub Pull Request #5550