[NIFI-4028] Wait processor removes cache regardless of the remaing counter

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.0
• Fix Version/s: 1.4.0
• Component/s: Extensions
• Assignee: Pierre Villard
• Reporter: Koji Kawamura
• Created: 07/Jun/17 07:43
• Updated: 17/Aug/17 00:24
• Resolved: 17/Aug/17 00:24

Description

Current Wait processor implementation removes cache entry if it's configured with 'Releasable FlowFile Count' is one, when it finds a wait signal reaches to 'Target Signal Count' no matter how large the current count is.

This behavior can be problematic, when an user expects the same Signal Identifier to be released multiple FlowFiles one by one while multiple counts to be accumulated by Notify.

For example this scenario does not work:

1. Notify notifies to a 'signal-a' + 1 => 'signal-a' = 1
2. Notify notifies to a 'signal-a' again, +1 => 'signal-a' = 2
3. Wait releases 1 FlowFile, then remove the 'signal-a' => 'signal-a' is removed
4. Wait will not be able to release another FlowFile

This should be fixed as follows:

1. Notify notifies to a 'signal-a' + 1 => 'signal-a' = 1
2. Notify notifies to a 'signal-a' again, +1 => 'signal-a' = 2
3. Wait releases 1 FlowFile, then update the 'signal-a', -1 => 'signal-a' = 1
4. Wait releases another FlowFile, then 'signal-a' becomes 0, remove 'signal-a'

Issue Links

• links to: GitHub Pull Request #2055