[UIMA-4881] UIMA DUCC: Optimize JP handling of no work from the JD

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.1.0-Ducc
• Assignee: Jaroslaw Cwiklik
• Reporter: Jaroslaw Cwiklik
• Created: 31/Mar/16 13:19
• Updated: 31/Mar/16 18:57
• Resolved: 31/Mar/16 18:57

Description

When a JD returns no work, each worker JP thread sleeps for a bit and than asks JD again. At large scaleout many threads repeat this cycle causing the JD to spend a lot of time handling WI requests.
Modify the JP to use a single thread in each process to retry request for work. While a single thread repeatedly retries other threads block until:

1) Retry thread receives work item
2) JP terminates