[UIMA-1799] UIMA AS should provide a way to increase prefetch size on a reply queue

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3AS
• Fix Version/s: 2.3.1AS
• Component/s: Async Scaleout
• Assignee: Jaroslaw Cwiklik
• Reporter: Jaroslaw Cwiklik
• Created: 04/Jun/10 13:58
• Updated: 15/Sep/10 18:50
• Resolved: 08/Jun/10 18:03

Description

UIMA AS currently provides no way to change prefetch size on a reply queue. A default of 1 is used. This slows down the rate of processing messages by a service. Each UIMA AS service has a dedicated submitter thread whose main job is to deliver a message to a thread pool for processing. Since the submitter thread executes very fast and the prefetch=1 , the submitter thread is constantly waiting for the Broker to deliver the next message. Increasing prefetch forces the Broker to deliver multiple messages to a service which buffers them until the submitter thread is ready. The size of the prefetch should be equal to a scalout factor defined on each reply queue. The default is still 1.

NOTE: increasing prefetch effects memory requirement for the service. The larger the prefetch the more messages are buffered taking up more memory.