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z/TPF Guaranteed Delivery DF queue support (APAR PJ46377)

  
With APAR PJ45923, IBM provided the initial support for Guaranteed Delivery for JVM, using MQ as the underlying transport mechanism.   While MQ provides a flexible option and some management capabilities, performance testing indicated some issues scaling up to higher message rates (>6,000 msgs / sec at 4k message sizes).

z/TPF Guaranteed Delivery DF queue support provides support for an underlying DF database as the transport mechanism.  This support is specifically targeted towards smaller message sizes (< 4k ) so that the data can reside entirely with a fixed file record (without using pools).  Larger messages can be used with the DF queue support, but may result in significant pool usage.   Scale testing in house showed that we can achieve 30,000 msgs / sec at 4k message sizes, which is close to the theoretical maximum that can be sent with our current 1Gb OSA card.  We expected running on 10Gb OSA card the support would be able to scale past 30,000 msgs/sec.  These results were measured with the DF record id defined as a VFA delay file candidate as well as processor locking.

For more details about PJ46377, see the APEDIT.