esb_deploy - Progress Sonic ESB Deployment Guide 8.5 - Product ...

Chapter 6: Adapting Imported Services to a Domain
Setting the Number of Listener Threads
The number of listeners for a BPEL Service needs to account for the expected number of
concurrently active receives with corresponding replies. A receive with a corresponding
reply blocks the listener thread until the reply is produced. A single process could have
multiple receive/reply pairs; and could therefore block multiple listener threads. If there
aren't enough listeners available a process could deadlock. Asynchronous interactions
(one way with an invoke callback rather than a reply) do not tie up a listener thread.
The optimal number of threads is one more than the number of threads required by each
receive in a BPEL server instance times the number of allowed concurrent receives to the
instance. For example, if the developer notes that a BPEL Service requires two threads
and you expect no more than five receives to be running concurrently, set the number of
listener threads to eleven.
For more information, see the Progress Sonic Workbench User Guide in the Eclipse help.
Invoking a BPEL Service from an Itinerary using ESBPEL or ESBWS
A BPEL Service can be invoked from an itinerary using either an ESBPEL file or an
ESBWS file:
● Using an ESBPEL — Can invoke any process or partner link in a deployed BPAR. No
need for a public WSDL or any binding information. Script executes in the BPEL
Service on its listener thread.
● Using an ESBWS — Requires concrete port and binding information in the BPEL
Service's public WSDL. This WSDL must be authored (it is not generated). Script
executes on the caller's thread.
Tuning Classloader Memory
Each BPEL Service deployed to a container has a classloader that loads its classes first.
When you deploy multiple BPEL Services in one container, multiple copies of the same
classes are loaded in memory. You can set the -XX:MaxPermSize JVM option to specify a
larger memory allocation for class files.
136 Progress Sonic ESB Deployment Guide 8.5