ActiveVOS Dispatch Service. ActiveVOS 9.0+

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1 ActiveVOS Dispatch Service ActiveVOS 9.0+

2 Dispatch Service The Dispatch Service provides an enhanced degree of control and visibility over the workload associated with handling service requests within the ActiveVOS engine Control the maximum number of concurrently executing requests for a particular service, process group, tenant, or entire engine Buffer overflow requests to persistent queues for reliable delivery View live service-level execution statistics on the admin console Dynamically update configuration to tune performance and adapt to changing load Can be implemented without refactoring existing processes or introducing external JMS configurations Use Cases Client system issues 90,000 one-way process requests all at once to a single ActiveVOS server instance. Rather than try dispatch all of these requests immediately, store the requests and process them in volumes that can actually be handled by the server Process calls a back-end service where each request performs some heavy-duty processing on the remote system. If too many requests are issued at once, the back-end service goes down. Need to provide a way to limit the number of process instances that are calling the service simultaneously. 2

3 Monitoring Dispatch Services To monitor and manage services under dispatch control, navigate to Monitor->Dispatch Service Name link = displays configuration dialog Executing = number of requests currently executing Queued = number of requests currently queued Average Time = Average amount of time per request for process to reach a quiescent state Consumed = Total number of requests consumed and executed Rejected = Total number of requests that were rejected by the engine Status = current service status, either Active, Suspended, or Pending Delete Reset = resets historical counts and averages 3

4 Configuring Dispatch Services To view and configure the policy for a service, click the service name link to display a Dispatch Configuration dialog Current dispatch configuration values are displayed Suspend Resume execution allows you to temporarily stop dispatching new requests to the engine, then resume later Fields are editable and values may be applied dynamically by clicking the Update Configuration link at the bottom of the page Purge Queued Requests will delete all waiting requests from the queue Delete Configuration will remove this configuration. If there are requests still queued, the status will be tagged as Pending Delete. No new requests will be added, and the configuration will be removed once all old requests have been consumed. 4

5 Dispatch Service Architecture Too Many Requests to Handle all at once!!! Configure Dispatch Runtimes Engine Configuration Update Configuration Dispatch Manager BPEL Engine Process Execution Buffer Requests Runtime Queues Engine 1 Tenant 2 Group 3 Dispatch Runtimes Service 4 View Metrics Admin Console Dispatch Requests to the Engine 5

6 Handling Inbound Requests For each configuration created, the Dispatch Manager maintains a Dispatch Runtime for that configuration The Dispatch Runtime wraps and manages the service-level dispatch elements for a particular service: Configuration details Queue Management Execution statistics When the engine receives an inbound message request: If dispatch control is enabled, the Dispatch Manager will buffer the request for controlled execution through the runtime Dispatch control applies to all ALL inbound receives EXCEPT for sub-process invokes HTTP, JMS, Process invokes are buffered One-way and Request-Response are buffered 6

7 Controlling Concurrent Execution While the maximum number of requests are executing, other requests wait in the queue. New requests are dispatched to the engine as the processes kicked off by previous requests enter a quiescent state We determine that a process has gone quiescent as follows: Process has been released by the process manager and is eligible to leave memory Process is either in a final state, suspended, or running with no pending invoke activities running If a particular request is taking a long time for the process to go quiescent, the timeout value may kick in an allow another request to start nonetheless 7