OSB, Service Callouts and OQL – Part 1 by Vijay Kumar
By Juergenkress-Oracle on Jul 11, 2014
Oracle Fusion Middleware customers use Oracle Service Bus (OSB) for
virtualizing Service endpoints and implementing stateless service
orchestrations. Behind the performance and speed of OSB, there are a
couple of key design implementations that can affect application
performance and behavior under heavy load. One of the heavily used
feature in OSB is the Service Callout pipeline action for message
enrichment and invoking multiple services as part of one single
orchestration. Overuse of this feature, without understanding its
internal implementation, can lead to serious problems.
This post will delve into OSB internals, the problem associated with usage of Service Callout under high loads, diagnosing it via thread dump and heap dump analysis using tools like ThreadLogic and OQL (Object Query Language) and resolving it. The first section in the series will mainly cover the threading model used internally by OSB for implementing Route Vs. Service Callouts.
OSB Pipeline actions for Service Invocations
A Proxy is the inbound portion of OSB that can handle the incoming request, transform/validate/enrich/manipulate the payload before invoking co-located or remote services. The execution logic is built using the proxy pipeline actions. For executing the remote (or even local) business service, OSB provides three forms of service invocations within a Proxy pipeline:
- Route - invoke a single business service endpoint with (or without) a response. This happens entirely at end of a proxy service pipeline execution and bridges the request and response pipeline. The route can be treated as the logical destination to reach or final service invocation. There can be only one Route action (there can be choices of Route actions - but only one actual execution) in a given Proxy execution.
- Publish - invoke a business service without waiting for result or response (like 1-way). The caller does not care much about the response. Just interested in sending out something (and ensuring it reaches the other side).
- Service Callout - invoke one or more business service(s) as part of message augmentation or enrichment or validation but this is not the primary business service for a given Proxy, unlike the Route action. The service callouts can be equivalent to credit card validation, address verification while Route is equivalent to final order placement. There can be multiple Service Callouts inside a Proxy pipeline. Read the complete article here.
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