Web services are developed and deployed based on standards provided by
the Web Services for Java 2 Platform, Enterprise Edition (J2EE) specification,
as is the mechanism used to access a Web service. This article explains performance
considerations for Web services supported by this specification.
When you develop or deploy a Web service, several artifacts are required,
including a Web Services Description Language (WSDL) file. The WSDL file describes
the format and syntax of the Web service input and output SOAP messages. When
a Web service is implemented in the WebSphere Application Service runtime,
the SOAP message is translated based on the J2EE request. The J2EE-based response
is then translated back to a SOAP message.
The most critical performance consideration is the translation between
the XML-based SOAP message and the Java object. Performance is high for a
Web service implementation in WebSphere Application Server, however, application
design, deployment and tuning can be improved. See Monitoring
the performance of Web services applications for more information about
analyzing and tuning Web services.
If you are using Web service application that was developed for a WebSphere
Application Server version prior to Version 6.0, you can achieve better performance
by running the wsdeploy command. The wsdeploy command regenerates
Web services artifact classes to increase the serialization and deserialization
performance.
Basic considerations for a high-performance Web services application
The
following are basic considerations you should know when designing a Web services
application:
- Reduce the Web services requests by using a few highly functional APIs,
rather than several simple APIs.
- Design your WSDL file interface to limit the size and complexity of SOAP
messages.
- Use the document/literal style argument when you generate the WSDL file.
- Leverage the caching capabilities offered for WebSphere Application Server.
- Test the performance of your Web service.
Additional Web services performance features that you can
leverage
- In-process optimizations for Web services to optimize communication path
between a Web services client application and a Web container that are located
in the same application server process. For details and enabling this feature
see Web services client to Web container optimized
communication
- Access to Web services over multiple transport protocols extends existing
JAX-RPC capabilities to support non-SOAP bindings such as RMI/IIOP and JMS.
These alternative transports can improve performance and quality of service
aspects for Web services. For more detailed information see RMI-IIOP
using JAX-RPC.
- The SOAP with Attachments API for Java (SAAJ) 1.2 provides a low-level
programming model for Web services relative to JAX-RPC. The SAAJ 1.2 API provides
features to create and process SOAP requests using a low-level XML API. SAAJ
1.2 supports just-in-time parsing and other internal algorithms. For information
about SAAJ 1.2 or Web services programming see SOAP
with Attachments API for Java.
- The Web services tooling generates higher performance custom deserializers
for all JAX-RPC beans. Redeploying a V5.x application into the V6 runtime
can decrease the processing time for large messages.
- Serialization and deserialization runtime is enhanced to cache frequently
used serializers and deserializers. This can decrease the processing time
for large messages.
- The performance of WS-security encryption and digital signature validation
is improved because of the use of the SAAJ 1.2 implementation.
IBM provides considerable documentation and best practices for Web services
application design and development that details these items and more. For
a list of key Web sites that discuss performance best practices, see Web services: Resources for learning.