Click here to close now.

Welcome!

Websphere Authors: Jayaram Krishnaswamy, Pat Romanski, Elizabeth White, Kevin Benedict, Carmen Gonzalez

Related Topics: Websphere

Websphere: Article

Caching In

Expediting content delivery with the dynamic cache service

The quest for increased application performance is a science in itself. IBM WebSphere Application Server includes a powerful caching technology called the dynamic cache service, which you can employ in your Web applications to dramatically improve performance.

In this article, we'll use the dynamic cache service to increase the performance of a simple Web application. We will then use Apache JMeter, an open source load generator, to load-test our cached application in order to measure the application performance gains achieved by leveraging the dynamic cache service.

As you will see, the potential performance gains realized by using the dynamic cache service can be achieved with minimal effort. No changes to your application code are required, which means there is no impact on application portability.

The dynamic cache service is the name given to a set of services provided by WebSphere Application Server. The types of caching services include servlet and JSP caching, a Java object cache facility, a cache for Web services, and a command cache. In this introductory article our example will focus on the use of the servlet and JSP caching facility.

Enter Stage Left - Our Application to Tweak
Our demonstration application is implemented as a servlet that fetches a large piece of content from a remote HTTP server, then performs some text processing and returns the result to the end user. Our servlet grabs content from the Gutenberg Web site, which hosts downloadable books in ASCII format (www.gutenberg.net). For those unfamiliar with the Gutenberg project, this site hosts downloadable books that have expired copyrights and are therefore freely available.

Our example servlet will perform some text processing on the downloaded book: it will italicize the introductory section in the book's text that describes the Gutenberg project. We will test the performance before and after turning on caching and then compare the results. Once caching is enabled, the book will be downloaded on the first servlet request and presented to the user. Subsequent servlet requests will be served from the cache.

The servlet code (see Listing 1) is simple and straightforward, and uses standard Java packages and classes to read, parse, and transmit the content.

The servlet opens a URL connection to a book on gutenberg.net (see Figure 1) and copies the output to the servlet's output stream. The first section of the book contains the Gutenberg preamble (disclaimers and such), which the servlet puts in italics. Once the servlet reaches the end of the preamble (marked in the text stream with "*END*" at the end of a line), the servlet stops italicizing and switches to a more readable font for books (Times). The servlet also logs how long it took to produce the result, which has the side effect of showing us when the servlet is called (versus served from the cache). This will be handy once we enable caching because the log will show that WebSphere is using the cached result and bypassing the servlet call completely.

You can download an EAR file containing the servlet and test the performance on your own system. The source code for this article can be downloaded from www.sys-con.com/websphere/sourcec.cfm.

To see the effect of using dynamic caching in our application, we'll juxtapose the performance of our application with and without caching enabled. To study our application's performance, we'll leverage Apache JMeter. It is beyond the scope of this article to delve into the details of how to use JMeter, but you can learn more about how to use JMeter at www.devx.com/webdev/Article/17950/0. JMeter allows us to simulate a load of requests against our application server and measure subsequent performance.

We used JMeter v1.9.1 from http://jakarta.apache.org/jmeter. Our test environment consisted of one machine running WebSphere Studio Advanced Edition 5.0.1 with the WebSphere v5.0 Test Environment on a Windows 2000 Pro machine configured with a single AMD 3000+ processor and 1GB of RAM. We ran JMeter on the same machine. Since this example is "I/O-bound," running JMeter on another machine does not significantly affect performance. We used WebSphere Application Server 5.0.1, but other versions will yield similar results.

We configured JMeter with a "Jakarta Users" thread group, using 5 threads and 100 iterations (see Figure 2).

Under the thread group we added an HTTP request to access our servlet. We used port 9080 to access our servlet's Web container directly (see Figure 3). Figure 4 shows the results of our baseline (precache) test.

It's not too surprising that the average servlet response time is almost 15 seconds; it takes time to process and transmit 901K of text. Because each request takes so long (by design), our throughput is a mere 18.7 requests per minute. Our next step is to enable the dynamic cache service and measure the performance improvement.

Enabling the Dynamic Cache Service in WebSphere Application Server
Enable the dynamic cache service in the WebSphere administrative console as follows: open the administrative console, click Servers > Application Servers in the navigation tree, click on your server, and select Dynamic Cache Service under Additional Properties. Select Enable service at server startup in the Startup state field and click OK.

Enable servlet caching as follows: in the administrative console, click Servers > Application Servers in the navigation tree, select your server, and click Web Container. Check the Enable servlet caching checkbox under the Configuration tab. Click Apply or OK.

To complete the configuration changes, click Save on the top menu bar, click the Save button, and then restart the application server.

Configuring Our Servlet to Use Dynamic Cache
To specify the cache settings for our servlet, we created a cachespec.xml file (see Listing 2), located in the WEB-INF subdirectory of our WAR file. Let's take some time to discuss some of the cache settings in this file.

  • sharing-policy: We set this to shared-pull, which means that the cached data will be shared across nodes in a clustered environment, and that each node will have to pull (request) the data from other nodes. The other options are not-shared, shared-push, shared-pull, and a hybrid mode called shared-push-pull. These options are described in detail in the WebSphere Application Server InfoCenter.
  • name: This is the URI of the servlet to cache; it can be relative to the Web application context root, as is ours.
  • cache-id: This section describes how WebSphere should build the unique identifiers' cache entries. The components of the cache ID serve as rules that the cache manager uses to build a key value. For servlets, there are nine types of components that you can use to build a cache ID construction rule, giving you rich control over what content in your application is cached. In our example, we used components consisting of any parameters passed in on the servlet request, the URI path, plus a header field called "host" in the request. At least one of these components must be non-empty, otherwise the dynamic cache service will simply not cache the data for that request.
  • timeout: By specifying a time-to-live value of 0, we specify that we want our cache entry to live indefinitely. Specifying a positive number would define the number of seconds we want the cache entry to exist in our cache.

    We have only scratched the surface of the configuration parameters you can set for a cacheable object. For example, you can opt to persist cache entries to disk in case of overflows or the housing server being stopped. Refer to the WebSphere Information Center (www-306.ibm.com/software/webservers/appserv/infocenter.html) to find out more information about which parameters can be used to achieve the desired caching effect you'd like to associate with a specific cacheable object. These design considerations are of course specific to your enterprise application's business requirements.

    The WebSphere Application Server continually monitors the cachspec.xml file for changes, so the changes will take place immediately when you save the file. You therefore don't need to restart your enterprise application or application server when you want to make adjustments to your caching strategy.

    The Performance Gain with the Dynamic Caching Service Enabled
    Once we saved our cachespec.xml file in the WEB-INF directory, WebSphere Application Server noticed the new file, and wrote the following line to System.out:

    [2/2/04 17:09:50:812 CST] 435b6a5a ConfigManager I DYNA0047I: Successfully loaded
    cache configuration file k:\wsad\workspace5\Dynamic Cache Example\Web
    Content\WEB-INF/cachespec.xml.

    Then we reran our JMeter test. Figure 5 shows the results.

    We started with a throughput of 18.7 transactions per minute, and with cachspec.xml in place we were able to achieve quite a bit more: 568 transactions per minute. The average time to serve a request went from 14.9 seconds down to a speedy 0.416 seconds. The dramatic improvement demonstrates the power of using WebSphere's dynamic caching service.

    Our test servlet was deliberately constructed to demonstrate a dramatic effect, but most Web applications that do any processing or back-end calls will benefit substantially from using the dynamic cache service. It's important to point out that we didn't need to make any changes to our servlet code. We simply created a cachespec.xml file in our WEB-INF directory and witnessed an immediate performance improvement.

    WebSphere Application Server 5.0 ships with a Cache Monitor application (see Figure 6) that allows you to use a Web browser to view reports on cache statistics, and also allows you do things like view the cache IDs of objects in the cache.

    The Cache Monitor is located in the <WAS_ROOT>/installableApps directory (CacheMonitor.ear) and is easy to install and use. After you have installed the Cache Monitor enterprise application, open the URL: http://<your_server>:<your_port>/cachemonitor. You can use the Reset Statistics and Clear Cache buttons to clean out the cache and get ready for another load test after you tweak the caching policy settings in your cachespec.xml file. This saves time, since you won't have to restart the application server between load tests.

    Conclusion
    Java servlets and JavaServer Pages are typically used to present dynamic content to a Web site visitor. WebSphere Application Server's dynamic cache service can be used to serve requests for content from an in-memory cache. Servlet output is stored in memory, expediting delivery to the end user.

    In this article, you used the dynamic cache service offerings on a Web application and witnessed the added performance benefits using Apache JMeter. The process of enabling WebSphere Application Server's dynamic cache service and modifying your Web application to use dynamic caching is rather simple. Leveraging these highly configurable caching options should be a major consideration for organizations trying to squeeze the most performance out of their application servers. You can learn more about the dynamic cache service in the WebSphere Information Center.

    Resource:

  • Using the dynamic cache service to improve performance: Click Here !

    Acknowledgment
    The authors would like to thank Lisa Tomita for her review of this article.

  • More Stories By Kulvir Singh Bhogal

    Kulvir Singh Bhogal works as an IBM Software Services for WebSphere consultant, devising and implementing WebSphere-centric solutions at customer sites across the nation. He has over fifty patents pending in a myriad of technology areas. He can be reached at kbhogal@us.ibm.com

    More Stories By Brad Bouldin

    Brad Bouldin works as an IBM Portal specialist assisting customers with planning, architecting, and implementing e-business solutions.

    Comments (2) View Comments

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    Most Recent Comments
    Carlos Melvin 04/14/04 05:24:26 PM EDT

    I have been reading a little on dynamic cache service. I have yet to see any reference to a system other than Windows. Does this work on an AIX platform?

    Pierre Comtois 03/31/04 02:06:01 PM EST

    How would the cache work/react when using the same JSP as a template for dynamic data recovered from a DB. An application we implemented with older version of WAS involved using about 10 template JSPs and populated over 10000 different "pages" on-demand, a "page" being a template with simply different content. Each "page"''s content was retrieved by the servlet and command classes based on keys present on the URL.

    Thx ...

    @ThingsExpo Stories
    SYS-CON Events announced today that Site24x7, the cloud infrastructure monitoring service, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Site24x7 is a cloud infrastructure monitoring service that helps monitor the uptime and performance of websites, online applications, servers, mobile websites and custom APIs. The monitoring is done from 50+ locations across the world and from various wireless carriers, thus providing a global perspective of the end-user experience. Site24x7 supports monitoring H...
    Sonus Networks introduced the Sonus WebRTC Services Solution, a virtualized Web Real-Time Communications (WebRTC) offer, purpose-built for the Cloud. The WebRTC Services Solution provides signaling from WebRTC-to-WebRTC applications and interworking from WebRTC-to-Session Initiation Protocol (SIP), delivering advanced real-time communications capabilities on mobile applications and on websites, which are accessible via a browser.
    SYS-CON Events announced today that Intelligent Systems Services will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Established in 1994, Intelligent Systems Services Inc. is located near Washington, DC, with representatives and partners nationwide. ISS’s well-established track record is based on the continuous pursuit of excellence in designing, implementing and supporting nationwide clients’ mission-critical systems. ISS has completed many successful projects in Healthcare, Commercial, Manufacturing, ...
    SYS-CON Events announced today that B2Cloud, a provider of enterprise resource planning software, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. B2cloud develops the software you need. They have the ideal tools to help you work with your clients. B2Cloud’s main solutions include AGIS – ERP, CLOHC, AGIS – Invoice, and IZUM
    SYS-CON Events announced today that Tufin, the market-leading provider of Security Policy Orchestration Solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. As the market leader of Security Policy Orchestration, Tufin automates and accelerates network configuration changes while maintaining security and compliance. Tufin's award-winning Orchestration Suite™ gives IT organizations the power and agility to enforce security policy across complex, multi-vendor enterprise networks. With more than 1...
    SYS-CON Events announced today that Cloudian, Inc., the leading provider of hybrid cloud storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Cloudian, Inc., is a Foster City, California - based software company specializing in cloud storage software. The main product is Cloudian, an Amazon S3-compliant cloud object storage platform, the bedrock of cloud computing systems, that enables cloud service providers and enterprises to build reliable, affordable and scalable cloud storage solu...
    SYS-CON Events announced today that Gridstore™, the leader in hyper-converged infrastructure purpose-built to optimize Microsoft workloads, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Gridstore™ is the leader in hyper-converged infrastructure purpose-built for Microsoft workloads and designed to accelerate applications in virtualized environments. Gridstore’s hyper-converged infrastructure is the industry’s first all flash version of HyperConverged Appliances that include both compute and storag...
    Temasys has announced senior management additions to its team. Joining are David Holloway as Vice President of Commercial and Nadine Yap as Vice President of Product. Over the past 12 months Temasys has doubled in size as it adds new customers and expands the development of its Skylink platform. Skylink leads the charge to move WebRTC, traditionally seen as a desktop, browser based technology, to become a ubiquitous web communications technology on web and mobile, as well as Internet of Things compatible devices.
    SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada. Our partner network encompasses some 300 of the world's leading systems integrators and security s...
    “With easy-to-use SDKs for Atmel’s platforms, IoT developers can now reap the benefits of realtime communication, and bypass the security pitfalls and configuration complexities that put IoT deployments at risk,” said Todd Greene, founder & CEO of PubNub. PubNub will team with Atmel at CES 2015 to launch full SDK support for Atmel’s MCU, MPU, and Wireless SoC platforms. Atmel developers now have access to PubNub’s secure Publish/Subscribe messaging with guaranteed ¼ second latencies across PubNub’s 14 global points-of-presence. PubNub delivers secure communication through firewalls, proxy ser...
    SYS-CON Events announced today that On the Avenue Marketing Group, a sales and marketing firm that utilizes events to market and sell products to consumers, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. On the Avenue Marketing Group (OTA) is a sales and marketing firm that utilizes events to market and sell products to consumers. On behalf of our clients, we attend thousands of fairs, festivals, expos, concerts, conferences, and sporting events annually, helping them reach millions of individuals ...
    Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 16th Cloud Expo at the Javits Center in New York June 9-11 will find fresh new content in a new track called PaaS | Containers & Microservices Containers are not being considered for the first time by the cloud community, but a current era of re-consideration has pushed them to the top of the cloud agenda. With the launch of Docker's initial release in March of 2013, interest was revved up several notches. Then late last...
    “In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
    Health care systems across the globe are under enormous strain, as facilities reach capacity and costs continue to rise. M2M and the Internet of Things have the potential to transform the industry through connected health solutions that can make care more efficient while reducing costs. In fact, Vodafone's annual M2M Barometer Report forecasts M2M applications rising to 57 percent in health care and life sciences by 2016. Lively is one of Vodafone's health care partners, whose solutions enable older adults to live independent lives while staying connected to loved ones. M2M will continue to gr...
    SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
    SYS-CON Events announced today that Ciqada will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Ciqada™ makes it easy to connect your products to the Internet. By integrating key components - hardware, servers, dashboards, and mobile apps - into an easy-to-use, configurable system, your products can quickly and securely join the internet of things. With remote monitoring, control, and alert messaging capability, you will meet your customers' needs of tomorrow - today! Ciqada. Let your products take flight. For more inform...
    SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
    Dave will share his insights on how Internet of Things for Enterprises are transforming and making more productive and efficient operations and maintenance (O&M) procedures in the cleantech industry and beyond. Speaker Bio: Dave Landa is chief operating officer of Cybozu Corp (kintone US). Based in the San Francisco Bay Area, Dave has been on the forefront of the Cloud revolution driving strategic business development on the executive teams of multiple leading Software as a Services (SaaS) application providers dating back to 2004. Cybozu's kintone.com is a leading global BYOA (Build Your O...
    The best mobile applications are augmented by dedicated servers, the Internet and Cloud services. Mobile developers should focus on one thing: writing the next socially disruptive viral app. Thanks to the cloud, they can focus on the overall solution, not the underlying plumbing. From iOS to Android and Windows, developers can leverage cloud services to create a common cross-platform backend to persist user settings, app data, broadcast notifications, run jobs, etc. This session provides a high level technical overview of many cloud services available to mobile app developers, includi...
    SYS-CON Events announced today that BroadSoft, the leading global provider of Unified Communications and Collaboration (UCC) services to operators worldwide, has been named “Gold Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. BroadSoft is the leading provider of software and services that enable mobile, fixed-line and cable service providers to offer Unified Communications over their Internet Protocol networks. The Company’s core communications platform enables the delivery of a range of enterprise and consumer calling...