Welcome!

Agile Computing Authors: Liz McMillan, Pat Romanski, Elizabeth White, Dana Gardner, Andy Thurai

Related Topics: Java IoT, Apache

Java IoT: Blog Feed Post

Stress & Load Testing Web Apps (Even ADF & Apex) Using Apache JMeter

I can't recommend enough the importance of stress testing your web applications

A couple of years ago I presented Take a load off! Load testing your Oracle Apex or JDeveloper web applications at OOW and AUSOUG. I can't recommend enough the importance of stress testing your web applications, it's saved my bacon a number of times. Frequently as developers, we develop under a single user (developer) model where concurrency issues are easily avoided. When our programs hit production, with just 1 more user, suddenly our programs grind to a halt or fall over in bizarre places. Result, pie on developers' faces, users' faith in new technologies destroyed, and general gnashing of teeth all round. Some simple stress and load tests can head off problems way before they hit production.

(For the remainder of this post I'll infer "stress testing" and "load testing" as the same thing, though strictly speaking one tests for your application falling over, and the other how fast it responds under load)

So how to go about stress testing a web application?

There are numerous tools available to stress test web applications, paid and free. This post will look at the setup and use of Apache's JMeter, my tool of choice, mainly because it is free! ... to undertake a very simple stress test. Apache JMeter is available here, version 2.3.3 at time of writing.

On starting JMeter (<jmeter-home>/bin/jmeter.bat on Windows) you'll see the following:

Creating a Thread Group
From here what we want to do is set up a Thread Group that simulates a number of users (concurrent sessions), done by right clicking the Test Plan node -> Thread Group option. This results in:


As you can see the Thread Group allows us to set a number of threads to simulate concurrent users/sessions, loop through tests and more.

Creating HTTP Requests
From here we can create a number of HTTP requests (Test Plan node right click -> Add -> Sampler -> HTTP Requests) to simulate each HTTP request operation (Get, Post etc), HTTP headers, payloads and more. However in a standard user session between server and browser there can be a huge array of these requests and configuring these HTTP requests within JMeter would be a major pain.

Configuring the HTTP Proxy Server

However there's an easier way. Apache JMeter can work as a proxy between your browser and server and record a user's HTTP session, namely the individual HTTP requests, that can be re-played in a JMeter Thread Group later.

To set this up instead right click the Workbench node, Add -> Non-Test Elements -> HTTP Proxy Server:


To configure the HTTP Proxy Server do the following:

* Port – set to a number that wont clash with an existing HTTP server on your PC (say 8085)
* Target Controller – set to "Test Plan > Thread Group". When the proxy server records the HTTP session between your browser and server, this setting implies the HTTP requests will be recorded against the Thread Group you created earlier, so we can reuse them later
* URL Patterns to include – a regular expression based string that tells the proxy server which URLs to record, and those to ignore. To capture everything set it to .* (dot star). Be warned that during recording however, if you use your browser for anything else but accessing the server you wish to stress test, JMeter will also capture that traffic. This includes periodic refreshes by web applications such as Gmail or Google Docs that you don't even initiate; I'm pretty sure when replaying your stress test, Google would prefer you not to stress test their infrastructure for them; stick to your own for now ;-)

The end HTTP Proxy Server setting will look something like this:


You'll note the HTTP Proxy Server has a Start button. We can't use this just yet.

Configuring your Browser
In order for the JMeter HTTP Proxy Server to capture the traffic between your server and browser, you need to make some changes to your browser's configuration. I'm assuming you're using Firefox 3 in the following example, but same approximate steps are needed for Internet Explorer.

Under Firefox open the Tools -> Options menu, then Advanced icon, Network tab, Settings button which will open the Connection Settings dialog.

In the Connection Settings dialog set the following:

* Select the Manual proxy configuration radio button
* HTTP Proxy – localhost
* Port – 8085 as per the JMeter HTTP Proxy Server option we set earlier
* No Proxy for – ensure that localhost and 127.0.0.1 aren't in the exclusion list


The above setup makes an assumption that the server you want to access is accessibly without a further external proxy required.


Recording your HTTP session
Once the browser's proxy is setup, to record a session between the browser and server do the following:

1) In Apache JMeter hit the Start button on the HTTP Proxy Server page
2) In your browser enter the URL of the first page in the application you want to stress test

Thereafter as you navigate your web application, enter data and so on, JMeter will faithfully record each HTTP request between the browser in server against your Thread Group. This may not be immediately obvious, but expand the Thread Group and you'll see each HTTP request made from the browser to server:


As can be seen, even visiting 1 web page can generate a huge amount of traffic. Ensure to stop recording the HTTP session by selecting the Stop button in the JMeter HTTP Proxy Server page.

Configuring the Thread Group for replay
Once you've recorded the session in the Thread Group there are a couple of extra things we need to achieve.

For web application's that use Cookies and session IDs (JDeveloper's ADF uses a JSessionID for tracking sessions) to track each unique user session, we cannot replay the exact HTTP request sequence with the server through JMeter, as the session ID is pegged to the recorded session, not the upcoming stress test sessions.

To solve this in JMeter right click the Thread Group -> Add -> Config Element -> HTTP Cookie Manager. This will be added as the last element to the Thread Group. I usually move it to the top of the tree:


Next we need to configure the Thread Group to show us the results of the stress test. There are a number of different ways to do this, from graphing the responses, to showing the raw HTTP responses. In this post we'll take the later option.

Right click the Thread Group -> Add -> Listener -> View Results in Tree, which will add a View Results in Tree node to the end of the Thread Group:


Finally save the Thread Group by selecting it in the node tree, then File -> Save.

Running the Thread Group
To commence your first stress test run, it's best to leave the number of spawned sessions to 1, just to see the overall test will work in it's most basic form. The default Thread Group number of threads is set to 1, so there is no need to make a change to do this.

To run the test, simply select the Run menu -> Start. On running the Thread Group, you'll see the top right of JMeter has a little box that tells if it's still running, and the number of tests to go vs total number of tests:


Once the tests are complete, this indicator will grey out.

We can now visit the View Results Tree:


This shows the HTTP requests that were sent out and on selecting an individual request, you see the raw HTTP request and the actual response. You'll note the small green triangles showing a successful HTTP 200 result. If different HTTP errors occur the triangles show different colours. Also remember that sometimes application errors don't perculate up to the HTTP layer in your web application, so you should check your application's logs too (in the case of a JEE application, this will be your container's internal logs).

Running a Stress Test
The obvious step from here is to change the Thread Group number of threads to a higher number.

From here take time out to explore the other features in JMeter. It includes a wide range of features that in particular make it useful for regression testing.

Caveats
Firstly remember when doing this you're not only stress testing your application, your stress testing a server, potentially stress testing databases, stress testing your networks and so on. Therefore you can have an affect on anybody sharing those resources. "Hard core" stress tests should be on separate infrastructure, after hours, aiming for as little impact on those around you!

Also keep in mind, besides seeing your application fall over at 2 users, 10 users, 100 users, which is an important test, try to be realistic about your stress tests. Stress testing you're brand-new-application to a 1 million concurrent users is probably not being realistic. How many concurrent user requests do you really expect and what response times do you need? Normally when I ask managers this question they'll answer with, "oh we have 1000 concurrent users, the application must support that many at any one time". However what they really mean is the application has 1000 users, potentially all logged into the application (ie. sessions) at the same time, but not necessarily hitting the server with HTTP requests at any onetime.

Read the original blog entry...

More Stories By Chris Muir

Chris Muir, an Oracle ACE Director, senior developer and trainer, and frequent blogger at http://one-size-doesnt-fit-all.blogspot.com, has been hacking away as an Oracle consultant with Australia's SAGE Computing Services for too many years. Taking a pragmatic approach to all things Oracle, Chris has more recently earned battle scars with JDeveloper, Apex, OID and web services, and has some very old war-wounds from a dark and dim past with Forms, Reports and even Designer 100% generation. He is a frequent presenter and contributor to the local Australian Oracle User Group scene, as well as a contributor to international user group magazines such as the IOUG and UKOUG.

IoT & Smart Cities Stories
The hierarchical architecture that distributes "compute" within the network specially at the edge can enable new services by harnessing emerging technologies. But Edge-Compute comes at increased cost that needs to be managed and potentially augmented by creative architecture solutions as there will always a catching-up with the capacity demands. Processing power in smartphones has enhanced YoY and there is increasingly spare compute capacity that can be potentially pooled. Uber has successfully ...
Cloud computing delivers on-demand resources that provide businesses with flexibility and cost-savings. The challenge in moving workloads to the cloud has been the cost and complexity of ensuring the initial and ongoing security and regulatory (PCI, HIPAA, FFIEC) compliance across private and public clouds. Manual security compliance is slow, prone to human error, and represents over 50% of the cost of managing cloud applications. Determining how to automate cloud security compliance is critical...
Enterprises have taken advantage of IoT to achieve important revenue and cost advantages. What is less apparent is how incumbent enterprises operating at scale have, following success with IoT, built analytic, operations management and software development capabilities - ranging from autonomous vehicles to manageable robotics installations. They have embraced these capabilities as if they were Silicon Valley startups.
Disruption, Innovation, Artificial Intelligence and Machine Learning, Leadership and Management hear these words all day every day... lofty goals but how do we make it real? Add to that, that simply put, people don't like change. But what if we could implement and utilize these enterprise tools in a fast and "Non-Disruptive" way, enabling us to glean insights about our business, identify and reduce exposure, risk and liability, and secure business continuity?
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound e...
Chris Matthieu is the President & CEO of Computes, inc. He brings 30 years of experience in development and launches of disruptive technologies to create new market opportunities as well as enhance enterprise product portfolios with emerging technologies. His most recent venture was Octoblu, a cross-protocol Internet of Things (IoT) mesh network platform, acquired by Citrix. Prior to co-founding Octoblu, Chris was founder of Nodester, an open-source Node.JS PaaS which was acquired by AppFog and ...
In today's enterprise, digital transformation represents organizational change even more so than technology change, as customer preferences and behavior drive end-to-end transformation across lines of business as well as IT. To capitalize on the ubiquitous disruption driving this transformation, companies must be able to innovate at an increasingly rapid pace.
Predicting the future has never been more challenging - not because of the lack of data but because of the flood of ungoverned and risk laden information. Microsoft states that 2.5 exabytes of data are created every day. Expectations and reliance on data are being pushed to the limits, as demands around hybrid options continue to grow.
"MobiDev is a Ukraine-based software development company. We do mobile development, and we're specialists in that. But we do full stack software development for entrepreneurs, for emerging companies, and for enterprise ventures," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
The explosion of new web/cloud/IoT-based applications and the data they generate are transforming our world right before our eyes. In this rush to adopt these new technologies, organizations are often ignoring fundamental questions concerning who owns the data and failing to ask for permission to conduct invasive surveillance of their customers. Organizations that are not transparent about how their systems gather data telemetry without offering shared data ownership risk product rejection, regu...