Welcome!

Open Web Authors: Carmen Gonzalez, Elizabeth White, Pat Romanski, PR.com Newswire, David Weinberger

Related Topics: Java, AJAX & REA

Java: Article

The Cost of an Exception

A closer look at the costs of throwing exceptions

Recently there was a bigger discussion at dynaTrace around the cost of exceptions. When working with customers we very often find a lot of exceptions they are not aware of. After removing these exceptions, the code runs significantly faster than before. This creates the assumption that using exceptions in your code comes with a significant performance overhead. The implication would be that you better avoid using exceptions. As exceptions are an important construct for handling error situation, avoiding exceptions completely does not seem to be good solution. All in all this was reason enough to have a closer look at the costs of throwing exceptions.

The Experiment
I based my experiment on a simple piece of code that randomly throws an exception. This is not a really scientifically-profound measurement and we also don’t know what the HotSpot compiler does with the code as it runs. Nevertheless it should provide us with some basic insights.

public class ExceptionTest {

public long maxLevel = 20;

public static void main (String ... args){

ExceptionTest test = new ExceptionTest();

long start = System.currentTimeMillis();
int count = 10000;
for (int i= 0; i < count; i++){
try {
test.doTest(2, 0);
}catch (Exception ex){
//        ex.getStackTrace();
}
}
long diff = System.currentTimeMillis() - start;
System.out.println(String.format("Average time for invocation: %1$.5f",((double) diff)/count));
}

public void doTest (int i, int level){
if (level < maxLevel){
try {
doTest (i, ++level);
}
catch (Exception ex){
//        ex.getStackTrace();
throw new RuntimeException ("UUUPS", ex);
}
}
else {
if (i > 1) {
throw new RuntimeException("Ups".substring(0, 3));
}
}
}
}

The Result
The result was very interesting. The cost of throwing and catching an exception seems to be rather low. In my sample it was about 0.002ms per Exception. This can more or less be neglected unless you really throw too many exceptions – and too many means we are talking about 100.000 or more.

While these results show that exception handling itself is not affecting code performance, it leaves open the question: what is responsible for the huge performance impact of exceptions? So obviously I was missing something – something important.

After thinking about it again, I realized that I was missing an important part of exception handling. I missed out the part on what you do when exceptions occur. In most cases you – hopefully – do not just catch the exception and that’s it. Normally you try to compensate for the problem and keep the application functioning for your end users. So the point I was missing was the compensation code that is executed for handling an exception. Depending on what this code is doing the performance penalty can become quite significant. In some cases this might mean retrying to connect to a server in other cases it might mean using a default fallback solution that is providing a far less-performing solution.

While this seemed to be a good explanation for the behavior we saw in many scenarios, I thought I am not done yet with the analysis. I had the feeling that there is something else that I was missing here.

Stack Traces
Still curious about this problem I looked into how the situation changes when I collect stack traces. This is what very often happens. You log an exception and its stack trace to try to figure out what the problem is.

I therefore modified my code to now get the stack trace of an exception as well. This changed the situation dramatically. Getting the stack trace of an exception had a 10x higher impact on the performance than just catching and throwing them. So while stack traces help to understand where and possibly also why a problem occurred, they come with a performance penalty.

The impact here is often very high as we are not talking about a single stack trace. In most cases exceptions are thrown – and caught – at multiple levels. Let us look at a simple example of a Web Service client connecting to a server. First there is an exception at the Java library level for the failed connection. Then there is a framework exception for the failed client and then there might be an application-level exception that some business logic invocation failed. This now sums up to three stack traces being collected.

In most cases you should see them in your log files or application output. Writing these potentially long stack traces again comes with some performance impact. At least you normally see and you can react to them if you look at your log files regularly – which is something you do, don’t you? ;-)

In some cases I have seen even worse behavior due to some incorrect logging code. Instead of checking whether a certain log level is enabled by calling log.isxxEnabled () first, developers just call logging methods. When this happens, logging code is always executed including getting stack traces of exceptions. As the log level however is set too low they never show up anywhere you might not even be aware of them. Checking for log levels first should be a general rule as it also avoids unnecessary object creation.

Conclusion
Not using exceptions because of their potential performance impact is a bad idea. Exceptions help to provide a uniform way to cope with runtime problems and they help to write clean code. You however need to trace the number of exceptions that are thrown in your code. Although they might be caught they can still have a significant performance impact. In dynaTrace we, by default, track thrown exceptions – and in many cases people are surprised by what is going on in their code and what the performance impact is in resolving them.

While exception usage is good you should avoid capturing too many stack traces. In many cases they are not even necessary to understand the problem – especially if they cover a problem you already expect. The exception message therefore might prove as being enough information. I get enough out of a Connection refused message so I do not need the full stack trace into the internal of the java.net call stack.

Related reading:

  1. Application Performance Monitoring in production – A Step-by-Step Guide – Part 1 // Setting up Application Performance Monitoring is a big task,...
  2. The impact of Garbage Collection on Java performance // In my last post I explained what a major...
  3. Top 10 Performance Problems taken from Zappos, Monster, Thomson and Co For a recent edition of the Swiss Computerworld Magazine we...
  4. Top 10 Client-Side Performance Problems in Web 2.0 Inspired by the Top 10 Performance Problems post which focuses...
  5. Real Life Ajax Troubleshooting Guide One of our clients occasionally runs into the following problem...

 

More Stories By Alois Reitbauer

Alois Reitbauer works as a Technology Strategist for dynaTrace Software where he is leading the Methods and Technology team. As part of the R&D team he influences the dynaTrace product strategy and works closely with key customers in implementing performance management solution for the entire lifecylce. Alois has 10 years experience as architect and developer in the Java and .NET space. He is a frequent speaker at technology conferences on performance and architecture related topics and regularly publishes articles blogs on blog.dynatrace.com

@ThingsExpo Stories
Software AG helps organizations transform into Digital Enterprises, so they can differentiate from competitors and better engage customers, partners and employees. Using the Software AG Suite, companies can close the gap between business and IT to create digital systems of differentiation that drive front-line agility. We offer four on-ramps to the Digital Enterprise: alignment through collaborative process analysis; transformation through portfolio management; agility through process automation and integration; and visibility through intelligent business operations and big data.
There will be 50 billion Internet connected devices by 2020. Today, every manufacturer has a propriety protocol and an app. How do we securely integrate these "things" into our lives and businesses in a way that we can easily control and manage? Even better, how do we integrate these "things" so that they control and manage each other so our lives become more convenient or our businesses become more profitable and/or safe? We have heard that the best interface is no interface. In his session at Internet of @ThingsExpo, Chris Matthieu, Co-Founder & CTO at Octoblu, Inc., will discuss how these devices generate enough data to learn our behaviors and simplify/improve our lives. What if we could connect everything to everything? I'm not only talking about connecting things to things but also systems, cloud services, and people. Add in a little machine learning and artificial intelligence and now we have something interesting...
Last week, while in San Francisco, I used the Uber app and service four times. All four experiences were great, although one of the drivers stopped for 30 seconds and then left as I was walking up to the car. He must have realized I was a blogger. None the less, the next car was just a minute away and I suffered no pain. In this article, my colleague, Ved Sen, Global Head, Advisory Services Social, Mobile and Sensors at Cognizant shares his experiences and insights.
We are reaching the end of the beginning with WebRTC and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) irreversibly encoded. In his session at Internet of @ThingsExpo, Peter Dunkley, Technical Director at Acision, will look at how this identity problem can be solved and discuss ways to use existing web identities for real-time communication.
Can call centers hang up the phones for good? Intuitive Solutions did. WebRTC enabled this contact center provider to eliminate antiquated telephony and desktop phone infrastructure with a pure web-based solution, allowing them to expand beyond brick-and-mortar confines to a home-based agent model. It also ensured scalability and better service for customers, including MUY! Companies, one of the country's largest franchise restaurant companies with 232 Pizza Hut locations. This is one example of WebRTC adoption today, but the potential is limitless when powered by IoT. Attendees will learn real-world benefits of WebRTC and explore future possibilities, as WebRTC and IoT intersect to improve customer service.
From telemedicine to smart cars, digital homes and industrial monitoring, the explosive growth of IoT has created exciting new business opportunities for real time calls and messaging. In his session at Internet of @ThingsExpo, Ivelin Ivanov, CEO and Co-Founder of Telestax, will share some of the new revenue sources that IoT created for Restcomm – the open source telephony platform from Telestax. Ivelin Ivanov is a technology entrepreneur who founded Mobicents, an Open Source VoIP Platform, to help create, deploy, and manage applications integrating voice, video and data. He is the co-founder of TeleStax, an Open Source Cloud Communications company that helps the shift from legacy IN/SS7 telco networks to IP-based cloud comms. An early investor in multiple start-ups, he still finds time to code for his companies and contribute to open source projects.
The Internet of Things (IoT) promises to create new business models as significant as those that were inspired by the Internet and the smartphone 20 and 10 years ago. What business, social and practical implications will this phenomenon bring? That's the subject of "Monetizing the Internet of Things: Perspectives from the Front Lines," an e-book released today and available free of charge from Aria Systems, the leading innovator in recurring revenue management.
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges.
There’s Big Data, then there’s really Big Data from the Internet of Things. IoT is evolving to include many data possibilities like new types of event, log and network data. The volumes are enormous, generating tens of billions of logs per day, which raise data challenges. Early IoT deployments are relying heavily on both the cloud and managed service providers to navigate these challenges. In her session at 6th Big Data Expo®, Hannah Smalltree, Director at Treasure Data, to discuss how IoT, Big Data and deployments are processing massive data volumes from wearables, utilities and other machines.
All major researchers estimate there will be tens of billions devices – computers, smartphones, tablets, and sensors – connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be!
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at Internet of @ThingsExpo, Erik Lagerway, Co-founder of Hookflash, will walk through the shifting landscape of traditional telephone and voice services to the modern P2P RTC era of OTT cloud assisted services.
While great strides have been made relative to the video aspects of remote collaboration, audio technology has basically stagnated. Typically all audio is mixed to a single monaural stream and emanates from a single point, such as a speakerphone or a speaker associated with a video monitor. This leads to confusion and lack of understanding among participants especially regarding who is actually speaking. Spatial teleconferencing introduces the concept of acoustic spatial separation between conference participants in three dimensional space. This has been shown to significantly improve comprehension and conference efficiency.
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, will discuss single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example to explain some of these concepts including when to use different storage models.
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridstore delivers vmOptimized™ Storage that self-optimizes to each application or VM across both virtual and physical environments. Leveraging a grid architecture, Gridstore delivers the first end-to-end storage QoS to ensure the most important App or VM performance is never compromised. The storage grid, that uses Gridstore’s performance optimized nodes or capacity optimized nodes, starts with as few a...
The Transparent Cloud-computing Consortium (abbreviation: T-Cloud Consortium) will conduct research activities into changes in the computing model as a result of collaboration between "device" and "cloud" and the creation of new value and markets through organic data processing High speed and high quality networks, and dramatic improvements in computer processing capabilities, have greatly changed the nature of applications and made the storing and processing of data on the network commonplace. These technological reforms have not only changed computers and smartphones, but are also changing the data processing model for all information devices. In particular, in the area known as M2M (Machine-To-Machine), there are great expectations that information with a new type of value can be produced using a variety of devices and sensors saving/sharing data via the network and through large-scale cloud-type data processing. This consortium believes that attaching a huge number of devic...
Innodisk is a service-driven provider of industrial embedded flash and DRAM storage products and technologies, with a focus on the enterprise, industrial, aerospace, and defense industries. Innodisk is dedicated to serving their customers and business partners. Quality is vitally important when it comes to industrial embedded flash and DRAM storage products. That’s why Innodisk manufactures all of their products in their own purpose-built memory production facility. In fact, they designed and built their production center to maximize manufacturing efficiency and guarantee the highest quality of our products.
Can call centers hang up the phones for good? Intuitive Solutions did. WebRTC enabled this contact center provider to eliminate antiquated telephony and desktop phone infrastructure with a pure web-based solution, allowing them to expand beyond brick-and-mortar confines to a home-based agent model. Download Slide Deck: ▸ Here
All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. Over the summer Gartner released its much anticipated annual Hype Cycle report and the big news is that Internet of Things has now replaced Big Data as the most hyped technology. Indeed, we're hearing more and more about this fascinating new technological paradigm. Every other IT news item seems to be about IoT and its implications on the future of digital business.
BSQUARE is a global leader of embedded software solutions. We enable smart connected systems at the device level and beyond that millions use every day and provide actionable data solutions for the growing Internet of Things (IoT) market. We empower our world-class customers with our products, services and solutions to achieve innovation and success. For more information, visit www.bsquare.com.
With the iCloud scandal seemingly in its past, Apple announced new iPhones, updates to iPad and MacBook as well as news on OSX Yosemite. Although consumers will have to wait to get their hands on some of that new stuff, what they can get is the latest release of iOS 8 that Apple made available for most in-market iPhones and iPads. Originally announced at WWDC (Apple’s annual developers conference) in June, iOS 8 seems to spearhead Apple’s newfound focus upon greater integration of their products into everyday tasks, cross-platform mobility and self-monitoring. Before you update your device, here is a look at some of the new features and things you may want to consider from a mobile security perspective.