Welcome!

Blog Feed Post

Correlating JavaScript Errors with Slow CDN Performance

JavaScript Errors can happen for many different reasons: special behavior of certain browsers that weren’t tested; a real coding mistake that slipped through the delivery pipeline; poorly handled timeouts, and I am sure the list goes on.

In this blog we discuss yet a different reason which was brought to my attention by Gerald Madlsperger, one of our long term Dynatrace AppMon super users: A CDN server issue resulting in non-delivered static resource files (CSS) leading to spikes in JavaScript errors.

Let’s review the steps that Gerald took to identify and analyze the issue, and learn which metrics he looked at on both the end-user and server sides. And, because not everyone is fortunate enough to have an expert like Gerald in their team, we show you how Dynatrace automates these steps through our Problem Pattern Detection and with Artificial Intelligence.

The Impact: JavaScript Exception Spikes

The problem that Gerald dealt with was visible in a daily spike of JavaScript errors for a particular web application. The spike always occurred at the same time – between 10:30 and 10:35 a.m.:

Charting the number of captured JavaScript errors captured through real user monitoring from Dynatrace AppMon

The impact was seen across every browser and every geo location. So it was not something that they simply missed in testing, nor was it a problem related with connection or timeout issues in a certain geo location.

The Problem: Object not found errors

To learn more about these errors Gerald compared the type of errors occurring prior to the spike and those that occurred during the spike. He wanted to see whether there was a certain pattern, or type of JavaScript error, that occurred more often within that time frame, hoping that this would take him one step closer to the root cause.

It turned out the JavaScript errors that occurred more frequently during these five minutes were all around HTML objects that couldn’t be found on the page by some of the JavaScript code:

Comparing JavaScript Errors that happen in two different time frames makes it easy to see which Errors are causing the spike.

Therefore, the problem was not necessarily bad JavaScript code, but most likely related to components that were missing or couldn’t be loaded on the page.

Root Cause: Slow CDNs caused by bad CRON job

Gerald’s next step was to drill down to some of these real end-user browser sessions. He wanted to see whether there was anything else abnormal about them. Turns out that most of these users had one thing in common: a very slow responding CDN Server:

User Action PurePaths show that content from their CDN servers was extremely slow in downloading.

As a final step Gerald created the following chart where he correlates the number of JavaScript Errors with the Download Time from that CDN Server. Now it was clear that very day from 10:30 – 10:35 a.m. there was a download time spike on the CDN Server that correlated with the spike in JavaScript errors:

Clear correlation between slow CDN download times to spikes in the number of JavaScript errors.

CRON Jobs to be blamed

After discussing this data with the systems engineers it turned out that two of their CDN Servers ran the same CRON job for log file rotation at the exact same time every day. This resulted in a brief outage of the CDN. That outage caused a delay or failed loading of static CSS files which resulted in the JavaScript code generating “object not found” errors.

Better rely on Dynatrace in case Gerald is not there for you!

First: Hats off to Gerald for doing a great job digging through the Dynatrace AppMon data. Also, thanks for sharing the dashboards which are useful when dealing with CDNs or 3rd parties.

While Dynatrace AppMon collects all this data to make troubleshooting of these problems easier, it requires you to know how to navigate the data. Because of scenarios shared by Gerald and others over the years, we have made significant investment in automating error, problem and root-cause detection.

In the latest versions of Dynatrace AppMon (sign up for your lifetime AppMon Personal License) we automate problem pattern detection, and highlight the “Top Findings” for both End-User and Server-Side Performance Hotspots in the Dynatrace AppMon Web Interface:

Dynatrace AppMon automatically shows you the top findings on why end user or server side performance is impacted

In the Dynatrace SaaS/Managed platform (sign up for our Dynatrace SaaS trial) we went a step further by running all this data through our Artificial Intelligence Engine. A problem like the one Gerald detected would pop up in a Problem Ticket, and include the information on the Impact and Root Cause. This allows you to analyze and fix these problems, even if you don’t have an expert like Gerald on your team. It just means that you can spend more time on innovating, rather than bug hunting.

Dynatrace Artificial Intelligence automatically shows you Impact and Root Cause of any type of End User, Server Side or Infrastructure Issue.

If you have stories like this one that you want to share with your peers, please let us know. Send me an email to Share your PurePath or your Best Artificially Detected Problem Pattern.

The post Correlating JavaScript Errors with Slow CDN Performance appeared first on Dynatrace blog – monitoring redefined.

Read the original blog entry...

More Stories By Dynatrace Blog

Building a revolutionary approach to software performance monitoring takes an extraordinary team. With decades of combined experience and an impressive history of disruptive innovation, that’s exactly what we ruxit has.

Get to know ruxit, and get to know the future of data analytics.

Latest Stories
In order to meet the rapidly changing demands of today’s customers, companies are continually forced to redefine their business strategies in order to meet these needs, stay relevant and continue to see profitable growth. IoT deployment and development is integral in this transformation, and today businesses are increasingly seeing the value of investing their resources into IoT deployments. These technologies are able increase ROI through projects such as connecting supply chains or enabling sm...
SYS-CON Events announced today that Outscale, a global pure play Infrastructure as a Service provider and strategic partner of Dassault Systèmes, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2010, Outscale simplifies infrastructure complexities and boosts the business agility of its customers. Outscale delivers a secure, reliable and industrial strength solution for its customers, which in...
Most DevOps journeys involve several phases of maturity. Research shows that the inflection point where organizations begin to see maximum value is when they implement tight integration deploying their code to their infrastructure. Success at this level is the last barrier to at-will deployment. Storage, for instance, is more capable than where we read and write data. In his session at @DevOpsSummit at 20th Cloud Expo, Josh Atwell, a Developer Advocate for NetApp, will discuss the role and value...
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Ge...
When NSA's digital armory was leaked, it was only a matter of time before the code was morphed into a ransom seeking worm. This talk, designed for C-level attendees, demonstrates a Live Hack of a virtual environment to show the ease in which any average user can leverage these tools and infiltrate their network environment. This session will include an overview of the Shadbrokers NSA leak situation.
As cloud adoption continues to transform business, today's global enterprises are challenged with managing a growing amount of information living outside of the data center. The rapid adoption of IoT and increasingly mobile workforce are exacerbating the problem. Ensuring secure data sharing and efficient backup poses capacity and bandwidth considerations as well as policy and regulatory compliance issues.
SYS-CON Events announced today that delaPlex will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. delaPlex pioneered Software Development as a Service (SDaaS), which provides scalable resources to build, test, and deploy software. It’s a fast and more reliable way to develop a new product or expand your in-house team.
In his opening keynote at 20th Cloud Expo, Michael Maximilien, Research Scientist, Architect, and Engineer at IBM, will motivate why realizing the full potential of the cloud and social data requires artificial intelligence. By mixing Cloud Foundry and the rich set of Watson services, IBM's Bluemix is the best cloud operating system for enterprises today, providing rapid development and deployment of applications that can take advantage of the rich catalog of Watson services to help drive insigh...
SYS-CON Events announced today that Interoute has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Interoute is the owner operator of Europe's largest network and a global cloud services platform, which encompasses over 70,000 km of lit fiber, 15 data centers, 17 virtual data centers and 33 colocation centers, with connections to 195 additional partner data centers. Our full-service Unifie...
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo Silicon Valley Call for Papers is now open.
Amazon started as an online bookseller 20 years ago. Since then, it has evolved into a technology juggernaut that has disrupted multiple markets and industries and touches many aspects of our lives. It is a relentless technology and business model innovator driving disruption throughout numerous ecosystems. Amazon’s AWS revenues alone are approaching $16B a year making it one of the largest IT companies in the world. With dominant offerings in Cloud, IoT, eCommerce, Big Data, AI, Digital Assis...
The 21st International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Machine Learning and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding busin...
Interested in leveling up on your Cloud Foundry skills? Join IBM for Cloud Foundry Days on June 7 at Cloud Expo New York at the Javits Center in New York City. Cloud Foundry Days is a free half day educational conference and networking event. Come find out why Cloud Foundry is the industry's fastest-growing and most adopted cloud application platform.
For financial firms, the cloud is going to increasingly become a crucial part of dealing with customers over the next five years and beyond, particularly with the growing use and acceptance of virtual currencies. There are new data storage paradigms on the horizon that will deliver secure solutions for storing and moving sensitive financial data around the world without touching terrestrial networks. In his session at 20th Cloud Expo, Cliff Beek, President of Cloud Constellation Corporation, w...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In his Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, will explore t...