Welcome!

IoT User Interface Authors: Elizabeth White, Peter Silva, Yakov Fain, John Basso, Derek Weeks

Related Topics: IoT User Interface, Java IoT, Industrial IoT, Microservices Expo, Microsoft Cloud, @CloudExpo

IoT User Interface: Article

Diagnosing Stuck Transactions in Minutes

A Step-by-Step Guide

Does the following situation sound familiar? From one minute to the other, your production servers grind to a halt, terse emails are complemented by equally hectic phone calls, and the first order of business is to get back up and running. After the dust settles, you're usually left with a pile of log files and the assignment of figuring out what happened, why it happened, and what to do to keep it from happening again.

A common first step is trying to reproduce what has gone wrong. More often than not, this consumes a considerable amount of time that would be better spent on actually fixing the problem. In this first blog post of a series, I will present a Step-by-Step Guide to Diagnose Stuck Transactions within minutes and show how a modern APM Solution helps to pinpoint common production problems, without spending hours on reproducing it at first.

The Problem: Response Time Increases
One of our customers deployed a new version of their prime web application and, for the first couple of days, everything seemed fine. One evening, their operations team was alerted about significantly increasing response time, and upon further investigation they recognized that a Stuck Transaction was blocking their application. While restarting the server solved the problem from an operations perspective it is not a long term solution as currently processing transactions get canceled and users are thrown off the system.

Their APM solution automatically captures thread dumps in case of too long running or stuck transactions. These dumps assist developers with diagnosing the issue. Let's take this example and walk through one of the problems often seen in a production environment: Diagnosing Stuck Transactions and Identifying the Root Cause.

Step 1: Identify problematic JVM/CLR
To identify the correct thread dump to analyze, it's important to know which server was affected by the stuck transaction and at what time that happened.

The transaction flow indicates a problem on one of the application servers

When drilling to the actual transactions that flow through that application server and focusing on the timeframe just before the server got restarted, I noticed a timed-out PurePath that spent 100% in sync time. This means that all it did was wait for one or more monitors, which makes it a likely culprit for our stuck transaction.

The PurePath reveals the information about which Application Server (=Agent) was involved in that stuck transaction

Step 2: Identify blocked threads
Having identified the affected application server, we can browse the list of available thread dumps and open the corresponding one.

Thread dump overview on runnable, blocked, waiting and timed waiting threads

When looking at the thread dump, threads can be grouped by their state to get a quick overview on how many threads the application executed when the dump was performed and how many of them were actually blocked. In this case, we are looking at four threads as Figure 4 shows.

Out of the 600+ Threads in the application, 4 are blocked and subject for further investigation

Step 3: Identify root cause
Already the first one of these threads is the thread from our timed-out PurePath we looked at in Step 1 - identifiable by its ID. We also get the most important piece of information we need to identify the root cause: Which object is this thread waiting on, and who owns it?

We now know which method is blocking and that it is blocked because it waits for an object owned by another thread -> a potential deadlock?

Usually, the thread owning the object we are waiting for is highlighted in red. Given the number of threads in this dump, it's unlikely to spot it this way, but search for the ID of the owning thread giving us the following information:

The HistoryLayout thread owns a monitor object with two waiting threads, which causes the web request handler to block and run into a timeout for the end user - the deadlock is identified!

In this case, the method com.vaadin.ui.Table.unregisterPropertiesAndComponents is working on the same instance of ConfigurableReportsApplication that AbstractApplicationPortlet.handleRequest is waiting for. Having identified the thread, we have the full stack trace at hand in the lower pane, and can track down how this situation occurred.

Conclusion
Trying to reproduce such concurrency-related problems on a developer machine with typically requires a major effort. If your APM tool fully supports collaboration between teams, all analysis steps described above can be performed in your local environment, without direct access to production servers. Using an APM Solution like dynaTrace, it only took a couple of minutes to answer the crucial questions named above: we know exactly what happened and how it happened, and are thus also able to modify our application in a way to avoid this situation in the future.

More Stories By Wolfgang Gottesheim

Wolfgang Gottesheim has several years of experience as a software engineer and research assistant in the Java enterprise space. Currently he contributes to the strategic development of the dynaTrace enterprise solution as a Technology Strategy in the Compuware APM division’s Center of Excellence. He focuses on monitoring and optimizing applications in production.

Comments (0)

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.


@CloudExpo Stories
SYS-CON Events announced today that Isomorphic Software will exhibit at DevOps Summit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Isomorphic Software provides the SmartClient HTML5/AJAX platform, the most advanced technology for building rich, cutting-edge enterprise web applications for desktop and mobile. SmartClient combines the productivity and performance of traditional desktop software with the simp...
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
Extreme Computing is the ability to leverage highly performant infrastructure and software to accelerate Big Data, machine learning, HPC, and Enterprise applications. High IOPS Storage, low-latency networks, in-memory databases, GPUs and other parallel accelerators are being used to achieve faster results and help businesses make better decisions. In his session at 18th Cloud Expo, Michael O'Neill, Strategic Business Development at NVIDIA, focused on some of the unique ways extreme computing is...
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
With over 720 million Internet users and 40–50% CAGR, the Chinese Cloud Computing market has been booming. When talking about cloud computing, what are the Chinese users of cloud thinking about? What is the most powerful force that can push them to make the buying decision? How to tap into them? In his session at 18th Cloud Expo, Yu Hao, CEO and co-founder of SpeedyCloud, answered these questions and discussed the results of SpeedyCloud’s survey.
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
Actian Corporation has announced the latest version of the Actian Vector in Hadoop (VectorH) database, generally available at the end of July. VectorH is based on the same query engine that powers Actian Vector, which recently doubled the TPC-H benchmark record for non-clustered systems at the 3000GB scale factor (see tpc.org/3323). The ability to easily ingest information from different data sources and rapidly develop queries to make better business decisions is becoming increasingly importan...
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices 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 business opportuni...
Qosmos has announced new milestones in the detection of encrypted traffic and in protocol signature coverage. Qosmos latest software can accurately classify traffic encrypted with SSL/TLS (e.g., Google, Facebook, WhatsApp), P2P traffic (e.g., BitTorrent, MuTorrent, Vuze), and Skype, while preserving the privacy of communication content. These new classification techniques mean that traffic optimization, policy enforcement, and user experience are largely unaffected by encryption. In respect wit...
Deploying applications in hybrid cloud environments is hard work. Your team spends most of the time maintaining your infrastructure, configuring dev/test and production environments, and deploying applications across environments – which can be both time consuming and error prone. But what if you could automate provisioning and deployment to deliver error free environments faster? What could you do with your free time?
SYS-CON Events announced today that Hitrons Solutions will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Hitrons Solutions Inc. is distributor in the North American market for unique products and services of small and medium-size businesses, including cloud services and solutions, SEO marketing platforms, and mobile applications.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
SYS-CON Events announced today that eCube Systems, a leading provider of middleware modernization, integration, and management solutions, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. eCube Systems offers a family of middleware evolution products and services that maximize return on technology investment by leveraging existing technical equity to meet evolving business needs. ...
DevOps at Cloud Expo – being held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's largest enterprises – and delivering real results. Am...
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long dev...
SYS-CON Events announced today that StarNet Communications will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. StarNet Communications’ FastX is the industry first cloud-based remote X Windows emulator. Using standard Web browsers (FireFox, Chrome, Safari, etc.) users from around the world gain highly secure access to applications and data hosted on Linux-based servers in a central data center. ...
Traditional on-premises data centers have long been the domain of modern data platforms like Apache Hadoop, meaning companies who build their business on public cloud were challenged to run Big Data processing and analytics at scale. But recent advancements in Hadoop performance, security, and most importantly cloud-native integrations, are giving organizations the ability to truly gain value from all their data. In his session at 19th Cloud Expo, David Tishgart, Director of Product Marketing ...