|By Andreas Grabner||
|April 14, 2014 11:00 AM EDT||
Have you seen this error message before "java.sql.Exception: ORA-00060: deadlock detected while waiting for resource"?
This is caused when parallel updates require locks on either rows or tables in your database. I recently ran into this exception on an instance of an IBM eCommerce Server. The first thought was that there are simply too many people hitting the same functionality that updates Sales Tax Summary information - which was showing up in the call stack of the exception:
Exception stack trace showing that createOrderTaxes ran into the deadlock issue on the database
The logical conclusion would be to blame this on too many folks accessing this functionality or outdated table statistics causing update statements to run too long causing others to run into that lock. It turned out to be caused by something that wasn't that obvious and wouldn't have shown up in any Exception stack traces or log files. A misconfigured timeout setting on the load balancer caused a re-execute of the original incoming web request. While the first app server was still updating the table and holding the lock - as it had a longer timeout specified as the load balancer - the second app server tried to do the same thing causing that exception.
In this article I'll show you the steps necessary to analyze the symptoms (timeouts and client errors) and to identify and fix the root cause of the problem.
Step #1: Identifying Who and What Is Impacted
Identifying failing results is easy - start by looking at HTTP Response Codes (Web Server Access Log), Severe Log Messages (App Server Logs) or problematic Exception objects (either in log files or other monitoring tools). In our case I identified the SQL Lock Exception, a corresponding severe log message and the resulting HTTP 500 and also traced it back to the individual users and their actions that caused these issues.
Linking the errors to the User Action reveals that the problem happens when adding items to the shopping cart
This impacts our business.
Now we know that this problem impacts a critical feature in our app: Users can't add items to their cart.
Step #2: Understanding the Transaction Flow
Before drilling deeper I typically get an overview of the flow of the transaction from the browser all the way back to the database. This high-level view lets me understand which application components are involved and how they are interconnected. The transaction flow in this case highlights some interesting issues with the "Add Item to Cart" click. It appears to execute more than 33k SQL Statements for this single user interaction, causing 45% time executed just in Oracle:
Transaction Flow highlights several hotspots such as 33k SQL Executions in Total and Load Balancer (IHS) splitting up a request
This Is an Architectural Problem
Getting the full end-to-end execution path for a single user interaction (Add Item to Cart) and seeing how it "branches" out makes it really obvious how these individual problems (too many SQL, High Execution Time, ...) end up impacting end users. Just spotting the individual hotspots without having this connection would make it harder to understand the real root cause.
For steps 3 & 4, and for a list of key takeaways, click here for the full article
Choosing the right cloud for your workloads is a balancing act that can cost your organization time, money and aggravation - unless you get it right the first time. Economics, speed, performance, accessibility, administrative needs and security all play a vital role in dictating your approach to the cloud. Without knowing the right questions to ask, you could wind up paying for capacity you'll never need or underestimating the resources required to run your applications.
Jan. 20, 2017 04:00 AM EST Reads: 3,923
WebRTC is about the data channel as much as about video and audio conferencing. However, basically all commercial WebRTC applications have been built with a focus on audio and video. The handling of “data” has been limited to text chat and file download – all other data sharing seems to end with screensharing. What is holding back a more intensive use of peer-to-peer data? In her session at @ThingsExpo, Dr Silvia Pfeiffer, WebRTC Applications Team Lead at National ICT Australia, looked at differ...
Jan. 20, 2017 02:30 AM EST Reads: 5,015
Adding public cloud resources to an existing application can be a daunting process. The tools that you currently use to manage the software and hardware outside the cloud aren’t always the best tools to efficiently grow into the cloud. All of the major configuration management tools have cloud orchestration plugins that can be leveraged, but there are also cloud-native tools that can dramatically improve the efficiency of managing your application lifecycle. In his session at 18th Cloud Expo, ...
Jan. 20, 2017 02:15 AM EST Reads: 6,043
Security, data privacy, reliability and regulatory compliance are critical factors when evaluating whether to move business applications from in-house client hosted environments to a cloud platform. In her session at 18th Cloud Expo, Vandana Viswanathan, Associate Director at Cognizant, In this session, will provide an orientation to the five stages required to implement a cloud hosted solution validation strategy.
Jan. 20, 2017 02:00 AM EST Reads: 3,632
The security needs of IoT environments require a strong, proven approach to maintain security, trust and privacy in their ecosystem. Assurance and protection of device identity, secure data encryption and authentication are the key security challenges organizations are trying to address when integrating IoT devices. This holds true for IoT applications in a wide range of industries, for example, healthcare, consumer devices, and manufacturing. In his session at @ThingsExpo, Lancen LaChance, vic...
Jan. 20, 2017 02:00 AM EST Reads: 6,571
With the proliferation of both SQL and NoSQL databases, organizations can now target specific fit-for-purpose database tools for their different application needs regarding scalability, ease of use, ACID support, etc. Platform as a Service offerings make this even easier now, enabling developers to roll out their own database infrastructure in minutes with minimal management overhead. However, this same amount of flexibility also comes with the challenges of picking the right tool, on the right ...
Jan. 20, 2017 02:00 AM EST Reads: 5,323
With all the incredible momentum behind the Internet of Things (IoT) industry, it is easy to forget that not a single CEO wakes up and wonders if “my IoT is broken.” What they wonder is if they are making the right decisions to do all they can to increase revenue, decrease costs, and improve customer experience – effectively the same challenges they have always had in growing their business. The exciting thing about the IoT industry is now these decisions can be better, faster, and smarter. Now ...
Jan. 20, 2017 01:45 AM EST Reads: 4,264
Security, data privacy, reliability, and regulatory compliance are critical factors when evaluating whether to move business applications from in-house, client-hosted environments to a cloud platform. Quality assurance plays a vital role in ensuring that the appropriate level of risk assessment, verification, and validation takes place to ensure business continuity during the migration to a new cloud platform.
Jan. 20, 2017 01:15 AM EST Reads: 1,352
"Splunk basically takes machine data and we make it usable, valuable and accessible for everyone. The way that plays in DevOps is - we need to make data-driven decisions to delivering applications," explained Andi Mann, Chief Technology Advocate at Splunk and @DevOpsSummit Conference Chair, in this SYS-CON.tv interview at @DevOpsSummit at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Jan. 20, 2017 01:15 AM EST Reads: 2,141
Who are you? How do you introduce yourself? Do you use a name, or do you greet a friend by the last four digits of his social security number? Assuming you don’t, why are we content to associate our identity with 10 random digits assigned by our phone company? Identity is an issue that affects everyone, but as individuals we don’t spend a lot of time thinking about it. In his session at @ThingsExpo, Ben Klang, Founder & President of Mojo Lingo, discussed the impact of technology on identity. Sho...
Jan. 20, 2017 12:45 AM EST Reads: 4,114
A critical component of any IoT project is what to do with all the data being generated. This data needs to be captured, processed, structured, and stored in a way to facilitate different kinds of queries. Traditional data warehouse and analytical systems are mature technologies that can be used to handle certain kinds of queries, but they are not always well suited to many problems, particularly when there is a need for real-time insights.
Jan. 20, 2017 12:00 AM EST Reads: 6,337
In his session at DevOps Summit, Tapabrata Pal, Director of Enterprise Architecture at Capital One, will tell a story about how Capital One has embraced Agile and DevOps Security practices across the Enterprise – driven by Enterprise Architecture; bringing in Development, Operations and Information Security organizations together. Capital Ones DevOpsSec practice is based upon three "pillars" – Shift-Left, Automate Everything, Dashboard Everything. Within about three years, from 100% waterfall, C...
Jan. 19, 2017 11:45 PM EST Reads: 9,925
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Jan. 19, 2017 09:45 PM EST Reads: 7,705
"We provide DevOps solutions. We also partner with some key players in the DevOps space and we use the technology that we partner with to engineer custom solutions for different organizations," stated Himanshu Chhetri, CTO of Addteq, in this SYS-CON.tv interview at DevOps at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jan. 19, 2017 09:00 PM EST Reads: 4,583
DevOps tends to focus on the relationship between Dev and Ops, putting an emphasis on the ops and application infrastructure. But that’s changing with microservices architectures. In her session at DevOps Summit, Lori MacVittie, Evangelist for F5 Networks, will focus on how microservices are changing the underlying architectures needed to scale, secure and deliver applications based on highly distributed (micro) services and why that means an expansion into “the network” for DevOps.
Jan. 19, 2017 08:45 PM EST Reads: 5,417
WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, discussed the importance of WebRTC and how it enables companies to focus o...
Jan. 19, 2017 07:30 PM EST Reads: 4,241
Web Real-Time Communication APIs have quickly revolutionized what browsers are capable of. In addition to video and audio streams, we can now bi-directionally send arbitrary data over WebRTC's PeerConnection Data Channels. With the advent of Progressive Web Apps and new hardware APIs such as WebBluetooh and WebUSB, we can finally enable users to stitch together the Internet of Things directly from their browsers while communicating privately and securely in a decentralized way.
Jan. 19, 2017 05:15 PM EST Reads: 3,123
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
Jan. 19, 2017 04:45 PM EST Reads: 3,776
@DevOpsSummit at Cloud taking place June 6-8, 2017, at Javits Center, New York City, is co-located with the 20th International 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 developm...
Jan. 19, 2017 04:45 PM EST Reads: 3,503
"We're bringing out a new application monitoring system to the DevOps space. It manages large enterprise applications that are distributed throughout a node in many enterprises and we manage them as one collective," explained Kevin Barnes, President of eCube Systems, in this SYS-CON.tv interview at DevOps at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jan. 19, 2017 04:15 PM EST Reads: 5,427