SYS-CON MEDIA Authors: Jason Bloomberg, Elizabeth White, Zakia Bouachraoui, Andy Thurai, Liz McMillan

Blog Feed Post

Some thoughts on database locking in Oracle and Microsoft SQL Server


Deadlocks are the bane of those of us responsible for designing and maintaining any type of database system. I’ve written about these before on the dispatcher level. However this time around, I’d like to discuss them a little further “down” so to speak, at the database level. Also in talking to various people about this topic I've found that it’s potentially the most divisive question since “Tastes good vs. Less filling

Database deadlocks are much like application ones, typically come when two processes are trying to access the same database row at the same time. Most often this is when the system is trying to read and write to the row at the same time. A nice explanation can be found here. What we essentially wind up with is the database equivalent of a traffic jam where no one can move. It’s interesting to note that both Microsoft and SQL server handle these locking scenarios differently. I’m not going to go into DB2 at the moment but will address it if there is sufficient demand.

When dealing with SQL Server, management of locks is handled through the use of the “Hint” called No Lock. According to MSDN:

Hints are options or strategies specified for enforcement by the SQL Server query processor on SELECT, INSERT, UPDATE, or DELETE statements. The hints override any execution plan the query optimizer might select for a query. (Source)
When NOLOCK is used this is the same as using READUNCOMMITTED which some of you might have be familiar with if you did the NetWeaver portion of the IDM install when setting up the data source. Using this option keeps the SQL Server database engine from issuing locks. The big issue here is that one runs the risk of having dirty (old) data in the database operations. Be careful when using NOLOCK for this reason. Even though the SAP Provisioning Framework makes extensive use of the NOLOCK functionality, they regression test the heck out of the configuration. Make sure you do, too misuse of NOLOCK can lead to bad things happening in the Identity Store database.

There is also a piece of SQL Server functionality referred to as Snapshot Isolation which appears to work as a NOLOCK writ large where database snapshots are held in the TEMPDB for processing (source) This functionality was recommended by a DBA I worked with on a project some time ago. The functionality was tested in DEV and then rolled to the customer’s PRODUCTION instance.

Oracle is a little different in the way that it approaches locking in that the system has more internal management of conflicts through use of rollback logs forcing data to be committed before writes can occur and thus deadlocks occur much less often (Source) This means that there is no similar NOLOCK functionality in the Oracle Database System.

One final thing to consider with database deadlocks is how the database is being accessed, regardless of the database being used.  It is considered a best practice in SAP IDM to use To Identity Store passes as opposed to uIS_SetValue whenever possible (Source)

At the end of the day, I don’t know that I can really tell you to employ these mechanisms or not. In general we do know that it’s better not to have deadlocks than to have them and to do what you can to achieve this goal. In general, if you are going to use these techniques, do make sure you are doing so in concert with your DBA team and after careful testing. I have seen Microsoft SQL Server’s Snapshot Isolation work well in a busy productive environment, but I will not recommend its universal adoption as I can’t tell you how well it will work in yourenvironment. I will however recommend that you look into it with your DBA team if you are experiencing Deadlocks in SQL Server.


Read the original blog entry...

More Stories By Matthew Pollicove

Matt Pollicove is an Identity Management architect, engineer, trainer, project manager, author and blogger with experience in user account provisioning, data synchronization, virtual directory and password management solutions. As a MaXware Technical Consultant and later as a System Engineer, he worked extensively with MaXware (now SAP) software products in large customer environments. In the past Matt has worked with several leading national and international consulting firms and is currently a Sr. Principal Consultant for Commercium Technologies. He is currently the Practice Lead for SAP NetWeaver Identity Management and SailPoint IIQ.

Latest Stories
The Software Defined Data Center (SDDC), which enables organizations to seamlessly run in a hybrid cloud model (public + private cloud), is here to stay. IDC estimates that the software-defined networking market will be valued at $3.7 billion by 2016. Security is a key component and benefit of the SDDC, and offers an opportunity to build security 'from the ground up' and weave it into the environment from day one. In his session at 16th Cloud Expo, Reuven Harrison, CTO and Co-Founder of Tufin, ...
While the focus and objectives of IoT initiatives are many and diverse, they all share a few common attributes, and one of those is the network. Commonly, that network includes the Internet, over which there isn't any real control for performance and availability. Or is there? The current state of the art for Big Data analytics, as applied to network telemetry, offers new opportunities for improving and assuring operational integrity. In his session at @ThingsExpo, Jim Frey, Vice President of S...
"We were founded in 2003 and the way we were founded was about good backup and good disaster recovery for our clients, and for the last 20 years we've been pretty consistent with that," noted Marc Malafronte, Territory Manager at StorageCraft, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Historically, some banking activities such as trading have been relying heavily on analytics and cutting edge algorithmic tools. The coming of age of powerful data analytics solutions combined with the development of intelligent algorithms have created new opportunities for financial institutions. In his session at 20th Cloud Expo, Sebastien Meunier, Head of Digital for North America at Chappuis Halder & Co., discussed how these tools can be leveraged to develop a lasting competitive advantage ...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settl...
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 their Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, and Mark Lav...
@CloudEXPO and @ExpoDX, two of the most influential technology events in the world, have hosted hundreds of sponsors and exhibitors since our launch 10 years ago. @CloudEXPO and @ExpoDX New York and Silicon Valley provide a full year of face-to-face marketing opportunities for your company. Each sponsorship and exhibit package comes with pre and post-show marketing programs. By sponsoring and exhibiting in New York and Silicon Valley, you reach a full complement of decision makers and buyers in ...
According to the IDC InfoBrief, Sponsored by Nutanix, “Surviving and Thriving in a Multi-cloud World,” multicloud deployments are now the norm for enterprise organizations – less than 30% of customers report using single cloud environments. Most customers leverage different cloud platforms across multiple service providers. The interoperability of data and applications between these varied cloud environments is growing in importance and yet access to hybrid cloud capabilities where a single appl...
"At the keynote this morning we spoke about the value proposition of Nutanix, of having a DevOps culture and a mindset, and the business outcomes of achieving agility and scale, which everybody here is trying to accomplish," noted Mark Lavi, DevOps Solution Architect at Nutanix, in this SYS-CON.tv interview at @DevOpsSummit at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
In today's always-on world, customer expectations have changed. Competitive differentiation is delivered through rapid software innovations, the ability to respond to issues quickly and by releasing high-quality code with minimal interruptions. DevOps isn't some far off goal; it's methodologies and practices are a response to this demand. The demand to go faster. The demand for more uptime. The demand to innovate. In this keynote, we will cover the Nutanix Developer Stack. Built from the foundat...
"NetApp's vision is how we help organizations manage data - delivering the right data in the right place, in the right time, to the people who need it, and doing it agnostic to what the platform is," explained Josh Atwell, Developer Advocate for NetApp, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Sold by Nutanix, Nutanix Mine with Veeam can be deployed in minutes and simplifies the full lifecycle of data backup operations, including on-going management, scaling and troubleshooting. The offering combines highly-efficient storage working in concert with Veeam Backup and Replication, helping customers achieve comprehensive data protection for all their workloads — virtual, physical and private cloud —to meet increasing business demands for uptime and productivity.
"Cloud computing is certainly changing how people consume storage, how they use it, and what they use it for. It's also making people rethink how they architect their environment," stated Brad Winett, Senior Technologist for DDN Storage, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
A look across the tech landscape at the disruptive technologies that are increasing in prominence and speculate as to which will be most impactful for communications – namely, AI and Cloud Computing. In his session at 20th Cloud Expo, Curtis Peterson, VP of Operations at RingCentral, highlighted the current challenges of these transformative technologies and shared strategies for preparing your organization for these changes. This “view from the top” outlined the latest trends and developments i...
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...