Blogs

June 2022 President's Letter

By Iqbal Goralwalla posted 17 days ago
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Hello again to our IDUG members all over the world! I encourage each of you to click here and view details on all of the IDUG 2022 North America Db2 Tech Conference education sessions—and then register for NA22 and reserve your lodging at our special $199/night rate. In addition to this video by IDUG , here are some special greetings from your IDUG NACPC Presentations Team Lead Chris Muncan. IDUG is honored to strengthen everyone in this community by providing the highest quality education and services for Db2. We appreciate your support! Until next time—wherever you may be reading this—stay healthy and stay safe. Chris and I and your ...
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Cool factor of z16

By Emil Kotrc posted 25 days ago
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Cool Factor of IBM z16 Recently, I have been visiting a technical university with a short speech at a seminar and my topic was IBM mainframes. Fortunately, this was after IBM's announcement of the new machine IBM z16, so I had some great content to cover. One of the discussion point of course was the new processor - IBM Telum, and because the audience was geeky enough, a question was how does this chip compare with other processors, especially with Apple M1 Ultra released a bit sooner. Apparently, this is not a surprising question, I have heard this one even on IBM's session by Christian Jacobi (you can also listen to this podcast or terminal talk ...
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Db2 catalog tables - Statistics

By Denis Tronin posted May 24, 2022
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Db2 catalog tables – Statistics Written By: IBM Data Management Console Development Group Jun Liu , Guo Bin Zhao, Yinmei Chen Db2 maintains a set of catalog tables that describes the metadata of each database, including tables, indexes, views, schemas, procedures, sequences, etc. Authorized users can query those catalog tables to get useful information like how many tables are stored in the database, how many columns are defined for each table and what’s the column types, etc. But most of catalog tables are used by Db2 itself. A good example is the statistics associated with those database objects. Statistics in Db2 database is a very important kind of ...
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Exploring the Db2 for z/OS Catalog

By Emil Kotrc posted May 16, 2022
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Exploring the Db2 for z/OS Catalog Written by Sowmya Kameswaran Navigating and exploring the Db2 catalog is a very common activity for anyone who interacts with the database engine. Database administrators and application developers browse the object catalog for a multitude of reasons. Whether they want to view all objects, check the status of an object, locate statistics, browse the data, generate DDL, or any other action that involves working with catalog objects, having an intuitive and easy-to-use interface is a key component of working productively and efficiently. Most Db2 users are familiar with the object-type-based navigation provided ...
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May 2022 President's Letter

By Iqbal Goralwalla posted May 09, 2022
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Hello again to our IDUG members all over the world! I wanted to encourage every one of you to consider registering right now for the 2022 IDUG NA Db2 Tech Conference in Boston, USA, on July 11-14! A full Daily Schedule Grid is now available on our website, joining the full list of our technical breakout sessions’ presentations & presenters . And more agenda information is coming soon! As you know, our NA conference will be IDUG’s first hybrid event where you can participate on-site (to experience the full conference) or online (for access to select sessions). Today I wanted to note a few exciting pricing options for our members who will be ...
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Catalog Queries for Db2 for z/OS

By Emil Kotrc posted May 05, 2022
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Catalog Queries for Db2 for z/OS Introduction If you are experienced with database management systems outside of mainframe, you've probably heard about an information schema . This is a set of views that provide information about all tables, columns, and all other database objects defined in the system. Db2 for z/OS does not have an information schema, but has a Db2 catalog containing all the metadata about the objects. There is already a lot of blogs, articles, presentations about the Db2 catalog (for instance you can start with Denis' blog , which is an overview of the catalog, but also contains useful links - check it out); so why to ...
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Db2 for z/OS Dual Logging: zHyperWrite and zHyperLink—are they related?

By Emil Kotrc posted Apr 13, 2022
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Db2 for z/OS Dual Logging: zHyperWrite and zHyperLink—are they related? Sharon Roeder, IBM zHyperWrite and zHyperLink certainly sound very similar. Both have definite performance benefits for Db2 dual logging, and both require DFSMS Media Manager software to leverage specific z/OS features. However, when it comes to Db2 Log Manager, they are really two different sets of functionality controlled by two different system parameters. This discussion focuses on Db2 dual active logging. zHyperWrite In Db2 10 for z/OS, zHyperWrite support was added to improve overall Db2 performance for customer shops that use Peer-to-Peer Remote Copy (PPRC) where log ...
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April 2022 President's Letter

By Iqbal Goralwalla posted Apr 05, 2022
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Hello again to our IDUG members all over the world! At the moment (although I’m almost hesitant to even say it), it finally does feel like our world may be expanding a bit, after contracting so much as it has over what has now been more than two years of this global pandemic. Here’s an exciting snapshot of IDUG so far in 2022: Two weekends ago, the IDUG Board of Directors held what was only its second face-to-face board meeting in the last two years Last weekend, the EMEA Conference Planning Committee held its second face-to-face meeting since 2019 This weekend, the NA Conference Planning Committee will hold its first face-to-face meeting since 2019 ...
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Back to Basics: Algorithms for Recovery and Isolation Exploiting Semantics

By Emil Kotrc posted Apr 05, 2022
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Back to Basics: Algorithms for Recovery and Isolation Exploiting Semantics Most likely, you understand how logging in Db2 for z/OS works in general. There are log buffers, active logs, which get offloaded to archive logs, and all is being tracked in the bootstrap dataset. For more details about the basics refer to Martin Hubel's IDUG article . All conceptually pretty clear. However, have you ever heard about ARIES (Algorithms for Recovery and Isolation Exploiting Semantics)? The link before points to wikipedia where you can find more information, most importantly you can find there a link to a paper written by IBM Fellow, Dr. C. Mohan. Dr. Mohan's ...
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Travel through time with Db2 SQL to investigate complex application data change questions

By Brian Laube posted Mar 15, 2022
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Travel through time with Db2 SQL to investigate complex application data change questions The poor beleaguered support staff sometimes come up with the strangest questions. Why does policy 123 in the POLICY table have status code X. I could have sworn the status code should be Y. How could this be? Who did it? When? Why? That is actually a very interesting question and the application DBA might be able to help. In our case, the POLICY table has helpful field called “update_timestamp”. But the value for this row is from 10 years ago. Apparently, the application code must maintain this field and we should not always trust ...
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March 2022 President's Letter

By Iqbal Goralwalla posted Mar 08, 2022
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Hello again to our IDUG members all over the world. I know that everyone in the Db2 User community is really excited about 2022. In addition to our plans to return to face-to-face IDUG events this year, this will be a very big year for Db2! Of course, we hope to see you in person at our Db2 Tech Conferences in Boston and Edinburgh. But if you participated virtually in the 2021 IDUG EMEA conference last December, you already know what will make 2022 so special. IBM will be announcing a new release of Db2 for z/OS this year! It has been five years since the announcement of Db2 12. And with the announcement of continuous delivery and regular new Db2 functions ...
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Access Paths Part 1: The introduction of Db2 optimizer and cost model

By Tony Andrews posted Feb 21, 2022
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Access Paths Part 1: The introduction of Db2 optimizer and cost model: Posted By: Tony Andrews Written By: IBM Data Management Console Development Group Jun Liu, Yan Zeng, Jun Qing Huang, Bian Li Whether they are beginners or experienced DBA, they have more or less doubts about the behavior of Db2, especially in terms of the execution performance of SQL statements. The questions they often ask are: Obviously this SQL is very simple and only needs to return very few records, why did Db2 take so long? Why is there a primary key index on this table, but Db2 doesn't seem to use it at all? Why is this SQL sometimes fast and sometimes unbearably slow, and ...
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Implicit / Explicit objects – why SET CURRENT RULES makes a difference

By Javier Estrada Benavides posted Feb 09, 2022
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Written by Steen Rasmussen Client Services Consultant Broadcom Inc Implicit / Explicit objects – why SET CURRENT RULES makes a difference All of us have an opinion about IMPLICITLY created objects in a Db2 subsystem – it’s like a love/hate relationship. The ability for Db2 to automatically create the “needed” objects has been around for a while and this capability definitely has some pro’s and con’s depending on the specific organization and requirements. Most Db2 sites have a naming convention in place for various reasons. For example, a table name must start with “T”, a tablespace name must start with “S”, the second ...
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January 2022 President's Letter

By Iqbal Goralwalla posted Jan 12, 2022
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A very Happy New Year to all of you. I hope everyone had a good break and managed to spend some quality time with family and friends. We started 2021 with high expectations of a relatively better year in terms of Covid-19 restrictions. And it was, as vaccinations ramped up, albeit in the second half of the year. However, not enough to bring life back to complete normality. Like everyone else, IDUG had to make the difficult decision to convert the planned face-to-face IDUG EMEA conference in Edinburgh to a virtual one. The risks for an onsite conference were just too high. And once again, our volunteers adapted and stepped up, and together with the support ...
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This is not a pipe, it’s a pipeline: becoming a DevOps DBA – part 2

By Javier Estrada Benavides posted Dec 24, 2021
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This is not a pipe, it’s a pipeline: becoming a DevOps DBA – part 2 Written by: Marcus Davage CEng CITP MBCS Lead Product Developer Intelligent Z Optimization and Transformation BMC Software Last time, I quoted Belgian surrealist artist René Magritte, his ‘This is not a pipe’ painting and his comment that ‘Perception always intercedes between reality and ourselves.’ To bring yourself up to speed, you can read part 1 here The point I was making was that, when it comes to DevOps and databases, DBAs need to be involved from the outset of project design. Developers (including development DBAs) and operations ...
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This is not a pipe, it’s a pipeline: becoming a DevOps DBA – part 1

By Javier Estrada Benavides posted Dec 05, 2021
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This is not a pipe, it’s a pipeline: becoming a DevOps DBA – part 1 Written by: Marcus Davage CEng CITP MBCS Lead Product Developer Intelligent Z Optimization and Transformation BMC Software In 1929, Belgian surrealist artist René Magritte painted ‘The Treachery of Images’ aka ‘This is not a pipe’. He said, ‘Perception always intercedes between reality and ourselves.’ Pipes were ubiquitous then, as smartphones are today. Let’s consider a smartphone. It is far, far more than a phone. It is an all-in-one communications, entertainment and retail centre; this is not a phone. It satisfies modern demands ...
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November News: Upcoming Events & Conference Announcements

By Iqbal Goralwalla posted Nov 02, 2021
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With an uptake of more and more people being vaccinated against Covid-19, countries have opened their borders for travel over the past few months. This has opened the doors for IDUG committees to conduct their meetings face to face after almost two years. Face to face interaction is important for all of us at our workplace and more so for IDUG volunteers who give up some of their out of work time to help IDUG conduct it’s many activities. It helps rejuvenate what we believe in and keeps us motivated. A big thank you to all our volunteers for adapting to an online world over the past couple of years and continuing to help and support IDUG. This month, the first ...
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zPARMs or DSN Profiles?

By Javier Estrada Benavides posted Oct 27, 2021
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Javier Estrada Benavides javier.strad@gmail.com Setting your Db2 zParms to the right values can be a never ending task, but luckily the previous article from Emil Kotrc ( found in here ), gave a structure on what you’ll find, and several pointers so you can study some recommendations from other Db2 users and see how that fits to your site. The other side of the picture, as it is also mentioned there, is that we live in a big world of “it depends” situations. zParms will take an effect over the entire Db2 subsystem and its applications, therefore it means that in most cases you’ll need to take the following steps: Study your environment over time. ...
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About zParms

By Emil Kotrc posted Oct 11, 2021
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About zParms Emil.Kotrc@broadcom.com zParms, also known as DSNZPARMs, SYSPARMS, or just subsystem parameters, are crucial configuration parameters for a Db2 for z/OS subsystem that define the operating characteristics. There are more (used to be) than 300 zParms and they've come a long history of additions, removals, and default changes. Do you ever have a chance to review them since they were initially implemented in your shop? Do you have a chance to monitor what is new in this space? Changes in zParms may have significant impact on the entire subsystem and because of that proper planning and testing is always important, and unfortunately not always simple. ...
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Seeking Your Participation in Analyst Research for IBM Db2, Informix and/or Netezza

By Amanda Clampitt posted Sep 21, 2021
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Gartner has kicked off Magic Quadrant research for the Cloud Database Management Systems. We are seeking delighted IBM Data and AI users who will participate in the Gartner Magic Quadrant research. Participation will only take about 15-20 minutes of your time , and your answers will be aggregated anonymously: Gartner will not publish your name, nor your organization's name. Why participate? This is an excellent way for you to: 1) help shape market opinion about IBM products, 2) help your industry peers learn from your experience, and 3) help our product teams learn from your product experience from the published Magic Quadrant. To ...
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