A Condensed 35-Year History of DB2 for z/OS (...and Db2 for z/OS)

Let's go back in time... over three decades ago... back to the wild and woolly 1980s! And watch our favorite DBMS, DB2, grow up over time.

DB2 Version 1 Release 1 was announced on June 7, 1983, and it became generally available on Tuesday, April 2, 1985. I wonder if it was ready on April 1st but not released because of April Fool’s Day? Initial DB2 development focused on the basics of making a relational DBMS work. Early releases of DB2 were viewed by many as an “information center” DBMS, not for production workloads, like IMS was.

Version 1 Release 2 was announced on February 4, 1986 and was released for general availability a month later on March 7, 1986. Can you imagine waiting only a month for a new release of DB2 these days? But that is how it happened back then. Same thing for Version 1 Release 3, which was announced on May 19, 1987 and became GA on June 26, 1987. DB2 V1R3 saw the introduction of DATE data types.

You might notice that IBM delivered “releases” of DB2 back in the 1980s, whereas today (and ever since V3) there have only been versions. Versions are major changes, whereas releases are not quite as significant as a version.

Version 2 Release 1 was announced in April 1988 and delivered in September 1988. Here we start to see the gap widening again between announcement and delivery. V2R1 was a significant release in the history of DB2, a bellwether of sorts for when DB2 began to be viewed as capable of supporting mission-critical, transaction processing workloads. Not only did V2R1 provide significant performance enhancements but it also signaled the introduction of declarative Referential Integrity (RI) constraints.

No sooner than V2R1 became GA than IBM announced Version 2 Release 2 on October 4, 1988. But it was not until a year later that it became generally available on September 23, 1988. DB2 V2R2 again bolstered performance in many ways. It also saw the introduction of distributed database support (private protocol) across MVS systems.

Version 2 Release 3 was announced on September 5, 1990, and became generally available on October 25, 1991. Two very significant features were added in V2R3: segmented table spaces and packages. Segmented table spaces quickly became a de facto standard and packages made DB2 application programs easier to support. DB2 V2R3 is also the version that beefed up distributed support with Distributed Relational Database Architecture (DRDA).

Along comes DB2 Version 3, announced in November 1993 and GA in December 1993. Now it may look like things sped up again here, but not really. This is when the early support program for DB2 started. Early support was announced in March 1993 and delivered to customers in June 1993. V3 greatly expanded the number of buffer pool options available (from 5 pools to 80), and many advances were made for DB2 to take better advantage of the System 390 environment, including support for hardware-assisted compression and hiperpools. It was also V3 that introduced I/O parallelism for the first time.

Version 4 signaled another significant milestone in the history of DB2. It was highlighted by the introduction of Type 2 indexes, which removed the need to lock index pages (or subpages, now obsolete). Prior to V4, index locking was a particularly thorny performance problem that vexed many shops. Data Sharing made its debut in V4, too, and with it, DB2 achieved new heights of scalability and availability allowing users to upgrade without an outage and to add new subsystems to a group “on the fly.” DB2 V4 also introduced stored procedures, as well as CP parallelism.

In June 1997 DB2 Version 5 became generally available. It was the first DB2 version to be referred to as DB2 for OS/390 (previously it was DB2 for MVS). Not as significant as V4, we see the trend of even-numbered releases being bigger and more significant than odd-numbered releases (of course, that is just my opinion). V5 was touted by IBM as the e-business and BI version. It included Sysplex parallelism, prepared statement caching, reoptimization, online REORG, and conformance to the SQL-92 standard.

Version 6 brings us to 1999 and the introduction of the Universal Database term to the DB2 moniker. The “official” name of the product became DB2 Universal Database for OS/390. And the Release Guide swelled to over 600 pages! Six categories of improvements were introduced with V6 spanning object-relational extensions, network computing, performance and availability, capacity improvements, data sharing enhancements, and user productivity. The biggest of the new features were SQLJ, inline statistics, triggers, large objects (LOBs), user-defined functions, and distinct types.

Version 6 is also somewhat unique in that there was this “thing” typically referred to as the V6 refresh. It added functionality to DB2 without there being a new release or version. The new functionality in the refresh included SAVEPOINTs, identity columns, declared temporary tables, and performance enhancements (including star join).

March 2001 brings us to DB2 Version 7, another “smaller” version of DB2. Developed and released around the time of the Year 2000 hubbub, it offered much-improved utilities and some nice new SQL functionality including scrollable cursors, limited FETCH, and row expressions. Unicode support was also introduced in Db2 V7.

DB2 Version 8 followed, but not immediately. IBM took advantage of Y2K and the general desire of shops to avoid change during this period to take its time and deliver the most significant and feature-laden version of DB2 ever. V8 had more new lines of code than DB2 V1R1 had total lines of code!

With DB2 9 for z/OS, we drop the “V” from the name. Is that in response to Oracle’s naming conventions? Well, we do add a space between the DB2 and the version number because we don’t want to talk about DB-twenty-nine! A lot of great new functionality comes with DB2 9 including additional database definition on demand capabilities, binary data types, and a lot of new SQL capabilities including OLAP functions and EXCEPT/INTERSECT. But probably the biggest new feature is pureXML, which allows you to store DB2 data as native XML. The XML is stored natively as a new data type that can be searched and analyzed without the need to reformat it. The approach was novel in that it  supports native XML, basically enabling dual storage engines.

And that brings us to DB2 10 for z/OS. This version of DB2 was built to take advantage of many zEnterprise (the latest new mainframe at the time) features to deliver scalability. Examples include improved compression, cache optimization, blades for running the Smart Analytics Optimizer, etc. 

Additional capabilities included many performance improvements (BIND, IN-list, utilities, etc.), hash organized table spaces, high-performance DBATs (DDF threads) forced to use RELEASE COMMIT, parallel index updating, efficient caching of dynamic SQL with literals, temporal data support, safe query optimization, improved access path hints, access to currently committed data, new TIMESTAMP precision and time zones, and buffer pool options for pinning objects in memory.

In October 2013 we got another new version, DB2 11 for z/OS. Click on that link if you want all the details, but some highlights included transparent archiving, global variables, improved SQL PL, APREUSE(WARN), significant utility improvements, DROP COLUMN support, and JSON support with IBM BigInsights.

And that brings us to the present day, with DB2 12 for z/OS as the current (and soon to be only) supported version of Db2. Released for general availability in October 2016, DB2 12 for z/OS abandons the traditional new release cycle that IBM has followed for decades, adopting a new continuous delivery model. New functionality is now delivered in Function Levels (FLs) that are easily applied and delivered much more rapidly than in the past. Indeed, the current Db2 function level is FL506, which means there have been 6 new function levels added since 2016.

Version 12 brought with it a plethora of new capabilities including virtual storage enhancements, optimization improvements, and improved control over the introduction of new SQL capabilities. DB2 12 for z/OS delivered many improvements for both application development and database administration. Examples of new application capabilities include:

• Additional support for triggers, arrays, global variables, pureXML, and JSON
• MERGE statement enhancements
• SQL pagination support
• Support for Unicode columns in an EBCDIC table
• Piece-wise deletion of data
• Support for temporal referential constraint
• More flexibility in defining application periods for temporal tables
• PERCENTILE function support
• Resource limits for static SQL statements
• Db2 REST services improve efficiency and security
• DevOps with Db2: Automated deployment of applications with IBM UrbanCode Deploy

Examples of new DBA and SYSADM capabilities include:

• Installation or migration without requiring SYSADM
• Improved availability when altering index compression
• Online schema enhancements
• Improved catalog availability
• Object ownership transfer
• Improved data validation after running DSN1COPY
• Automatic start of profiles at Db2 start
• Increased partition sizes and simplified partition management for partition-by-range table spaces with relative page numbering
• Ability to add partitions between existing logical partitions
• UNLOAD privilege for the UNLOAD utility
• Temporal versioning for Db2 catalog tables
• Statistics collection enhancements for SQL performance    

Of course, these are just some of the V12 improvements; there are many more (as well as all of the Function Level improvements)!

Then sometime in the middle of 2017, IBM decided to change the name of DB2 by making the uppercase B a lowercase b. So now the name of our beloved DBMS is Db2. Nobody has been able to explain to me what the benefit of this was, so don’t ask me!

The Bottom Line

I worked with DB2 way back in its Version 1 days, and I’ve enjoyed watching DB2 grow over its first 35 years. Of course, we did not cover every new feature and capability of each version and release, only the highlights. Perhaps this journey back through time will help you to remember when you jumped on board with Db2 and relational database technology. I am happy to have been associated with Db2 (and DB2) for its first 35 years and I look forward to many more years of working with Db2… 

IDUG NA 2020 Conference Cancelled

I just received an e-mail notifying me that the 2020 IDUG Db2 Tech Conference scheduled for the week of June 7th in Dallas, TX has been canceled. This is the first time that IDUG has had to cancel a conference, but I have to congratulate the Conference Planning Committee and Board of Directors for making this difficult, but absolutely correct decision.

The email went on to say that IDUG is exploring all of its options for rescheduling the conference for a future date. And they assured all speakers that their sessions are still being held on the grid... so if you want to speak if and when the conference gets re-scheduled, you can!

The global COVID-19 pandemic has impacted all of our daily lives and for the Db2 community, this is just one more reminder of how pervasive this impact has been.

Let's all keep the faith and do our part (stay home, wash your hands) to shorten the duration of this global pandemic...

And Long Live Db2!!!

A Guide to Db2 Performance for Application Developers

DBAs: are you looking for a way to help train your developers to code more efficient Db2 application programs? 

Programmers: do you want to understand the best practices for writing high-performing Db2 applications?

Well, my latest book, A Guide to Db2 Performance for Application Developers, is just what you are looking for! Available in both printed and eBook formats, this is the book you need to assure that you are building effective, efficient Db2 applications.

This book will make you a better programmer by teaching you how to write efficient code to access Db2 databases. Whether you write applications on the mainframe or distributed systems, this book will teach you practices, methods, and techniques for optimizing your SQL and applications as you build them. Write efficient applications and become your DBA's favorite developer by learning the techniques outlined in this book!

The methods outlined in this book will help you improve the performance of your Db2 applications. The material is written for all Db2 professionals, whether you are coding on z/OS (the mainframe) or on Linux, Unix or Windows (distributed systems). When there are pertinent differences between the platforms it is explained in the text.

The focus of the book is on programming, coding and developing applications. As such, it does not focus on DBA, design, and data modeling issues, nor does it cover most Db2 utilities, DDL, and other non-programming related details. If you are a DBA, the book should still be of interest to you because DBAs are responsible for overall Db2 performance. Therefore, it makes sense to understand the programming aspect of performance.

It is important also to understand that the book is not about performance monitoring and tuning. Although these activities are important, they are typically not the domain of application developers. Instead, the book offers guidance on application development procedures, techniques, and philosophies. The goal of the book is to educate developers on how to write "good" application code that lends itself to optimal performance. By following the principles in this book you will be able to write code that does not require significant remedial, after-the-fact modifications by performance analysts. If you follow the guidelines in this book your DBAs and performance analysts will love you!

The assumption is made that the reader has some level of basic SQL knowledge and therefore it will not cover how to write Db2 SQL code or code a Db2 program. It is also important to point out that the book does not rehash material that is freely available in Db2 manuals that can be downloaded or read online.

What you will get from reading this book is a well-grounded basis for designing and developing efficient Db2 applications that perform well.

You can order your copy of A Guide to Db2 Performance for Application Developers today at:

• Bookbaby
• Amazon
• Barnes & Noble

Every Db2 Article I've Written

I've written a lot of articles on Db2 topics over the years and I try to keep everything I've written available over the web. Some of the older articles may not be as applicable today as they were in the past, but I still try to keep them available in case somebody remembers reading something and they want to be able to find it again. 

So, if you are ever want to find a Db2 article of mine that you've read and want to see again, try the following link:

http://www.mullinsconsulting.com/art-db2.html

That page contains all of the Db2 articles that I've written and most of them have links to the full article. It is in reverse chronological order...

And just for fun... here's a picture of the old demo floppy disk that used to come with Db2 back in the day!

Will I See You at SHARE in Fort Worth 2020?

I hope you’ve already made your plans to be there, but if you haven’t there’s still time to get your manager’s approval, make your travel plans, and be where all the in-the-know IT folks will be the last week of February, the SHARE conference in Fort Worth, Texas!

If you’ve ever attended a SHARE conference before then you know why I’m looking forward to this event. With 300+ industry speakers, 500+ sessions and 1,000+ attendees, SHARE offers a world of phenomenal educational opportunities delivered by renowned industry leaders. If you attend, you can benefit from user-driven technical sessions, insights from colleagues, and hardware and software product education all in one place. SHARE attendance guarantees you access to the latest enterprise IT news, prominent industry leaders — including IBM executives — and product highlights on emerging technologies, bringing priceless value to your daily work.

The Spring 2020 event offers more educational opportunities and training than ever before, including content that spans 8 IT disciplines, including:

• Application Development
• Database Systems
• Middleware
• Networks
• Operating Systems (z/OS, z/VM, Linux)
• Security
• Storage
• Systems Management

SHARE began as the first-ever enterprise IT user group way back in 1955… but it has continued to grow and expand over the years> Today it offers an unparalleled opportunity to learn about enterprise IT and to interact with your peers.

What Will I Be Doing SHARE?

As usual, I hope to attend many different sessions to learn what is new out there, especially with regard to my core areas (mainframe and Db2). Check out the agenda here.

I also will be delivering a Lunch and Learn session this year, sponsored by Infotel, on Tuesday, February 25, 2020. This presentation, titled Improving Db2 Application Quality for Optimizing Performance and Controlling Costs, will be presented with a free lunch! So be sure to sign up, then come eat and at the same time, learn about the impact of DevOps on database. I’ll talk about the issues and trends then Colin Oakhill of Infotel will discuss how their SQL quality assurance solutions can aid the DevOps process for Db2 development.

You can RSVP for Lunch and Learn sessions by using the link provided during the registration process. Pre-registration is highly encouraged and space is available on a first-come, first-served basis. If you have already registered and did not RSVP, you can log in to your registration and add your RSVP.

If you have not RSVPed you can still attend the Lunch and Learn session, on a first-come, first-serve basis. Seating opens up to everyone at 12:35 p.m. (10 minutes prior to the session start time).

Later that evening (Tuesday) on the second day of the SHARE expo hall I'll be hanging at the Infotel booth, so if you have any questions we didn’t answer in the Lunch n’ Learn session, you can ask us at the Infotel booth. Be sure to stop by and say hello, take a look at Infotel’s SQL quality assurance solutions for Db2 for z/OS, and register to win one of 2 of my Db2 application performance books that will be raffled off. If you win, be sure to get me to sign your copy!

The Bottom Line

SHARE is the place to be this February 2020 to learn all about what’s going on in the world of enterprise computing. I hope to see you in Fort Worth for SHARE… and if you are going, be sure to track me down and say “Howdy!”