DB2PORTAL Blog

No Alphabetic Characters Wanted

noreply@blogger.com (Craig S Mullins) — Wed, 25 Jun 2008 16:03:00 +0000

Here is a question that was posed to me recently:

Q: We have a CHAR(10) column that cannot contain alphabetic characters. How can we make sure that the letters A thru Z are not allowed.

A: Well, think about the characteristics of alphabetic characters versus the other "things" that can be stored in a CHAR column. One thing that separates an alphabetic letter from numbers, punctuation, etc. is that there are upper and lower case versions (e.g. A, a). So, you could use the following predicate to preclude alphabetic characters from being accepted:

LOWER(:string) = UPPER(:string)

Of course, you will not be able to put this into a CHECK constraint because of restrictions on their content (for example, you cannot use function in a CHECK constraint). But you could use this in SQL statements and as a check in your programs before allowing data to be inserted or modified in your CHAR(10) column.

Anyone else have any other ideas?

IBM Rules the Middleware Roost

noreply@blogger.com (Craig S Mullins) — Mon, 16 Jun 2008 20:43:00 +0000

Have you seen Gartner's latest report on the middleware market?

The Gartner middleware market numbers were reported in a recent article in eWeek. Evidently, the worldwide application infrastructure and middleware software market revenue totaled $14.1 billion in 2007, a 12.9 percent increase from 2006 revenue of $12.5 billion.

Now that is quite healthy growth in what is a somewhat slow market. And right there at the top of the pile is IBM with a 28.9 percent share of what Gartner identifies as the AIM market...BEA Systems came in second with 9.3 percent of the market, followed by Oracle with 8.5 percent. However, Oracle now owns BEA and will benefit from BEA's market share (next year).

Oracle will likely continue its acquisitive ways, but IBM has not been silent on the acquisition front lately either. So I'm guessing that next year IBM will retain its #1 position with Oracle coming in solidly at #2.

For 2007, though, in terms of growth, Microsoft and Software AG posted impressive gains. Among the big enterprise software vendors, Microsoft came in at 41.6 percent revenue growth year over year. And Software AG showed strong growth with a 107 percent increase from 2006.

This is a market segment, like database software, where a small number of big players own most of the market. However, it is not quite as monopolized as the database market where three players (IBM, Oracle, and Microsoft) dwarf the rest of the field. The top five middleware vendors hold over 50 percent of the overall market and Gartner indicates that the big players are slowly eroding market share from the smaller vendors.

On The Road Again

noreply@blogger.com (Craig S Mullins) — Mon, 09 Jun 2008 06:29:00 +0000

I will been traveling extensively in June this year (2008). Last week I traveled to Phoenix to speak to the American Express Information Summit on the topic of regulatory compliance and its impact on data management and database administration. And I also spoke at the Los Angeles Area DB2 User Group on DB2 performance tuning and database trends.

This week (the second week of June) I will be traveling to Washington, DC to speak to the Baltimore-Washington DB2 User Group (BWDUG) on June 11th to deliver "The Impact of Regulatory Compliance on Database Administration." And then, later in the week, June 13th, I will be in Tampa to speak on the topic on database auditing to the Tampa Bay Relational User Group (TBRUG).

And the week after that I will be speaking to the Chicago chapter of (DAMA) on June 18th, on the topic of "Managing Data For Long Retention Periods."

So, if you are in one of the regions where I'll be speaking, I hope you can take the time to attend. And if not, you can always keep track of my speaking schedule on my web site at http://www.craigsmullins.com/speak.htm.

Database Archiving Trends and Best Practices

noreply@blogger.com (Craig S Mullins) — Wed, 28 May 2008 17:11:00 +0000

Just a short note to promote my upcoming webinar, this Friday, May 30, 2008 at 10:30 AM CST. The webinar is titled Database Archiving Trends and Best Practices and it will cover a variety of trends and issues that are contributing to the growing requirement within enterprises to archive database data for long-term retention and preservation.

I'll touch on trends such as regulatory compliance issues, e-discovery, operational performance improvement, and retiring legacy applications. After examining the forces driving the need to archive database data, we'll look at the requirements for implementing database archiving appropriately, and walk thru an example using TITAN Archive.

If your databases are bursting at the seams, your organization is experiencing compliance-related troubles and/or lawsuits, or you need to figure out how to sunset an old database application or two, this presentation will provide guidance, advice, and a workable template for you to follow.

I hope you can find the time to attend!

New IBM RedBook on Dimensional Modeling

noreply@blogger.com (Craig S Mullins) — Mon, 26 May 2008 20:17:00 +0000

Just a quick post today (Memorial Day in the USA) to inform you about a new IBM RedBook on dimensional modeling. If you are working with data warehousing applications, writing analytical queries, or in any way dealing with databases and dimensional models, this free RedBook is well worth downloading and reading.

It is titled Dimensional Modeling: In a Business Intelligence Environment. The book is not intended to be an academic treatise, but a practical guide for implementing dimensional models oriented specifically to business intelligence systems.

Particularly interesting are the case studies in Chapters 7 and 8 that walk you through BI implementations.

Download it today... and enjoy it at your leisure.

Another IDUG in the Books

noreply@blogger.com (Craig S Mullins) — Thu, 22 May 2008 22:32:00 +0000

Well, here it is late in the day on May 22, 2008 and the IDUG North American conference is officially over. And, of course, it was another successful conference!

From the start of the festivities on Monday with the welcome address and keynote session (which can be downloaded here) to the traditional IBM panel and closing session today, IDUG offered consistently high quality education and unparalleled networking opportunities for DB2 professionals.

Usually I blog about the sessions I attend but this year I used Twitter instead to micro-blog the highlights of the sessions I attended right from the sessions using my Treo. I hope you followed my Twitter posts (Tweets, they're called). But even if you didn't it is not too late to follow me on Twitter at www.twitter.com/craigmullins.

One thing I would like to mention, though, is that it looks like the Special Interest Groups are finally being taken seriously. Used to be that the SIGs were put on the schedule late in the day and almost nobody showed up. This year, there were more SIGs and they were scheduled at better times throughout the day - and people showed up for them... and participated. I very much enjoyed participating as a subject matter expert in the Changing Role of the DBA SIG, and I attended a couple other SIGs that were very worthwhile, too!

If you didn't get to the conference this year (or even if you did and missed a few sessions) IDUG will be making audio recordings from this year’s technical sessions available on the IDUG Online Learning Center in July 2008. Full-conference attendees get twelve complimentary downloads with their registration. If you did not attend, individual sessions can be downloaded for a nominal fee. You can check out the IDUG Online Learning Center here (again, that is where the session downloads will be).

And if you just want to voyeuristically take a look at what you missed, you can check out photos from this year's conference online at http://idug2008northamerica.site.shutterfly.com/.

Thanks for another great event, IDUG... and hopefully we'll see you next year in Denver, CO (May 11-15, 2009).

Twitter

noreply@blogger.com (Craig S Mullins) — Wed, 14 May 2008 20:16:00 +0000

After listening to John Dvorak (on Cranky Geeks) talk about Twitter I decided to try it out this week. And I quickly found some other DB2 folks out there twittering (Willie, Troy).

I put up Twitter feeds on my home page and here on my blog, too (it is over there on the right). I'm not sure if I'll stick with Twittering long-term, but I probably will - it is a bit addictive. If you want to try it out yourself, click on the follow me on Twitter link over on the right hand side of this page - or click here if you don't want to be bothered tracking it down over there!

I noticed, too, that Willie Favero will be twittering during the upcoming IDUG conference next week and since I can recognize a good idea when I hear/read/see one (good idea, Willie), I think I'll try it, too. So sign up on Twitter before next week if you want to virtually attend IDUG by following our twittering.

Database Archiving Trends and Best Practices Webinar

noreply@blogger.com (Craig S Mullins) — Mon, 12 May 2008 19:35:00 +0000

Just a quick blog entry today to promote my upcoming webinar on May 30, 2008 titled Database Archiving Trends and Best Practices.

A variety of trends and issues are contributing to the growing requirement within enterprises to archive database data for long-term retention and preservation. This webinar will review the trends driving database archiving, including regulatory compliance issues, e-discovery, operational performance improvement, and retiring legacy applications. After examining the driving forces for database archiving, we will walk through the basic steps required to implement best practices based database archiving practice.

If your databases are bursting at the seams, your organization is experiencing compliance-related troubles and/or lawsuits, or you need to figure out how to sunset an old database application or two, this presentation will provide guidance, advice, and a workable template for you to follow.

Enroll today!

On the Road Again

noreply@blogger.com (Craig S Mullins) — Mon, 28 Apr 2008 21:52:00 +0000

If you live in or around Birmingham, Alabama or Dallas, Texas or Phoenix, Arizona I will be in your neck of the woods the next two weeks speaking at the local DB2 user groups.

On April 30th, 2008 I'll be speaking at Alabama DB2 User Group on the topic of Managing Data For Long Retention Periods.

Then, on May 2nd, I mosey on over to Dallas to speak on two topics at the DB2 Forum meeting. I'll cover database auditing in one talk and the other will be my "famous" DB2 Top 10 Lists presentation.

The following week, on May 8th, I'll be in Arizona to discuss The Impact of Regulatory Compliance on Database Administration at SWARUG.

And in my last presentation before IDUG, I'll be giving a shortened version of the regulatory compliance presentation in my hometown of Houston, TX at the Techxans: CIO Speaker Forum.

So maybe I'll see you on the road... and, if not, I hope to see you in Dallas for IDUG the week of May 18 thru 22, 2008. I've got a presenation on data breaches from a database perspective (4 PM on Tuesday), and I'll also be leading a Special Interest Group discussion on the changing role of the DBA (9:15 AM on Thursday). You can see the entire agenda here on IDUG's web site.

My Most Recent DB2 Articles

noreply@blogger.com (Craig S Mullins) — Tue, 22 Apr 2008 20:28:00 +0000

Today I'm posting a quick blog entry to let my readers know about a couple of recent DB2-related articles/columns that I've had published. You can always keep up-to-date on my writings by visiting my web site at http://www.craigsmullins.com/articles.htm.

Any way, the following three articles might be of interest to DB2 for z/OS folks:

Use Real Time Statistics to Automate Your Database Maintenance was published in the April/May 2008 issue of zJournal. This article examines Real Time Statistics (RTS) and the benefits that can be accrued by using RTS. If you aren't using RTS yet, be sure to read this article to learn why you should!

Collecting Histogram Statistics With RUNSTATS was published in the March 2008 issue of DB2 Update. This article discusses one of the many new enhancements that have found their way into DB2 9 for z/OS -- the ability to gather histogram statistics with the IBM RUNSTATS utility.

And finally, the February/March 2008 issue of zJournal contains Much Ado About DB2 Locking. This installation of the z/Data Perspectives column takes a look at the most recent, new locking-related features of DB2 for z/OS.

Happy reading!

The Mainframe Still Rocks!

noreply@blogger.com (Craig S Mullins) — Thu, 17 Apr 2008 21:14:00 +0000

Mainframe Executive, a new publication for CIOs and IT managers in enterprises with IBM mainframe systems, just published a list of 15 reasons to stay on, or move to, a mainframe. The list is a good one, covering reliability, availability, security, resource utilization, scalability, power consumption, staffing concerns, quality, and on and on.

Here is the list for those not inclined to click on the link:

1. Lowest outage costs from highest platform reliability, availability, and serviceability.
2. Lowest security breach risks/costs via most secure design, encryption, etc.
3. Highest resource use efficiency/utilization for mixed commercial workloads.
4. Widest platform scalability supports any workload size, mix, growth.
5. Consolidates many new workloads, extends traditional workload strengths.
6. Top data-serving capacity, performance, value—best Information on Demand host.
7. Highest QoS, best performance with fastest response times.
8. Best enterprise SOA platform; enables fullest reuse of mainframe application assets.
9. Much-improved cost model transformed mainframe economics.
10. Lowest power consumption, cooling, and data center floor space needs.
11. Lowest staffing and support costs for enterprise workloads.
12. Lowest total cost of ownership, total cost per user, and total cost per transaction.
13. Best customer investment protection for any enterprise platform.
14. Lowest business risk platform with best world class support.
15. Healthy, expanding mainframe ecosystem is supporting the platform.

If you are a mainframer this list won't come as any surprise to you... but it can be handy to keep it readily available for the next time someone attempts to convince you that mainframes are already obsolete, or should be.

In fact, maybe you can come up with additional reasons. After reading the list (http://www.mainframe-exec.com/articles/?p=12) feel free to submit comments here with any additional reasons you might come up with!

Also, for those who don't know, Mainframe Executive is published by Thomas Communications, the same folks who publish the excellent bi-monthly z/Journal.

Consider Table Expressions to Improve Performance

noreply@blogger.com (Craig S Mullins) — Thu, 10 Apr 2008 19:11:00 +0000

Table expressions are frequently overlooked as a potential solution for resolving problems using only SQL. Table expressions can be used to force the optimizer to choose a specific processing order.

For example, consider the following query:



SELECT D.DEPTNO,

       MIN(D.DEPTNAME) AS DEPT_NAME,

       MIN(D.LOCATION) AS DEPT_LOCATION,

       SUM(E.SALARY) AS TOTAL_SALARY

FROM   DEPT D,

       EMP E

WHERE  D.DEPTNO = E.WORKDEPT

AND    E.BONUS BETWEEN 0.00 AND 1000.00

GROUP BY D.DEPTNO;

In this query, the detail rows that qualify from each table are joined prior to the GROUP BY processing. In general, there will be more EMP rows than DEPT rows because a department comprises multiple employees. Suppose there were 200 DEPT rows joined to 75,000 EMP rows. The join is done and then the GROUP BY is processed.

Instead, you can use table expressions to force the optimizer to process the aggregations on a table-by-table basis:



SELECT D.DEPTNO,

       D.DEPTNAME,

       D.LOCATION,

       E.TOTAL_SALARY

FROM   DEPT D,

       (SELECT WORKDEPT, SUM(SALARY) AS TOTAL_SALARY

        FROM EMP E

        WHERE E.BONUS BETWEEN 0.00 and 1000.00

        GROUP BY E.WORKDEPT) AS E

WHERE  D.DEPTNO = E.WORKDEPT;

This will produce the same results but it should perform better.

In general, consider using table expressions to pre-filter FULL JOIN tables, to pre-filter null supplying tables of LEFT/RIGHT joins, to separate GROUP BY work, and to generate or derive data.

Updated Stored Procedure RedBook for DB2 V9

noreply@blogger.com (Craig S Mullins) — Thu, 27 Mar 2008 17:55:00 +0000

If you are a stored procedure developer, or a DBA who manages a system with stored procedures - - and you are running DB2 9 for z/OS - - there is an updated RedBook you should download immediately. It is titled DB2 9 for z/OS Stored Procedures: Through the CALL and Beyond. You may have the previous edition, DB2 for z/OS Stored Procedures: Through the CALL and Beyond (SG24-7083)...

This new edition of an all-time favorite RedBook is newly updated to show the changes that have happened to DB2 stored procedures and related tools from V8 to V9. It offers examples and guidelines for developing stored procedures in several languages. You will also find many useful recommendations for setting up and tuning your environment for stored procedures in this free-to-download manual.

And if you are looking for some "stuff" on using Data Studio with stored procedures, this is the place to go... so, it is time to update by downloading this new edition today!

DB2 Developer's Guide Tops Book Poll

noreply@blogger.com (Craig S Mullins) — Wed, 19 Mar 2008 15:23:00 +0000

I learned of some good news today. Evidently my DB2 book, DB2 Developer’s Guide, recently won the favorite book poll conducted by IBM Database Magazine (formerly DB2 Magazine) a couple of months ago… and it won by a substantial margin.

Thanks to everyone who voted for my book… I appreciate your support.

Free Downloadable eBook from IBM Press

noreply@blogger.com (Craig S Mullins) — Tue, 18 Mar 2008 15:24:00 +0000

Pearson and IBM Press have just published a new eBook on IBM database technology that is available for free download. Just follow this link, provide your e-mail, and they’ll direct you to a PDF containing sample chapters from six recently published books.

The information in the eBook comes from the following books:

Understanding DB2: Learning Visually With Examples, Second Edition by Chong, Wang, Dang, and Snow - Chapter 2: DB2 at a Glance: The Big Picture
DB2 9 for Linux, UNIX, and Windows, Sixth Edition by Baklarz & Zikopoulos - Chapter 8: pureXML Storage Engine
Understanding DB2 9 Security by Bond, See, Wong & Chan - Chapter 11: Database Security — Keeping It Current
DB2 SQL PL: Essential Guide for DB2 UDB on Linux, UNIX, Windows, iSeries by Janmohamed, et al - Chapter 3: Overview of SQL PL Language Elements
Mining the Talk by Spangler & Kreulen - Chapter 5: Mining to Improve Innovation
An Introduction to IMS by Meltz, et al - Chapter 18: Application Programming in Java

IBM Press is also offering a 35% discount on these, and other selected titles. But in some cases, the amazon discount is greater than 35%, so if you'd rather buy from amazon.com, simply follow the links in the bulleted list above.

But make sure you download that free eBook... after all, what is better than free?

Q+A: Nulls and DASD

noreply@blogger.com (Craig S Mullins) — Mon, 03 Mar 2008 20:26:00 +0000

Recently, I received the following question, which I will answer today on this blog posting.

Question: Lets say I have a table A which has 500 columns. Out of those 500 columns only 5 columns have been defined as not nullable and the rest have been defined as NULLS allowed. And out of those 500 columns I have found that 300 columns are unused(empty) totally. My business allows me to remove those 300 columns. My doubt is if I remove those 300 empty columns will I save on DASD space occupied by DB2? Will empty columns occupy DASD space?Would be really helpful if you can guide me on this.

Answer: I'm happy to try to help out. First of all, the short answer to your question is "Yes!" Those 500 columns are all consuming valuable disk space. To determine how much space is being consumed, you will need to examine the data type and length assigned to each column and add them up. And to make matters worse, you must add an additional 1 byte to each of them because the columns are nullable.

In DB2, a NULL is stored using a special one-byte null indicator that is "attached" to every nullable column. If the column is set to NULL, then the indicator field is used to record this. Using NULL will never save space in a DB2 database design - in fact, it will always add an extra byte for every column that can be NULL. The byte is used whether or not the column is actually set to NULL.

So, a column defined as CHAR(5) NOT NULL will required five bytes of storage space - but if it is defined as nullable, then it requires six bytes of storage space - five bytes for the data, and one byte for the null indicator.

Given all of this, it would seem that there is a very viable case to be made for you to remove those columns that are not being used. Of course, this means that you will likely have to make changes to any programs accessing that table. Because the table definition will change (fewer columns) you will need new DCLGENs and those will have to be included and bound into your programs. Be sure to factor this additional workload into your planning before moving forward with this change.

The better question to ask is "How the heck did all of the empty columns get put into the table to begin with and how did that design get past the DBAs?"

If you have an answer for that one, please share it by posting your answer in a comment here!

Let's Hear It for COBOL!

noreply@blogger.com (Craig S Mullins) — Wed, 20 Feb 2008 17:02:00 +0000

I know that this blog is supposed to be primarily about DB2, but I like to sneak in mainframe-related topics from time to time. And I read a great article today in Computerworld that I want to share with you. The article, titled Confession of a COBOL Programmer, talks up the need for COBOL coders. Just like with other mainframe technologies, as the baby boomers retire there is an insufficient supply of newbies available to step in and continue the care and feeding of the COBOL legacy.

I've written briefly about COBOL before, in my Data Management Today blog. COBOL is still all over the place and in no danger of dying off. According to the Computerworld article, 75% of the world's businesses data is still processed in COBOL, and about 90% of all financial transactions are in COBOL.

Yet there is a lingering perception "out there" that COBOL is dead (or at least dying). And as far as graduating seniors and new programmers are concerned, COBOL ain't cool! New programmers don't want to learn it and most universities don't teach it in their computer science or information science curricula. Just like the mainframe (which is alive and well, too), COBOL is ignored and a big problem is developing.

Analysts at Gartner estimate that there are 180 billion lines of COBOL code in existence and about 90,000 COBOL programmers. To convert all of that to something else "each programmer will require 100,000 hours to complete the conversion of 2 million lines. That works out to 12,500 eight-hour workdays. If we figure 250 workdays per year (though it’s unlikely any Cobol programmers are settling for just two weeks of vacation per year), these guys should be done in 50 years."

Who knows, when I retire (sometime in the far-off future) maybe I'll hang up a shingle and offer my services as a COBOL coder... after all, that is what I started out doing right out of college (all those years ago)...

Intelligent Automatic Reoptimization? [DB2 9 for z/OS]

noreply@blogger.com (Craig S Mullins) — Tue, 05 Feb 2008 17:34:00 +0000

Most seasoned SQL programmers know that when you use host variables, DB2 may not always come up with the absolutely most optimal access path at bind time. Without knowing the actual values of the host variables the optimizer has to make some best guesses as to how best to satisfy the SQL request.

Furthermore, we know that we can guide DB2 on how best to approach this situation using the REOPT parameter of the BIND command. Prior to DB2 V9, there were three options for REOPT:

REOPT(NONE) – DB2 will not reoptimize SQL at run time.

REOPT(ALWAYS) – DB2 will prepare SQL statements again at run time when the host variable values are known. This enables the DB2 optimizer to formulate the query execution plan using the actual host variable values, which can result in better performing access paths.

REOPT(ONCE) – DB2 will prepare SQL statements only once, using the first set of host variable values, no matter how many times the statement is executed by the program. The access path is stored in the Dynamic Statement Cache (DSC) and will be used for all subsequent executions of the same SQL statement. REOPT(ONCE) only applies to dynamic SQL statements and is ignored if you use it with static SQL statements. This option was introduced in DB2 V8.

What is New in V9?

DB2 9 for z/OS introduces a new REOPT option: REOPT(AUTO). The ideas behind REOPT(AUTO) is to come up with the optimal access path in the minimum number of prepares.

The basic premise of REOPT(AUTO) is to re-optimize only when host variable values change. Using this option, DB2 will examine the host variable values and will generate new access paths only when host variable values change and DB2 has not already generated an access path for those values.

REOPT(AUTO) only applies to dynamic statements that can be cached.

After migrating to DB2 9, consider re-evaluating programs bound specifying REOPT(ALWAYS) and REOPT(NONE). In many cases, switching to REOPT(AUTO) from REOPT(ALWAYS) can produce performance improvement; and in some cases you can use re-optimization with REOPT(AUTO) for programs bound REOPT(NONE) because of the fear of too frequent re-optimization causing a performance hit.

In particular, consider specifying REOPT(AUTO) for SQL statements that at times can take a relatively long time to execute, depending on the values of parameter markers. In particular, you should especially consider doing this when parameter markers refer to non-uniform data that is joined to other tables.

Get Control of Access Path Changes for Dynamic SQL when Migrating to a New Version of DB2

noreply@blogger.com (Craig S Mullins) — Fri, 25 Jan 2008 16:51:00 +0000

Are you making plans to migrate to a new version of DB2? Do you know what impact the access changes for dynamic SQL will have on performance? When migrating to a new DB2 version, access path changes for dynamic SQL are unpredictable – as is the impact those changes will have on application performance. Learn how you can use Bind ImpactExpert to eliminate the unwanted surprises in version migration by performing a “precheck” on dynamic SQL access path changes.

This webinar will be presented by myself (Craig Mullins) and Joe Brockert, Sr. Software Consultant for NEON Enterprise Software. We'll discuss the issues associated with dynamic SQL during a DB2 migration and offer a live demo of Bind ImpactExpert. Join us to see the solution that provides predictability in access path changes.

Enroll by clicking on this link.

Q+A: Locking

noreply@blogger.com (Craig S Mullins) — Wed, 16 Jan 2008 19:59:00 +0000

I get questions e-mailed to me all the time. Although I try to read and answer them all, sometimes I don't. I hope those whom I've ignored over the years will forgive me, but I can't always answer everything (not enough time/energy) and sometimes things get lost or drop through the cracks.

Anyway, at times I will take a question I get and blog about it in Q+A format. Today is one of those days!

The question was: I want to perform a retry on an INSERT under DB2 Z/OS when I get a deadlock/timeout. -911 causes a rollback automatically. Is there a ZPARM or other method of turning this off? I am inserting millions of rows and do not want a rollback to the last commit point.

Here is my answer:

Well, first of all, let me recommend that you minimize the size of your unit of work. If you are inserting millions of rows without a COMMIT you are likely causing locking issues in your environment. The pages you have locked while you are waiting for your millions of inserts to finish are all unavailable to any other user of the table (assuming page locking). That means any data on any page that you have locked cannot be read by anyone else until your unit of work is committed. Any other user, running at the same time as you are, trying to get to any page you have modified, would be getting -911 too.

That being said, you can control whether or not the work is rolled back automatically in CICS (on a thread basis) using an RDO parameter (or RCT if on an ancient CICS). The parameter is called ROLBE (RCT) or DROLLBACK (RDO). If it is set to YES a CICS SYNCPOINT ROLLBACK is issued and a -911 SQLCODE is returned to the program. If NO is coded, a CICS SYNCPOINT ROLLBACK is not issued and the SQLCODE is set to -913. You will have to programmatically either specify COMMIT or ROLLBACK for the unit of work.

In a batch environment you will need to code your programs to periodically issue COMMITs after so many modifications (or using some other method like a timer or loop counter). There is no method I am aware of to automatically control this behavior outside of looking into a third party product (for example, Softbase Checkpoint Restart, and others).

Blog Tagged

noreply@blogger.com (Craig S Mullins) — Wed, 16 Jan 2008 17:54:00 +0000

I have been blog tagged by Willie Favero. Don't worry, its not as painful as it sounds!

Basically, blog-tagging is a game, of sorts, that has been crawling its way through the blogosphere for awhile now. The way it works, when you are tagged by another blogger, you have to write a blog posting about yourself, with 8 things that others might not know. . . and then tag 8 other bloggers.

So here goes:

I am an avid music fan. At last count, I have 5,281 CDs and albums (yes, I still have records). I know exactly how many I have because, geek that I am, I keep a list of them in a Filemaker database that I sync up with my Treo. I need that list on my Treo because, without it, I have been known to buy a CD I already own.
I currently live in Texas, but I was born and raised in Pittsburgh, PA. Go Steelers (we'll get 'em next year)! My Mom, my brother, and his family still live in the Pittsburgh area and I get back to visit them at least once a year.
I've also lived in the Chicago area. When people ask how I like it in Texas after living up North for so long, I tell 'em "I like it. I basically traded snow for humidity, and you don't have to shovel humidity!"
I've written two books - DB2 Developer's Guide and Database Administration: The Complete Guide to Practices & Procedures... and I'm working on co-authoring another one on DB2 performance.
I'm married, and I met my wife while working at PLATINUM technology. Remember them? A lot of good things happened during my days at PLATINUM! In fact...
At one point, I used to write those monthly DB2 tips you DB2 people used to get in the mail from PLATINUM.
I currently write four different columns for industry publications, as well as several blogs.
I own a dog, an English springer spaniel named Jerry... I call him my Jerry Springer spaniel... and two cockatiels.

OK, I guess that means I now have to tag eight others. Willie beat me to the punch on a lot of my favorite DB2 bloggers, though. So I'll tag Peter Armstrong, Chris Foot, Chris Eaton, Trevor Eddolls, Dave Moore, Phil Nelson, Fred Sobotka, and Ralph Wilson.

You folks are now "it"...

History of the Mainframe

noreply@blogger.com (Craig S Mullins) — Tue, 15 Jan 2008 22:29:00 +0000

While researching some items on the web I ran across a couple of interesting mainframe-related sites that I'd like to share with you.

First up, on The History of Computing Project's site, is this entertaining and informative timeline of mainframe history. The timeline starts in 1939 with the creation of the Atanasoff-Berry Computer at Iowa State. If you are looking for historical events in the life of the mainframe, then this is a good place to start. It contains links to information about, and pictures of, some early mainframes including the ENIAC and the IBM 701.

Another interesting mainframe-related page is at Carnegie-Mellon's Software Engineering Institute site. I point it out not because I agree with the "stuff" written there, but because I find it amusing to see the word "LEGACY" stamped over every inch of the page. Wise up! The mainframe is not just legacy, folks!

And finally a nice little article with the proper perspective on mainframe architecture from IBM. I particularly liked the way this article ended:

As the image of the mainframe computer continues to evolve, you might ask: Is the mainframe computer a self-contained computing environment, or is it one part of the puzzle in distributed computing? The answer is that The New Mainframe is both...

STOGROUPs and SMS [DB2 9 for z/OS]

noreply@blogger.com (Craig S Mullins) — Wed, 09 Jan 2008 19:51:00 +0000

With today’s posting we return to our examination of the new features of DB2 9 for z/OS. With V9, DB2 storage groups can be better integrated with SMS storage classes.

Prior to DB2 9, you could only spcify SMS storage classes, data classes, and management classes when using explicit IDCAMS defines. You could use those SMS specifications with your SMS ACS routings, but ACS routines filter on data set names, so those routines could become large and unwieldy if you defined multiple different combinations for different data sets.

The improvement in DB2 9 modifies the CREATE and ALTER STOGROUP statements to utilize SMS classes. This can greatly improve ease-of-use by minimizing the manual effort involved in managing DB2 data sets using DFSMS.

There are three new keywords in the CREATE STOGROUP syntax. You can specify just one, two or even all three of them on one CREATE STOGROUP statement:

DATACLAS - influences characteristics such as the data set control block (DCB), striping, extended format usage, extended addressability usage and so on.
MGMTCLAS – defines data set frequency of volume backups, migration requirement and related tasks.
STORCLAS - define guaranteed spaced and other requirements.

DB2 will not check to verify that the data class, management class, or storage class specified actually exist. In that regard, the parameters are designed to work the same way that the VCAT and VOLUMES parameters have always worked. When the STOGROUP is used to allocate a data set, the specified classes are passed to DFSMS, which does the actual work.

The intent of this posting is not to act as an SMS tutorial. If you wish to investigate the details of SMS in more depth, consult the IBM manual titled -- z/OS DFSMS Implementing System-Managed Storage, SC26-7407.

Additionally, these same parameters have been added to the ALTER STOGROUP statement. When you alter SMS class names of a DB2 STOGROUP, this does not affect the existing data sets. However, if you run the REORG, RECOVER, or LOAD REPLACE utility, DB2 deletes the associated data set and redefines it using the new description of the storage group.

Finally, to accommodate the metadata for these new parameters, three new columns have been added to the SYSIBM.SYSSTOGROUP DB2 catalog table: DATACLAS, MGMTCLAS, and STORCLAS.

On Database Skills and DBA Salaries

noreply@blogger.com (Craig S Mullins) — Thu, 03 Jan 2008 17:54:00 +0000

Just a quick post today to point you over to my Data Management Today blog. I use this blog to talk about data management issues that are not specific to DB2, whereas this blog focuses almost exclusively on DB2 (and mainframe) topics.

But two recent posts at my other blog may be of interest to readers of my DB2 Portal blog. They deal with the topics of employability and pay -- two topics that are near and dear to the heart of IT and database professionals.

Here are links to those posts:

DBA Salary Update - a look at a couple of recent salary surveys
Database Skills Are In Demand - a look at a recent study on IT skills

If you find these posts interesting, subscribe to my Data Management Today blog (via RSS) and/or check in regularly.

Mainframe Career Still a Good Idea!

noreply@blogger.com (Craig S Mullins) — Sun, 30 Dec 2007 05:10:00 +0000

Just a quick post today to point you over to an article that ran in eWeek Magazine titled Big Iron Remains Career Option. Those of us who have worked with mainframes for decades know that mainframes still run the bulk of the mission-critical, high transaction workload for the biggest companies. And we know that you can make a good career out of mainframe development, administration, and management.

But it is good news that others are starting to hear this message.