Thursday, June 30, 2011

The military, the space, the mainframe, and YOU

On Tuesday - while flying - I was reading the new edition of "Informatik Spektrum", the journal of the German Computer Science Association "Gesellschaft für Informatik", GI. One of the articles was meant as discussion starter and was about why and how to lecture mainframe skills at German universities. It described the key benefits of using a System z or mainframe and was showing how mainframes are spearheading technology evolution.

I was reminded of that article this morning again when reading this press release from last month, IBM validates Obsidian's Longbow for DB2 pureScale Stretch Clusters. I had written about a pureScale stretch cluster before, it is a geographically dispersed cluster with parts of the cluster at different locations. In the press release they talk about that the Longbows, the technology to bridge distances for Infiniband, has been developed for the military. We all know that geographically dispersed clusters have been available for years on the mainframe only (GD Parallel Sysplex).

The point I wanted to make is that it is interesting to see what technology trickles down the chain and eventually reaches "the regular guy". In this case it was high-end cluster and networking technology that became available in the "distributed database world". What will be next? Watch the mainframe or the stars...

Friday, June 17, 2011

DB2 Merge Backup: When some deltas make a full

I sometimes teach Data Management at university and one topic is backup strategies. We then discuss what is needed for a point-in-time recovery and what can be done to minimize the time needed for the recovery process. Full backups, incremental backups, delta backups, etc. are things to consider. Well, in a production environment having adequate maintenance windows to periodically take full backups, even online backups, could be a problem.

Some days ago DB2 Merge Backup become available. It combines incremental and delta backup to compute a full backup, so that taking such a full backup can be avoided. I just checked the product web page and a trial version is available. System requirements are DB2 LUW 9.5 or DB2 9.7 and it runs on most platforms.

Thursday, June 16, 2011

Friday, June 10, 2011

Friday Fun: What people drink on the airplane...

Earlier this week when flying back I had some spare minutes and actually read the fineprint on the back of my boarding pass. The section "Dangerous goods in passenger baggage" notes that, among others, poisonous substances and radioactive materials are prohibited. However, at the bottom it is pointed out that, among others, this rule does not apply to alcoholic drinks. Well, that explains the behavior and facial expression of some fellow travelers...

Wednesday, June 8, 2011

DB2: What does the error code mean?

Sometimes I run into a DB2 error that I don't know or there is a reason code given for which I don't know what it means. Of course, going to the DB2 Information Center and searching for, e.g., SQL5099N, is a solution. However, I am not always online or have a local copy of the Information Center available. But there is a simple solution close by: DB2 itself.

When you use the DB2 Command Line Processor (CLP), there is a small help section (try the "?"). Typing in the question mark and the error code, DB2 reveals the full error message including an explanation of reason codes and the so-called user response.

> db2 "? sql5099n"
SQL5099N  The value "" indicated by the database configuration
      parameter "" is not valid, reason code "".


The value of the named parameter is not valid for one of the following

The requested change is not made.

User response:

Resubmit the command with a valid value for the named parameter.

sqlcode: -5099

sqlstate: 08004

Life can be easy, even (especially?) when offline...