Articles & Content

Robert Catterall

Robert Catterall is a well-known DB2 z/OS expert. He is a regular speaker at IDUG events and a Past President of IDUG

Note: The content of this blog is the opinion and thoughts of the blogger and does not necessarily represent the opinions of IDUG and should not be construed as reflecting official positions of the IBM Corporation. .

 

 
Db2 12 for z/OS - Let's Talk About MAXDBAT in ZPARM"ZPARMs" is a reference to the parameters in the Db2 for z/OS module called DSNZPARM - these are essentially the configuration parameters for a Db2 subsystem. Two of the ZPARMs that are closely related to each other are CONDBAT and MAXDBAT. CONDBAT specifies the maximum number of connections that ne…
The Two Aspects of Db2 for z/OS Support for JSON DataJSON (JavaScript Object Notation) is a form of data representation that is popular with people who develop what you might call "very modern" applications, including those that are cloud-based and those that have a mobile front-end. One reason this is so: a JSON document is easy for a program (or a p…
Db2 for z/OS - Talking About APPLCOMPAT (Part 2)Last month, I posted to this blog part 1 of a 2-part entry on the APPLCOMPAT option of the Db2 for z/OS BIND PACKAGE command. In that entry I covered several aspects of APPLCOMPAT. In this part 2 piece, I will focus on one particular matter pertaining to APPLCOMPAT - namely, the management of this o…
Db2 for z/OS - Talking About APPLCOMPAT (Part 1)The Db2 for z/OS package bind option APPLCOMPAT is not new - it was introduced with Db2 11. Even so, I think that now is a good time to spend some time thinking about APPLCOMPAT, for two reasons: 1) I've encountered some misunderstandings pertaining to APPLCOMPAT, and I'd like to clear those up; and…
Db2 for z/OS: IIPHONORPRIORITY and zIIP offloadThere is something I have encountered a couple of times (most recently, just a month ago) that can have a negative performance impact on a Db2 for z/OS system, and it's something of which quite a few Db2 people are, I think, unaware. I'm referring here to the setting of a z/OS parameter called IIPHO…
Db2 12 for z/OS Statistics Profiles: Just What the Optimizer OrderedHere is an interesting story for you: not long ago, an analytics-type query was executed on a Db2 for z/OS system that had recently been migrated to Db2 12. The query was cancelled after it had run for 23 hours. A DBA noticed that there was a row for a table targeted by the query in SYSIBM.SYSTABLES…
A Case Study: Implementing a Db2 for z/OS Implicit Trusted ConnectionI've been interested in the role and trusted context features of Db2 for z/OS for a long time (I posted a two-part blog entry on the topic back in 2011). Theory is nice, but what about practice? Recently, I had an opportunity to assist a DBA in implementing implicit trusted connection functionality …
Db2 for z/OS: Isolating REST Client Activity in Db2 Monitor Accounting ReportsIn an entry posted to this blog some years ago, I described the form of a Db2 monitor-generated accounting report that I most like to use to get an overall view of application activity in a Db2 for z/OS environment: an accounting long report with data ordered by connection type (here, I am using ter…
A Case Study: Measuring the Impact of Db2 for z/OS Buffer Pool ChangesNot long ago, a Db2 for z/OS administrator contacted me with a request. His team had made some changes to the buffer pool configuration in their production Db2 environment (the overall size of the buffer pool configuration was increased to reduce read I/O activity, and greater use was made of large …
Db2 for z/OS Partitioned Table Spaces: How the Number of Partitions can Impact PerformanceThis past summer, I delivered a couple of presentations at a meeting of a regional Db2 users group in the USA. During the lunch break, I shared a table with a member of the Db2 for z/OS support team at a large financial institution. He told me an interesting story. At his site, the Db2 for z/OS team…