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 for z/OS Buffer Pools: Index Root Pages and the Data Management ThresholdSometimes, a change in the way Db2 for z/OS manages its resources is introduced, and the change "flies under the radar" (i.e, it escapes the notice of most Db2 users) because it is relatively small in terms of scope and impact and is not widely highlighted in the product documentation, and it delive…
Db2 for z/OS Buffer Pools - Time to Give AUTOSIZE(YES) a Try?Db2 9 for z/OS became generally available back in 2007. In the years since, most of the features introduced with Db2 9 have been broadly put to use. An interesting exception is the auto-sizing of buffer pools, implemented via the AUTOSIZE(YES) option of the -ALTER BUFFERPOOL command. Based on my exp…
Another Db2 for z/OS Blog You Should Check OutIf you're reading this, it's probably because you've found blogs to be a useful source of technical Db2 for z/OS information. I want to direct your attention to one of the newer kids on the Db2 blog block: Db2 for z/OS News from the Lab. What makes the Db2 for z/OS News from the Lab blog particular…
Db2 for z/OS: CACHEPAC is Another ZPARM You Should CheckSometimes, the default value of a Db2 ZPARM parameter is changed to reflect new realities of Db2 workloads and of systems on which Db2 for z/OS runs. When that happens, a Db2-using organization may stick with the old default value for the ZPARM, and going that route can have a negative impact on the…
Db2 for z/OS: DDF, zIIP Engines, and SMT2SQL statements executed by way of the Db2 for z/OS distributed data facility (DDF) are not, of course, the only workload that uses zIIP MIPs, but in my experience this does tend to be the main driver of zIIP utilization in a z/OS system on which Db2 runs. I posted an entry to this blog, a few years …
Db2 12 for z/OS and Insert Algorithm 2: Faster, More-Efficient INSERTs than Ever BeforeNear the end of the blog entry I most recently posted prior to this one, I mentioned that a specification of MEMBER CLUSTER for a Db2 for z/OS universal table space could help maximize INSERT throughput and efficiency, in situations where the importance of that objective outweighs that of keeping da…
Db2 12 for z/OS SQL Enhancements: Result Set PaginationIn this second of a series of entries on my favorite SQL-related enhancements provided via Db2 12 for z/OS (and "Db2," versus "DB2," is officially the new form of the product name), I will describe useful functionality pertaining to result set pagination (my first post in this series covered piece-w…
Db2 for z/OS: Opportunities for CPU Efficiency When Data Clustering is not a PriorityNot long ago, a veteran Db2 for z/OS DBA contacted me with an interesting question. He had, in the system he supported, a table with a clustering index, and he wanted to know how he could get Db2 to act, with regard to INSERT operations and also with regard to executions of the REORG utility, as tho…
Db2 12 SQL Enhancement: Temporal Logical TransactionsTemporal data support, introduced with Db2 10 for z/OS, is one of the more interesting SQL-related Db2 enhancements delivered in recent releases of the DBMS. Temporal data support comes in two flavors (which can both be utilized for a single table): business-time temporal and system-time temporal. W…
Db2 12 for z/OS: Enhanced Lock Avoidance in Data Sharing EnvironmentsIn the last entry posted to this blog, I described the mechanisms (including PUNC bits and commit log sequence numbers, aka CLSNs) used by Db2 for z/OS for lock avoidance purposes (lock avoidance here refers to a capability whereby Db2 can, in many cases, verify the committed state of a data value w…