Category Archives: Uncategorized

(Originally posted 2006-02-22.) First reported for DB2 Version 7 APAR PK17725 documents an enhancement to the access path for EXISTS (also NOT EXISTS) queries… Previously DB2 performed DISTINCT processing, requiring a sort. Now the sort can be avoided as DISTINCT processing is no longer done. Fixes will be made available for Versions 7 and 8.

(Originally posted 2006-02-07.) If you are reporting on DB2 incremental binds, whether through DB2PE/DB2PM, some other reporter, or your own code you might find the number wrong. You know it’s wrong because it plain looks silly.:-) APAR PK16637 describes just such a problem. Note: As of today the fixes are not yet available. The significanceContinue reading “Incremental Bind Number Wrong”

(Originally posted 2006-01-24.) Today we announced the zIIP specialty engine for System z9 109. When I say we I had nothing to do with it, of course. 🙂 I’m in Global Services and we don’t make processors – we only tune them. 🙂 It seems to me zIIPs are going to be more significant thanContinue reading “zIIPs and zAAPs”

(Originally posted 2006-01-24.) As a performance consultant I used to think it was only me that needed to glean configuration information from performance data – because I didn’t want to ask foolish questions of the customer. But gradually (it seems to me) customers have ended up in the same boat as me: What we thoughtContinue reading “Self-Documenting?”

(Originally posted 2006-01-12.) I’m lucky to again be on the agenda at this conference. Here’s a link to the conference website. This is a very good arena for technical education on the mainframe, with many great speakers from the development laboratories, coupled with a number from the field. I always learn a lot – soContinue reading “System z9 and zSeries Technical Conference”

(Originally posted 2006-01-12.) APARs PQ99707, PK07317 and PK08949 document two performance improvements that help WAS applications using the Universal JCC (java) driver. All the enhancements are available for DB2 Version 8. The “CPU cost” one is also marked as available for DB2 Version 7. Higher DB2 CPU costs and longer transaction times are caused whenContinue reading “DB2 Performance Improvements for Websphere Application Server JCC Clients”

(Originally posted 2006-01-12.) Running out of extents for DB2 tablespaces can be a real bore. So installations like to monitor them (and I like to see them too). APAR PK12653 describes a fix to the recording of the number of extents in the SYSTABLEPART Catalog table. This fix is only available for DB2 Version 8.Continue reading “Fix to the way extents are calculated in SYSTABLEPART”

(Originally posted 2006-01-12.) I’m working through the queue of interesting APARs that have been sitting in my in-basket. (I guess it’s a “New Year’s tidying up” thing.) 🙂 Here’s one that relates to workload routing for DDF. It does prereq z/OS R.7 on all members so it won’t be of that much interest to customersContinue reading “Better Routing of DDF Work in a Parallel Sysplex with z/OS 1.7”

(Originally posted 2006-01-04.) APAR PQ91316 documents 4 new Web Services Consumer UDFs – for both Version 7 and Version 8. Being a consumer means the UDF can request services from other providers, rather than serving other requesters. The APAR text itself describes the UDFs, and incorporates an example.

(Originally posted 2005-12-01.) If you ask Performance Trace nicely enough it’ll tell you what statement in a package is consuming all the CPU. Over the past couple of years we’ve been working on code to analyse the DB2 Catalog and PLAN_TABLE tables to do SQL tuning. It’s been an interesting journey – and, I guess,Continue reading “DB2 Catalog and Performance Trace Mismatch”