Category Archives: Uncategorized

(Originally posted 2006-02-22.) I’m deeply involved in a nice complex study at one of my favourite clients at the moment – so I’ve just come up for air for half an hour or so. So I’m catching up on blogging about interesting APARs. So APAR PK15890 is my second SQL Access Path Enhancement of theContinue reading “SQL Access Path Enhancement – Second of the day”

(Originally posted 2006-02-22.) APAR OA14839 documents Omegamon support for 2107 (DS8000) devices.

(Originally posted 2006-02-22.) APARs OA14769 and OA14340 document changes to the SMF 30 record. Whether you call them enhancements or fixes depends on your perspective… APAR OA14769 is marked FIN which means no fix is immediately available, but one is expected some time in the next 24 months. SMF30MES should be set to ’02’x wheneverContinue reading “Two SMF Type 30 APARs”

(Originally posted 2006-02-22.) DFSMS APAR OA15034 documents a condition where some controllers support MIDAWs and other controllers don’t. Where a tablespace spans these two kinds of controllers this APAR is important. MIDAWs (Modified InDirect Access Words) are a new channel programming construct on System z9-109 processors which can improve the efficiency of FICON channel programsContinue reading “MIDAWs APAR – Mixed Control Units”

(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”