DB2 Data Sharing Performance for Beginners

(Originally posted 2006-04-06.) I’m strongly considering writing a DB2 Data Sharing For Beginners presentation. In fact I have a proposal in to do just such a thing for the US z/OS Conference (in Orlando in October). Obviously that would be a presentation I’d like to take to eg UKCMG and the EMEA z/OS Conference nextContinue reading “DB2 Data Sharing Performance for Beginners”

Another MIDAWs APAR – Might Improve Its Performance

(Originally posted 2006-04-03.) In this entry I talked about an APAR that fixed an issue with mixed farms of control units, where only some supported MIDAWs. Here’s another APAR. This one could increase the performance benefit of MIDAWs. APAR OA15556 changes the way IDAWs (Indirect Data Access Words) are placed in memory, relative to theContinue reading “Another MIDAWs APAR – Might Improve Its Performance”

More REORG Utility Flexibility

(Originally posted 2006-03-30.) Long ago the DB2 REORG utility traded memory for speed with SORTKEYS and SORTDATA. The latter caused the object being REORGed to be unloaded and externally sorted (eg using DFSORT). (SORTKEYS was similar but for the keys to REORG the indexes.) This is fine if you have the memory to drive eitherContinue reading “More REORG Utility Flexibility”

Some SQL Access Path Improvements

(Originally posted 2006-03-30.) Just briefly, here are some Access Path fixes I’ve been meaning to talk about: PK14923 QUERY COST ESTIMATE IS TOO HIGH IN SOME CASES PK16521 ONE FETCH INDEX ACCESS (I1) NOT USED WITH DUPLICATE PREDICATES PK15143 POOR QUERY PERFORMANCE WHEN SORT MERGE JOIN IS CHOSEN AND MULTIPLE JOIN COLUMNS ARE POSSIBLE ORContinue reading “Some SQL Access Path Improvements”

DB2 As A Web Services Provider

(Originally posted 2006-03-30.) I present at conferences on what I call New World DB2 application performance, by which I mean such things as Stored Procedures, SAP R/3 and BW, Distributed (DDF) and JDBC. I do this because I think us mainframe performance people need to lead conversations on DB2 application performance that actually acknowledge whatContinue reading “DB2 As A Web Services Provider”

Lotus Sametime 7.5 Alpha 2

(Originally posted 2006-03-10.) A little off-topic, perhaps, but I’ve just installed the second Alpha of Lotus Sametime 7.5, IBM’s recently-previewed new instant messaging client. I would’ve liked to have installed the first Alpha but I’ve been working hard on behalf of one of my favourite clients until yesterday. There’s that phrase again, Brian. 🙂 Actually,Continue reading “Lotus Sametime 7.5 Alpha 2”

Useful RedPaper: Coupling Facility Performance: A Real World Perspective

(Originally posted 2006-02-24.) My friend Frank Kyne in the ITSC Poughkeepsie center sent me a link to this draft RedPaper. It provides useful information, from some realistic benchmarks, on a number of Coupling Facility configuration options. I haven’t exactly been idle in this space recently: One of my favourite clients has sent me their DB2Continue reading “Useful RedPaper: Coupling Facility Performance: A Real World Perspective”

Undocumented Catalog Address Space Command – CATSTATS

(Originally posted 2006-02-22.) APAR OA15323 documents the F CATALOG,REPORT,CATSTATS and F CATALOG,RESET,CATSTATS commands which became available with z/OS Release 7. The REPORT command will list I/O access statistics, as well as BUFNI, BUFND, and STRNO information for each catalog. To limit the command to just a single catalog there is a second format (using theContinue reading “Undocumented Catalog Address Space Command – CATSTATS”