Author Archives: Martin Packer

(Originally posted 2005-06-29.) As a relative newcomer to the world of web programming I’ve been learning javascript. The reason I chose this language is (quite apart from already knowing java/swing) there is a very useful javascript tool called GreaseMonkey. Greasemonkey allows you to modify web pages you’re browsing. Such modifications include Inserting HTML into aContinue reading “GreaseMonkey”

(Originally posted 2005-06-15.) Yesterday we IBM “pioneer” bloggers had a conference call where we thought about enhancements to this blogging site. One that seemed to get some measure of support was the notion of a place where readers could make unsolicited comments and ask questions. I’m just writing about things I think are interesting. I’mContinue reading “Things I could write about”

(Originally posted 2005-06-13.) For a number of years now we’ve been talking about the importance of DB2 Virtual Storage management. The real credit goes to John Campbell of the DB2 lab who pioneered this stuff. We usually see DB2 Virtual Storage as an issue in 2 ways: A client presents with the problem and asksContinue reading “DB2 Virtual Storage Goes Mainstream”

(Originally posted 2005-06-13.) I’d made the assumption (in my code) that IRD would vary offline the top logical engines when it decided to vary an LPAR’s logical engine offline. In fact that isn’t the case. I have data from a US company where it’s engines 2 and 3 (out of the range 0-11) that tendContinue reading “Learn from my mistakes – Which Engines Does IRD Vary Offline?”

(Originally posted 2005-05-25.) This is mostly to say a big thank you to all the customers and other consultants at UKCMG (which has just ended). It’s great to catch up with you all. And also to spend time with Don Deese and Mike Moroz. > I genuinely believe in user groups and so I’d likeContinue reading “UKCMG Conference”

(Originally posted 2005-05-09.) Here’s another breakage of Accounting Trace that’s been fixed: APAR PK03905 describes a problem with DB2 Parallel Task Rollup that causes the Group Buffer Pool Accounting data for GBP 0 to be missing. (Its title talks about IFCID 148 but in the detail IFCID 3 is roped in. IFCID 3 means “AccountingContinue reading “DB2 Accounting Trace Parallel Task Rollup – A Problem Child?”

(Originally posted 2005-05-04.) APAR PK04803 describes a problem with RRS attaches: The value in qwacejst may be zero or less than the one in qwacbjst for rrsaf threads that execute in multiple task. This could involve records with qwacrinv equal to 6 and/or 16. The fix for this one isn’t due until July.

(Originally posted 2005-05-04.) I just saw the following APAR close. PQ99525 fixes a couple of problems for “nested” DB2 access i.e stored procedures, triggers and user-defined functions (UDFs). For anyone thinking “this is not my shop” I think you should consider that these functions are appearing in many modern applications and your Applications people probablyContinue reading “Of interest to performance people in DB2 Stored Procedures environments”

(Originally posted 2005-05-03.) My thanks to Greg Dyck for pointing out the following on IBM-MAIN: “The Store-CPU-Identifier now allows for a 8 bit partition identifier but the ESCON I/O protocols only allow for a 4 bit identifier. This is the reason that multiple channel subsystems must be implemented if you want more than 15 partitionsContinue reading “ESCON vs FICON and LPAR IDs”

(Originally posted 2005-04-28.) I’m reminded by a question on MXG-L Listserver that many people don’t understand how LLA works – and in particular how to interpret the statistics in VLF’s SMF 41 Subtype 3 record. You really have to understand the exploiter to make sense of the statistics. Here’s how it applies to LLA… LLAContinue reading “LLA and Measuring its use of VLF”