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All posts
Another Great Blog - Eightbar
If you have any interest in novel, webby or metaverse things you'll like the Hursley Eightbar blog .
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Gameframes Post Updated
I updated my April 2007 Gameframe post . I'm not sure if the mechanism you're using to follow my blog will've alerted you to this. Nothing desperately fundamental but it has been almost 7 months.
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My Favourite Wikipedia Page
My Favourite Wikipedia Page: List of fractals by Hausdorff dimension
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Peggy Zagelow's Blog
I'm very pleased to note Peggy also has a developerWorks blog. She's one of the leading lights in DB2 Development. Her blog is here
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Memories of Batch LSR
Another trip down memory lane - prompted by the thread on IBM-MAIN of Batch LSR vs Hiperbatch. Batch LSR started out as a prototype by Paul Dorn of the IBM Washington Systems Center. He was contributing to a book on writing a subsystem but also trying to solve a problem with Batch VSAM tuning. So Batch LSR started out as an example of a subsystem. (I don't recall a rash of subsystems written by... [More]
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DYNDISP and DDF?
To whoever it is in Denmark that's repeatedly hitting my blog today with a search for "dyndisp" and "ddf" I'd love to know what it is that is causing you to search for those two terms together. As you're on my (day job) patch perhaps I should be talking to you directly. So feel free to contact me by clicking on this link . (I'm hoping the "mailto:" URL form works on your system.) And, yes, I am... [More]
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z/OS R.9 RMF Parallel Sysplex New Fields
I've just re-read the XCF (74-2) and CF (74-4) sections of the z/OS Release 9 SMF Manual. There are some nice things in there... XCF (74-2) Number of buffer 1KB blocks by path (R742PUSE). This should tell you whether memory waste by over-specifying CLASSLEN is a problem. And some of the other scenarios. Member job name (R742MJOB). I'd like to believe this would tell us which IRLM a given member... [More]
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Memories of Hiperbatch
It's nice to see a flurry of activity in IBM-MAIN about Hiperbatch. And it's more for the emotional reason of reminiscence than for any stunning insights that I'm blogging about it... Back in 1988 I ran a technical project in my then customer, Lloyds Bank, to evaluate Data In Memory (DIM). It was a fun project with a wide range of workloads on multiple machines, including the then-new DB2. So we... [More]
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WLM-Managed DB2 Stored Procedure Address Spaces
I was contacted by the team updating the SG24-7083 "DB2 Stored Procedures: Through The Call And Beyond" this past week. Their question was quite straightforward: "One of the statements in the book, in the chapter on WLM address space management states: To help analyze the use of resources by different types of stored procedures, you should name the server address spaces in such a way that it is... [More]
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GSE Conference 2007
Last week I attended GSE Conference for the first time in a long while. And I'm very glad I did. I very much enjoyed presenting Memory Matters in 2008 . If you've seen me present it before you might notice some minor tweakings. We learn as we go, don't we. :-) As usual the challenge is "too much material". I attended a number of other presentations. For me the highlights were: Fabio Massimo... [More]
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Hackday4 and Referer URLs
I'm going to have to stop adding "(sic)" after every use of the word "Referer". As in "Referer URL". The term itself comes from one of the standard HTTP headers. And therefore is somewhat fixed. Despite giving my "wetware spell checker" a pink fit on a frequent basis. :-) Anyhow, in this blog entry I talked about how I can - as standard - get a display of the URLs people come from to land on my... [More]
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More on Coupling Facility Async / Sync Thresholds
Following on from Coupling Facility Async / Sync Thresholds - They Are A'Changin' I've been informed by Development there is a new improved write up on how the Dynamic Sync/Async conversion works in Chapter 6 of the z/OS Release 9: Setting Up A Sysplex manual. I've read it and it is VERY good. One thing to pull out is that there isn't just one threshold... There are different thresholds for Lock... [More]
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Coupling Facility Async / Sync Thresholds - They Are A'Changin'
APAR OA21635 is one of a rare breed: A change to the thresholds for z/OS's automatic CF Request conversion. (I'm told this has only happened once before.) If you recall z/OS Release 2 (in 2001) introduced a very nice function that automatically converts Coupling Facility requests from Sync to Async, based on thresholds. The purpose of this is to minimise the CPU cost for a coupled z/OS system,... [More]
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The "Gas Gauge" was indeed more than a gimmick
Back in April this blog entry incorporated a picture of the z9 HMC display that includes the "gas gauge" (or "power meter" if you prefer). This press release details a rather more serious purpose for the thing. And thanks to John McKown for pointing out the press release in IBM-MAIN Listserver.
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New Support for BatchPipes/MVS
As many of you know I've been very fond of BatchPipes/MVS (aka "Pipes") down the years (17 to be precise). So I'm pleased to see APAR PK34251: ADDING BATCHPIPES SUBSYS SUPPORT TO TEMPLATE UTILITY describes some new support in the DB2 Load Utility (as driven by the Template utility) which makes it much easier to use with BatchPipes/MVS. (For reference here's the BatchPipes For OS/390 Version 2... [More]
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DB2 Version 9 - STATIME Default Decreased to 5
I'm in a session where we're going through DB2 Version 9 migration considerations - and right now there's a table on display with changes to DSNZPARM defaults. One of real value is that STATIME has changed to 5 minutes from 30. Unless you've overridden it you should now get much better information at the DB2 subsystem level. This does, of course, mean 12 sets of Statistics Trace records an hour,... [More]
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DB2 Version 9 RLF - Not Just For SAP
Namik Hrle, the IBM Distinguished Engineer for DB2 for SAP, presented yesterday to an internal audience. (It's the first time I'd seen him present and he's a very dynamic presenter.) His presentation prompted me to download the Enhancing SAP by Using DB2 9 for z/OS Red Book . One item I'd like to pull out is the enhancements in DB2 Version 9 to RLF . RLF will cancel SQL execution for an... [More]
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Technorati
I'm now playing with Technorati: Technorati Profile .
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I May Not Know Who You Are But I Have Some Idea Why You're Here
I don't think you can see this information but I can see what are called "Referrer URLs" for hits on this blog. (The HTTP protocol defines a header that contains the URL you came from - when you clicked on a link.) Disregarding the several "Direct" hits - which tell me nothing - I see lots of referrer URLs with some information in them, such as: Google, Yahoo etc searches. Other blogs.... [More]
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Bye Bye Internet Explorer
Finally the last web application I use that required Internet Explorer is replaced with a Firefox-friendly version (or so we've been told). Hurrah! Except, as always, I'll believe that when I see it. (This is our Online Travel Reservations application that used an ActiveX control. Now it looks very much like an Eclipse application, except I'm certain that's just a styling thing.) And so I start to... [More]
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Is UCB Too Obscure For Wikipedia?
Well, is it? Apparently there are umpteen (count'em if you want a more precise number) :-) expansions of the acronym "UCB". But the one I care most about is Unit Control Block. (I think had been born before this meaning came into being - but I'm not sure.) :-) Actually Unit Control Block was not one of the listed meanings. So I added it yesterday - but didn't write much on it. You're probably... [More]
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Late To The Party
I'm towards the end of revamping our analysis code to support (z9) and z/OS R.8. What took us so long? :-) I'm telling you this for two reasons: So you know what there is that might slow you down. So you have some view as to whether we can competently process your data. :-) System z9 About the only change in instrumentation between z990 and z9 is the separation of specialty engines into pools. But... [More]
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Mor(e )on UIC
Thanks to the people who responded to this blog entry . And to the people who talked to me offline. The result is a slight shift in emphasis: I never did talk about UIC as the primary metric of memory constraint. If you read the referenced blog item I mentioned it as one of three, alongside paging rate and free frames. The shift is that I'm going to be more strident about UIC in future, relegating... [More]
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Memory Metrics Now That z/OS Release 8 Is Upon Us
I was asked an interesting question today by a customer - one with dozens of LPARs and therefore not much time to study each one in excruciating detail... "Given that System High UIC (hereafter referred to as 'UIC') behaves differently in z/OS R.8 how should I treat it?" I've posted on this question in MXG-L Listserver, soliciting experiences and opinions. With z/OS R.8 we replaced the "page-UIC"... [More]
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System z Technical Conference, San Antonio TX
Last week I was at the System z Tech Conference (again getting my zeds mixed up with my zees). :-) I presented 4 times, one of which was a repeat. What's especially nice is that I got 87 attendees for the "Memory Matters in 2008" presentation - spread across 2 sessions. This was despite the second time being the very last session of the conference... and 22 people still showed up to that! So... [More]
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SCRT Version 14.1.0 is Announced
I previously mentioned the change in zNALC LPAR setup... You can (with APAR OA20314) now specify LICENCE=ZNALC. The SCRT co-requisite is Version 14.1.0. By the way, from when you submit your SCRT report at the beginning of August you have to use this new version (until a new one is mandated) in order to be eligible for Sub-Capacity Pricing. There are a number of other changes, some of which are... [More]
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z/OS Performance Instrumentation Management Techniques wiki
I've just created a wiki to discuss primarily SMF. Mainly from the management perspective, rather than the contents of each individual record. This follows on from things I've mentioned in this blog before. If you'd like to contribute to it (and it is DESPERATELY in need of contributions right now) get a developerWorks screenname and send it to me here . Then I'll enable you to edit the wiki. You... [More]
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Why Mainframe Folk Should Care About Web 2.0
I presented a set of (someone else's) foils on Web 2.0 to my team meeting last week. (Interestingly, being 6 months old they were already way out of date - what with Twitter and all.) Remember I'm in a mainframe crowd of effectively "gurus". :-) So why should they be interested in new-fangled webby stuff? So I got to thinking... Dear reader, why should you care about Web 2.0? The minimal answer is... [More]
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Feedback from my UKCMG Mainframe Performance Instrumentation Birds Of A Feather
It was a very good session, even if it was attended by just a "hard core" of mainframe sites. I think everyone said at least something and several said rather more than that. Here are some things I'd like to note from it... There was a general feeling that it'd be useful to have a name for a machine that could be entered on the HMC and flow through to SMF records, particularly Type 70 (CPU). So... [More]
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Abstracts for System z Technical Conference, San Antonio, September 17-21
Here are my abstracts for the conference: Session B11: DB2 Data Sharing Performance for Beginners This presentation provides an introductory-level view of how to look at the DB2 Data Sharing performance numbersfrom both a z/OS / RMF and a DB2 perspective. Performance topics include: XCF, Coupling Facility, Data Sharing Structures, The application's perspective, and Structure Duplexing..... [More]
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And Something Else That Confuses Me
This customer is using DB2 Hiperpools, despite being on a z9 BC processor and running DB2 Version 7. What I notice from DB2 Statistics trace is that most of the Hiperpool pages are not backed by memory. In other words they've ceased to exist. This despite there being plenty of memory in the LPAR. One thing that's also significant is that there are very few reads back from the Hiperpools. It's... [More]
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It Doesn't Take Much To Confuse Me
... with a Performance Consultant? :-) Seriously, here's something that made me go "hmm"... I started looking at the latest set of data from a customer... Their biggest-CPU WLM workload is called "BATCH" when they told me they were a CICS shop - and that CICS was their main CPU consumer during the day. But it turns out that the biggest service class within that workload contains exclusively CICS... [More]
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IMS Version 10 Memory Enhancements
Regular readers would know I'm working on my "Memory Matters in 2008" presentation, which is a re-spin of the '07 Version. One of the things I talk about is IMS. Thanks to my team mate Andy Wilkinson for this list of IMS Version 10 enhancements, all of which are virtual storage usage improvements. Here are the more important items: OTMA message flood protection (prevents LSQA filling). This is... [More]
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UK GSE Conference 30-31 October - Memory Matters in 2008
One of the problems with having a presentation with a topical title is that you keep having to update the darned thing. :-) "Memory Matters in 2007" is a case in point. It's morphed over the years from two presentations: "Central Storage Performance" and "Expanded Storage Performance" (the latter of which eventually became obsolete) to a presentation that covered OS/390 real memory, DFSORT and DB2... [More]
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Humble Pie Regarding DFSORT and SMF
(Also posted to MXG-L Listserver (MXG-L@PEACH.EASE.LSOFT.COM) which I highly recommend as a place where mainframe performance people hang out.) I must confess I feel slightly foolish about this... :-) After having asked for input into my UKCMG BOF one of the themes that came out was better ways of doing what IFASMFDP does. (I already have this on my agenda - as you'll know if you follow my blog.)... [More]
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Madness At Passport Control
I happened to be travelling through Heathrow Terminal 2 yesterday and the day before. Two incidents that made me scratch my head, both related to Passport Control... On the way out there are two Passport Control desks, just past Security. They are set a few feet apart and people can go either side of either of them. For once there was someone on duty, but only one officer. At the head of the queue... [More]
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Birds Of A Feather Session at UKCMG Conference, June 25-27
As you probably know this year's UKCMG conferenece in June 25-27, Whittlebury Hall, Northants. I noticed when I read the agenda yesterday 2 things: Glenn Anderson's being worked awfully hard . He's a great speaker so do make the effort to attend his sessions. There's a BOF session on each evening - just before the entertainment. So I rang Laura at UKCMG up and offered to run a BOF. I got a "that's... [More]
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XCF Performance WSC White Paper
I'm reminded of this white paper on XCF Performance from Joan Kelley and Kathy Walsh. It's a good read and has been recently updated. It does also remind me that there are "D XCF" subcommands that give information that isn't in the RMF data (SMF 74 Subtype 2). We process these records in our consulting and I'm getting considerably more familiar the underlying data. (I also had a situation recently... [More]
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Big Green
Now I know why, as previously reported here, there's a new power meter on the HMC. See this blog entry and the links from it for more details of the "Big Green" energy efficiency initiative. And this goes way beyond the "packets of grass seed" campaign of last year - which highlighted the already available energy-saving characteristics of the mainframe.
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As Seen on Nürnberg U-Bahn
Here's a nice BSOD from a ticket machine on the Nürnberg U-Bahn. :-)
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When Good Work Doesn't Go To zIIP / zAAP Heaven
Whenever I talk about zIIPs and zAAPs I'm reminded of Zip Zap miniature radio-controlled cars . But (to get past the censors I have to say) zIIPs and zAAPs are not toys. Here's an extract from a post on MXG-L that Bernie Pierce made. (I reproduce it with his kind permission.) If there is contention for the local lock, the cross memory local lock, the CMS lock or any other suspend lock, units of... [More]
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DB2 Data Sharing Performance and Coupling Facility Enhancements for DB2 Version 8
Occasioned by some recent enhancements to MXG I thought it high time I talked about a couple of Coupling Facility commands that DB2 Version 8 can take advantage of: (And thanks to Barry Merrill for the MXG information and the sample data I'm using here.) MXG Version 25.04, May 7, 2007 provides support for these enhancements. Coupling Facility Level (CFLEVEL) 13 introduced the WARM and RFCOM... [More]
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Serious Work of Drinking in München
Thanks to Margaret Koppes of the European Patent Office for this picture of me and Glenn Anderson hard at work at the "main tent session" :-) in München:
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UKCMG Conference, June 25-27, Whittlebury Hall, Northants
I've just submitted my three presentations for this great conference: Much Ado About CPU Memory Matters in 2007 DB2 Data Sharing Performance For Beginners UKCMG is - for me - a great chance to catch up with customers, vendors and others in the industry. Its prime focus is Performance - multiplatform in fact - but we always have a thumpingly good showing of mainframe and DB2 topics. And this year... [More]
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Gameframes
Hmmm: IBM press release on the gameframe . I'd like to see a lot more detail on this before I go "whoopie!" but it does sound like an intriguing idea. It would be the first "specialty" engine to actually feature different hardware. Reminds of me of the 3090 Vector Facility but it's really nothing like it. And at this stage there's nothing about what will actually be shipped. Still, I'm happy to... [More]
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What I Learned From My Conference Evaluations
I was pleasantly surprised to see my conference evaluations so soon - given the European System z Technical Conference was only last week. Very professional to have the feedback straight away. All the people who filled in the evaluation forms - and that exceeded 50% of the attendees in every session - were very kind, I feel. Here's what I learned: I still talk too fast, and still have highly... [More]
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Lest We Forget - The legacy of Guernica
Here's a salutary item from the BBC: The legacy of Guernica .
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European System z Technical Conference - End of Day 5
Marna Walle: Recent Installation Enhancements and Directions Marna gave a very good presentation, covering a wide range of topics in this area. Here are some highlights - at least from MY perspective: In z/OS R.7: z/OS R.7 UNIX introduced Dynamic Service Activation for SELECTED corrective PTFs. Only works for PTFs marked as "for dynamic activation" with ++HOLD REASON(DYNACT). Not all PTFs are... [More]
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European System z Technical Conference - End of Day 4
Parwez Hamid: System z9 BC GA2 and System z9 EC GA3 Update Available from 11 May, Driver Level 67 provides the BC GA2 / EC GA3 enhancements. The current one is 63. Parwez set the expectation the upgrade can be done non-disruptively if you plan carefully. Common to BC and EC machines: LPAR Group Capacity Limit. Group of LPARs on one footprint need not be in the same parallel sysplex. Requires z/OS... [More]
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European System z Technical Conference - End of Day 3
Me: Memory Matters in 2007 I was pleased that about 60 people attended this presentation. Connie Beuselinck: System z9 OSA-Express2 Update and Performance Benchmarks Network Traffic Analyzer was announced today for QDIO problem determination. It's exclusive to z9 and OSA-Express2. QDIO Diagnostic Synchronisation (also announced today) allows z/OS to signal to OSA-Express2 to synchronise software... [More]
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SMF Dump Program - IFASMFDP
I just started talking to the original developer of the IFASMFDP SMF Dump Program about adding more record selection sophistication to it. I can promise absolutely nothing but are there any requirements any of you have for the SMF Dump Program?
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European System z Technical Conference - End of Day 2
Paul Rogers: z/OS Releases 8, 9 and Beyond This is very much an overview presentation. Other sessions go into more detail. Paul provided a salutary reminder that z/OS Release 6 goes out of service at the end of September. We're now supporting only the current release and the 2 previous ones. APAR OA20314 (in support of zNALC) allows you to IPL with LICENSE=ZNALC rather than hardcoding the LPAR's... [More]
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System z Tech Conference - End of Day 1
It's been really nice meeting with so many acquaintances. The highlight of Day 1 was undoubtedly Pat Artis presenting on HyperPAVs. As I have a couple of foils on HyperPAVs from the DB2 perspective on Thursday it's going to be nice not to have to explain them in too much detail - as Pat did such a great job.(The Thursday session is on I/O and DB2 Versions 8 and 9, a much wider ranging version of... [More]
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European System z Technical Conference Begins
The agenda this time is chock full of great sessions. I've "marked my card" for every single session . Bob Hoey - marketing guy though he is - is giving a keynote speech that fills one with a lot of hope for the mainframe. (Bob, if you know nothing else about him, participated in the infamous "IBM Mainframe Marketing" videos that appeared on You-Tube a few months ago.) So I'm really looking... [More]
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IBM System z Technical Conference 2007
This year's IBM System z Technical Conference is 16-20 April in Munich. Now I've got my three presentations together I can relax and have just perused the agenda: There are some very good sessions and some excellent speakers. My sessions are: Much Ado About CPU I've worked pretty hard to move the z9 stuff into the main flow and also added stuff on z/OS R.8 and a tiny bit on R.9. I think it's... [More]
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How the WebOS Evolves?
Here's a nice picture from the Minding the Planet blog :
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An Excellent Paper on Uniprocessor Performance Management
My good friend Linda August (of the IBM Washington Systems Center and previously of the global Performance Management team I was a member of) has written a very good paper (and an accompanying presentation she gave at SHARE in February). The theme is highly topical: The management of uniprocessor LPARs. Topical because of the increased uniprocessor speed of the z990 and particularly the z9... [More]
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John Backus RIP
I guess I must be part of the "ungrateful peasant" generation of computer geeks... I never really liked FORTRAN. And now John Backus who led the team that developed it is dead . For me the elegance of other languages biased my view - but that's to miss the point: FORTRAN preceded them. And with all such pioneers elegance of form is often lacking. I did have some practical acquaintance with... [More]
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Scratch - A Great Way To Teach Children Programming
Some time ago a colleague pointed Scratch out to me. It's a programming environment for children. When I was a kid I kind of learnt programming from the Elsevier Monographs my Dad had on his bookshelf. He (who's probably going to read this) gave them to me for safekeeping some time ago. So I count HIM as my first bad influence. :-) But he did insist on STRUCTURED programming, so maybe he's a GOOD... [More]
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Not Just People Twittering - Vehicles As Well
Here's an interesting BBC News Article: Vehicle warning system trialled . So let me see now, when we said the fridge would talk to the microwave - as everything would have an IP address - did we really envisage that they would Twitter? :-) Can you imagine "The Bloggings of an uncleaned fridge?" :-) And can you imagine what'd happen if my fridge started Twittering and next door's microwave yakked... [More]
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Twittering and Blogging
Here's a useful contribution to the debate about Twitter: From a friend's blog . There's much mileage in the comments - which is where the action really hots up. :-) Actually her blog is in general a good read - but maybe I'm biased as she's a friend of mine. She's a Web 2.0 enthusiast with a great line in photos and original art. (If you want a business justification for reading her blog she's a... [More]
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DB2 9 Memory Requirements
Twice the "128GB" question has come up in newsgroups (the latest in DB2-L). This sort of thing freaks people out - so let me tell you what I know of the matter... I was fortunate to attend the T3 for DB2 9 in February. This question came up in the context of some changes to DDF : In Version 8 communication between DDF's DIST address space and the DBM1 address space was via CSA (actually ECSA so... [More]
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Famous Names on Twitter - And Is It Going To Change The Face Of Politics?
On Twitter I once followed Steve Wozniak - but it turned out not to be him. :-( Now I'm following John Edwards (and it really does appear to be him). See his Twitter page . I say "it does appear to be him" because the twitterings seem to support that conclusion, plus there is a photograph of him (not that that's strong evidence). (The ones for the supposed Steve Wozniak never gave credence - it... [More]
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3G Card and Sufficient Rurality
I'm writing this in the back of a taxi - on my way to Heathrow. (A 3G card for my Thinkpad was waiting for me when I got home yesterday.) My conclusion is that we live somewhere "sufficiently rural" as I've lost signal once . (That was between us and Henley.) Any more than that and I'd think we lived in the sticks. As it is to actually lose the signal at all is a reassurance that we don't live... [More]
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Twitter - twittering on? Or real insight
Whichever it is, here's my Twitter badge. Feel free to befriend. :-) follow martinpacker at http://twitter.com
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Wikipedia
Whatever one's feelings about the definitiveness of Wikipedia a lot of people find themselves there, looking for information. Having twice anonymously edited articles - in one case to correct an error, in the other to add a minor snippet - I finally succumbed to the urge to get an ID. So my efforts aren't quite so anonymous - and are therefore a bit more accountable. I'm not going to go overboard... [More]
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DB2 9 and End Of Service For DB2 Version 7
Willie Favero is also blogging about this - and I stole the link from him... Here's the End of Service announcement for DB2 Version 7 . It goes out of service on June 30, 2008. I've just sat through four days of the T3 class for DB2 9 for z/OS - in Silicon Valley Lab. My "take home" message is that there's lots of stuff in all the usual areas. It's a truly exciting release. Note: It's "DB2 9" and... [More]
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z/OS Release 9 is Previewed
See the z/OS Release 9 preview statement if you're interested in z/OS. There are lots of interesting Performance items previewed, as well as other line items. It's expected to become available in September 2007, following the current pattern of a new release each year (preview in the so-called Spring :-)and release in the Autumn) so expect lots more information on it later this year. I do wonder... [More]
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z/OS Release 8 Real Storage Changes
I suggested (in z/OS Release 8 Real Storage Manager SMF Record Changes ) that I might talk about the changes to RSM in z/OS Release 8. As the release has been out now for about 4 months some of you might actually be on the brink of putting it into production. :-) Seriously, you probably are planning for the day when someone cuts over to Release 8. RSM was largely rewritten - for a very good... [More]
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Going The Distance
I presented to the Large Systems GSE meeting in Dudley on Wednesday on "DB2 Data Sharing Performance For Beginners" and an interesting question came up... "At what distance does performance begin to suffer when moving machines in a parallel sysplex apart?" As it happens I am dealing with exactly that question in a customer right now. It seems it's a popular thing to attempt. (I know: One user... [More]
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z/OS Release 8 CPU SMF Record Changes
I've just been looking at some fascinating SMF 70 records. They come from a System z9 EC S54 machine and the LPAR they're from is running z/OS Release 8. I say "fascinating" because: I've not seen an S54's data before. (This is the largest z9 machine - with all 4 processor books fully populated with engines.) There are changes that I asked RMF (and PR/SM) Development to add into Release 8 that I'm... [More]
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z/OS Release 8 Real Storage Manager SMF Record Changes
In z/OS Release 8 Real Storage Manager (RSM) implemented brand new algorithms. One of the more significant changes was the adoption of a "new style" UIC value. This behaves much more like the old Expanded Storage Migration Age. Accordingly the old UIC value (SMF71ACA) isn't really appropriate to use anymore. Or at least it won't behave the way it used to. And before I go any further the SMF Type... [More]
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CICS and SecondLife
In Mainframe v-Business Boas Betzler threw out a challenge: "Demonstrate SecondLife talking to CICS". I've picked this up on behalf of IBM. Now, why on earth would you want to do that, Martin? To get beyond the "because it's fun" answer (which is also true) let me tell you my view on SecondLife... First, it is NOT a game. Emphatically not. Though it is a lot of fun. By way of analogy consider the... [More]
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Better Late Then Never - RMPTTOM
Well, I don't know about that. Maybe this contribution to the debate won't add much. But there must be at least one performance person out there who hasn't heard of the discussion around RMPTTOM. But would I want such a person amongst my readership? :-) I'm not going to rehearse the whole story. It is pretty well understood that the old default was creaking somewhat.What I am pleased by is the way... [More]
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2 More DB2 Access Path APARS
Here are a couple more SQL processing APARs. APAR PK22814 for Version 8 ESTIMATED SUBQUERY COST IS TOO HIGH WITH SORT MERGE JOIN. The APAR text says Correlated subquery cost is over-estimated for sort merge join. A well-performing sort merge join plan might not be chosen by DB2. Correlated subquery cost can be overestimated for sort merge join. This may cause a sort merge join plan that performs... [More]
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DB2 Virtual Storage - The Journey Continues
DB2 Version 8 introduced some very significant exploitation of 64-bit virtual storage. It would be naive to believe that was a total conversion to 64-bit and indeed installations' mileage varies, depending on circumstances. Here are two APARs that show the journey continues... PK21268 MOVE CURRENT PATH STORAGE OUT OF STACK AND INTO ABOVE BAR From the APAR Comments: The working storage to hold... [More]
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ASCII to EBCDIC Conversion with DFSORT
( Scroll down if you're not interested in DB2 ) This past week I've been updating our SQL Analysis code to cope with Unicode SQL statements. (If you bind a package or plan once you've gone to DB2 Version 8 New Function Mode the statement text is stored in the Catalog in Unicode.) These statements are in Unicode UTF-8 which is extremely similar to ASCII. So I snaffled some existing code of mine... [More]
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Unknown Unknowns
Nope, I'm not going to do a Rumsfeld. :-) But there are a couple of things I didn't know (I didn't know) about DFSORT. Relating them to you is probably OK because It's not something I'm embarrassed about.:-) If you want to understand some of the funkier new DFSORT tricks you probably need to know these things. Consider these DFSORT examples (which I take no credit for). They are used to deal with... [More]
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From the "Made Me Chuckle Anyway" Department...
Saw an APAR described as INCORRECT OUPUT :-) the other day. That reminds me of a time long ago when a friend had a foil titled Qualtiy .:-)
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Parsing XML with DFSORT
Following on from Generating XML Using DFSORT - Part II here are some thoughts on how to parse XML with DFSORT. NOTE: For more complex XML than this entry describes you probably want to use the XML Toolkit for z/OS . This provides C++ and Java parsers for XML and a stand-alone XSLT processor. In this example I'll show you how to take XML that looks like this and create a flat file from it:... [More]
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Generating XML Using DFSORT - Part II
In Generating XML Using DFSORT - Part I I described how to generate XML using some of DFSORT's new features. But the XML we generated was only one of the possible styles of XML: Most of the information was specified as attributes (with the values enclosed in quotes). Here's a sample line: <member surname="Mercury" firstname="Freddie" job="Singer" /> In this case the attribute job has the... [More]
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Generating XML Using DFSORT - Part I
Following on from This entry on creating CSV files here's the first of several entries on manipulating XML with DFSORT... This is not intended to be a tutorial on XML but rather an exploration of how DFSORT can read (shred) and write (compose) XML. (I also use the terms ingest and emit synonymously.) Hopefully some of the basic concepts of XML will come across during the course of these blog... [More]
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Using DFSORT to create CSV files
I plan on writing some entries on creating and parsing XML with DFSORT (using the UK90006 / UK90007 functional enhancments that DFSORT Development recently announced). But here's a limbering up example - creating a CSV file from regular sequential file input. CSV files ( C omma- S eparated V alue (or V ariable if you prefer)) are of the form "JDLFJDJ DF",4146,"FKJFK" "JDJDJ JKJJ",12352,"EE... [More]
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Search and Replace with the new DFSORT functional PTFs
Here's my first tip with the new UK90006 / UK90007 DFSORT PTFs. It's an apparently minor enhancement that I think people will like... It leads to a more elegant syntactical expression. It is more maintainable - in the face of changing record layouts. Suppose you want to search a file for a string in a particular position in each record and replace all matching instances with a different string. (... [More]
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DFSORT New Function PTFs
As many of you know I like to beta DFSORT function PTFs. About once a year a new set of functions appears, many in direct response to customer requirements. Occasionally some of the enhancements are at my suggestion. :-) Yesterday PTFs UK90006 and UK90007 became available. (Being UK based it's nice to see PTF numbers beginning with UK but I read no significance into this.) :-) You can read the... [More]
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My New Job
As of today I have a new job. I still work for IBM. I'm still UK based. I still do performance analysis with customers in the same way. But some things have changed: I now work in Software Group, rather than what's now called Global Technology Services . I now have a geographical territory that stretches from Rejkavik to Vladivostok, and from Stavanger to Cape Town. I would quite like to visit all... [More]
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DB2 Data Sharing Performance for Beginners
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 next year. Would this be of general interest? When I say For Beginners I'm not entirely sure I mean that. :-)... [More]
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Another MIDAWs APAR - Might Improve Its Performance
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 the CCWs (Channel Command Words)... (M)IDAWs point at the data for the I/O and CCWs point at... [More]
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More REORG Utility Flexibility
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 either large in-memory sorts or multiple parallel sorts. But sometimes you don't. APAR PK18059 for V8... [More]
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Some SQL Access Path Improvements
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 OR COL=LIT EXISTS ON SMJ KEY PK20229 POOR QUERY PERFORMANCE WHEN FETCH FIRST 1 ROW AND INDEX... [More]
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DDF Row Counts Bug
One of the themes for Distributed access to DB2 that I talk about is Network Flows Optimisation , in particular ensuring that DB2 is taking advantage of such things as blocking... When DB2 sends rows back to a DDF caller it can block them or return them singly (and indeed the degree of blocking can vary). Appropriate levels of blocking can reduce network traffic, optimising the bandwidth and... [More]
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DB2 As A Web Services Provider
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 what the installation is trying to do with DB2. Often it's not the common or garden... [More]
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Lotus Sametime 7.5 Alpha 2
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, I am favourably impressed with 7.5, particularly as it's based on an... [More]
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Useful RedPaper: Coupling Facility Performance: A Real World Perspective
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 DB2 and RMF data for their production plexes. I won't comment on my observations (at... [More]
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Bad Access Path For FETCH FIRST n ROWS or OPTIMISE FOR n ROWS
APAR PK18018 documents a condition where the use of either the FETCH FIRST n ROWS or OPTIMISE FOR n ROWS clauses leads to a suboptimal access path. Occasionally you can get an ABEND. This APAR is marked for DB2 Version 8 only.
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Undocumented Catalog Address Space Command - CATSTATS
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 the catalog name) which will list only the catalog specified. The... [More]
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SMSVSAM / RLS Performance Fix
APAR OA14572 documents a problem where there is excessive SRB time and an increase in EXCPs for the index component of a VSAM KSDS accessed by RLS when two or more RPLs are adding records to the end of the data set.
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Enhancement For Users of DB2 EXPLAIN
APAR PK15454 documents an extension to DB2's EXPLAIN function which makes correlation of the various tables involved much easier. This enhancement is used by Visual Explain but can also be used by people querying the tables EXPLAIN produces, in particular DSN_FILTER_TABLE and DSN_PREDICAT_TABLE. When you EXPLAIN a statement it produces rows in the well-known PLAN_TABLE table, but also in these... [More]
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SQL Access Path Enhancement - Second of the day
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 the day... Take the case of a query like SELECT T1.* FROM SYSADM.TP1 T1, SYSADM.TP2 T2 WHERE T1.C2 = T2.C2 AND T2.C1 where T2.C1 is the... [More]
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Omegamon support for DS8000 Devices
APAR OA14839 documents Omegamon support for 2107 (DS8000) devices.
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