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All posts
Proposed "DB2 Through My Eyes" Presentation
I have a new conference presentation in mind.
Its working title is “DB2 Through My Eyes”.
Here’s the structure I’ve devised for it: Abstract What Is DB2? CPU
General Purpose zIIP Memory
Real Virtual I/O
Database Subsystem Application
Connections Performance Parallel Sysplex
Coupling Facility XCF Specialist Subjects
Restarts Workload Manager Stored... [More]
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Some WLM Questions
As I’m working with a couple of colleagues on a performance study I thought I’d list some “starter set” questions I’d ask about any customer’s WLM policy. [1] Before you go too far with this post you might like to read
Analysing A WLM Policy - Part 1 and
Analysing A WLM Policy - Part 2 but I don’t think I’m repeating myself much here. So here are... [More]
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I'm Surprised Nobody's Complained :-)
It’s a little surprising to me that nobody complained about one aspect of the behaviour in the code in
GreaseMonkey Script To Sum Selected Numbers In A Web Page .
I’ve been muttering under my breath and I wrote the code. This code naively assumes that in every web page there is just one body element.
It is rather naive, and I’ve known that for a long time. What really... [More]
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GreaseMonkey Script To Sum Selected Numbers In A Web Page
This post is meant to inspire people who like programming the web to do simple tasks.
It contains a sample Firefox GreaseMonkey [1] script, which I hope you will find useful. [2] Suppose you are looking at a web page, perhaps one with a table in, and you want to add up some numbers you see there.
Perhaps they’re in a column in that table. With this script you select the numbers... [More]
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How I Look At Virtual Storage
I thought I’d write about how I begin looking at virtual storage, occasioned by a customer who had a 24-bit virtual storage (878–10) ABEND [1] .
Most of this is in our code, so easy for me to do.
I hope you’ll find it similarly easy. You’ve had hints of this in
How Many Eggs In Which Baskets? and
Broker And SMF 30 . The game is really to use product-neutral... [More]
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The Effect Of CF Structure Distance
Here's an interesting case that illustrates the effect of distance between a z/OS image and a Coupling Facility structure. I don't think this will embarrass the customer;
It's not untypical of what I see.
If anything I'm the one that should be slightly embarrassed, as you'll see... A customer has two machines, 3 kilometers apart, with an ICF in each machine and Parallel Sysplex members in each... [More]
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Coupling Facility Memory
Or “who made all the pies”? I’ve written a number of times about Coupling Facility Performance but I don’t think I’ve written about memory for a while. In any case I’d like to share with you a couple of graphs I’ve taught my code to make. The first isn’t strictly speaking specific to Coupling Facilities. But it’s useful anyway and does help... [More]
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After An Indecent Interval
In After A Decent Interval I talked about the need for frequently-cut SMF Interval records.
This post is about bad behaviours (or maybe not so bad, depending on your point of view). It’s actually an exploration of when interval-related records get cut, which turned into a bit of a “Think Friday” experiment.
But I think - quite apart from the interest - it has some usefulness in... [More]
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What's The Point Of WLM?
At UK GSE Annual Conference I presented on DB2 and Workload Manager.
It occurred to me that one of the slides was a good basis for a blog post, posing the question “what’s the point of WLM?”
And this was the slide, with me “for scale purposes”. (Thanks to Karen Wilkins for the photograph.) So let me try to give you a synopsis of my view, expanding on each of the... [More]
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Not So Much Renaissance Man More Tool-Using Ape :-)
If you come to my blog only for Performance- or SMF-related topics you’re going to be disappointed in this post.
But if, like me, you’re interested in storytelling and web-related technologies then read on. This post is about HTML5 Canvas - a technology I really like. Some Of Why I Care About Web Technologies To try and keep this focused I’m going to talk only about why web... [More]
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The End Is Nigh For CICS
… and other address spaces, too. In Once Upon A Restart I talked about how to detect IPLs and restarts of CICS regions and MQ subsystems (and other long-running address spaces) - from SMF Type 30 Interval records. It’s easy to see starts but what about stops ? [1] It turns out you can estimate when address spaces stop from the SMF 30 Interval records (Subtypes 2 and 3): When there is... [More]
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Curiouser And Curiouser, Spike
As you’ve probably gathered I like to get nosy about how customers run systems.
This is probably best and most recently exemplified by this blog post:
Once Upon A Restart So this post is about another piece of curiosity:
What spikes can tell us about how people run systems.
In a way it’s similar to what restarts tell us, hence the above blog post link. I like “Think... [More]
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WLM Velocity - Another Fine Rhetorical Device I've Gotten Myself Into
Back in 2010 I wrote about a graph I’d developed for understanding how a Service Class Period’s velocity behaves. That post is here: WLM Velocity - “Rhetorical Devices Are Us” . At the time I was concerned not to show up the customer by displaying the graph. I think that was the right decision. But in the presentation I mention here: Workload Manager And DB2 Presentation... [More]
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DFSORT JOINKEYS Instrumentation - A Practical Example
Some technologies show up “in the field” very soon after they’re announced and shipped. Others take a little longer. Back in 2009 [1] I blogged about one technology - DFSORT JOINKEYS. For this post to make much sense you’ll probably want to read that post first. Here it is: DFSORT Does JOIN . Dave Betten and I have - at last - a set of data from a customer where one of the... [More]
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Workload Manager And DB2 Presentation Abstract
I’m pleased to be presenting three sessions at UK GSE Annual Conference, Tuesday 4th and Wednesday 5th November in Whittlebury Hall. Two are on the zCMPA (Performance and Capacity or “UKCMG”) track: Life and Times of an Address Space (Tuesday) zIIP Capacity Planning (Wednesday) I’ve written about these extensively.
Obviously they’re evolved a bit and I have specific... [More]
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