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Friday Philosophy – Dyslexia Defence League August 19, 2011

Posted by mwidlake in Friday Philosophy, Perceptions, Private Life.
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2 comments

NB This post has nothing to do with Oracle or even technology really. It’s just some thoughts about one aspect of my life.

I know I’ve mentioned this once before, though it was in an early blog post when I had a readership of about 8, but I am mildly dyslexic. If you want to know how I found out I was dyslexic then check out the original post. I’m quite fond of that post, as a non-technical one, though almost no one read it.

The thing is, I now cringe slightly when I say I am Dyslexic. I’ve sat on this post for weeks, wondering if I should post it. You see, it seems to me that dyslexia, along with some other oddities of perception, have over the last few years almost become a thing to be proud of. A banner to wave to show how great you are. “Hey, look at me, I am this good even though I have Dyslexia” or even “I am great because I have dyslexia”. Maybe I am just a little sensitive about it but it seems to me that more and more people make a thing about it. If I am being candid, I feel a little proud that I did OK academically despite it {I should point out there is no proven link between dyslexia and IQ but in exams you get marked down for spelling and slow reading speed means it takes longer to, well, read stuff!} and in the past I have been very open about mentioning it. Hey, this is my second blog on dyslexia!

However, I’ve had it suggested to me in the past that I use it as a defense for being lazy – Can I prove I am dyslexic? Does it really impact me that much? Well, actually no I cannot prove it and has it impacted me? Not a great deal I guess as I can read pretty much anything {I did say it was mild. Scientific papers and anything with very long words can be a challenge, but isn’t that true of everyone?}. My reading speed is about 120,150 words a minute. Average is about 250wpm. My wife seems to read at about 500wpm :-)

Also, don’t get me wrong, I fully appreciate that looking at a challenge you have and taking the benefits from it that you can is a very healthy attitude. If I remember right it was Oliver Sacks in one of his books (“the man who mistook his wife for a hat” maybe) who describes a man with sever Tourette’s syndrome {which is more often all about physical ticks and uncontrolled motions rather than the famous “swearing” aspect of it} who could somehow take advantage of his physical manifestations in his jazz drumming. He could just make it flow for him. But when he took treatment to control the physical issues, his jazz drumming suffered. He really wanted the benefit of the drugs for day-to-day life but keep the Tourettes for jazz. So he took the drugs during the week and came off just before the weekends when he played. Neat.

Does Dyslexia help me? I think I am more of a diagrams and pictures person than a text person because of my dyslexia and I think I maybe look at things a little differently to most people at times – because of the differences in how I perceive. That can help me see things that maybe others have missed? Maybe an advantage. I’ll take that.

Also, in my case at least, dyslexia is not an issue for me comprehending or constructing written prose. I think I write some good stuff at times.

But I don’t want to be dyslexic. Frankly, it p122es me off.

I’ll give you an example. I did a blog post a few weeks back and it had some script examples in it. I had nearly finished it when I realised I had constantly spelt one word utterly wrong. The spell checker picked it up. But just before I posted it, I realised I had also got my column aliases utterly wrong. I have a little set of rules for generating table and column aliases, it is not complex, but in my head the leading letters of a word are not always, well, the leading letters. I had to alter my scripts and then re-run them all as I knew if I tried to unpick the spelling mistakes manually I would mess it up, I’ve been there before. It took me hours. I can really do without wasting that time. {Update, since originally drafting this post the same situation with another technical post has occurred}. Then there is the embarrassment of doing something like spelling the name of a column wrong when you design and build a database. I did that in a V8 database when renaming columns was still not a simple task {was it really Oracle 9 release 2 before column rename was introduced?}. The database went live and accrued a lot of data before anyone made an issue of it. It then kept getting mentioned and I had to keep explaining.

I don’t see Dyslexia as a badge of honour and every time I see someone being proud of it (or to my odd mind it seems they are proud of it) or suggesting they are better than average for overcoming it (again, maybe it is just my perception), I just feel uncomfortable. I think all and everyone of us has something we have had to overcome to be “normal”.

Yet, on reading that above paragraph back, it is simply insulting to people who have fought and striven to overcome severe dyslexia or other issues with perception or communication. I certainly do not mean that (and I apologise unreservedly to anyone who is now fuming at me because of my callousness).

Maybe that is my issue with the whole topic – I am not uncomfortable with the notion of being proud to have overcome something like dyslexia and I admire people who cope with other conditions which make it harder for them to get by in our culture, but I just can’t see why you would be proud of the condition or want to use it as a bragging right.

I guess I want to be able to just acknowledge my dyslexia, point out it is no big deal in my case but it is why I spell like a 10 year old. It is as significant as the fact I’m scared of heights. I guess I cringe a little when I say it as I don’t want to be seen to be making excuses and I certainly do not feel, that in my case at least. I have won through against the odds. Maybe I’ve been a little hard-done-by occasionally but haven’t we all?

Friday Philosophy – Blogging Style and Aim August 12, 2011

Posted by mwidlake in Blogging, Friday Philosophy.
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13 comments

I’ve recently looked back at some of my earlier blog postings and also some notes I made at the time I started. I had a few aims at the start, pretty much in this order:

  • A place to put all those Oracle thoughts and ideas, for my own benefit
  • Somewhere to record stuff that I keep forgetting
  • I’d started commenting on other blogs and felt I was maybe too verbal on them
  • To increase my profile within the Oracle community
  • To share information, because I’m quite socialist in that respect
  • To learn more

It very quickly morphed into something slightly different though.

Firstly, it is not really somewhere that I record thoughts and ideas or where I record stuff that I forget. When I am busy, I sometimes only get half way to the bottom of resolving an issue or understanding some feature of Oracle. I tend to create little documents about them but I can lose track of them. I initially intended to put these on my blog. The thing is though, I don’t feel I can blog about them because I might be wrong or I raise more questions than I answer. I don’t think a public blog about technology is a good place to have half-baked ideas and I certainly don’t want people:

  1. reading and believing something that is wrong
  2. thinking I do not know what I am talking about
  3. seeing my rough notes as boy are they rough, often with naughty words in them and slang. Converting them to a familly-friendly format takes time. 

You see, there is the point about increasing my profile in the community. Part of me hates the conceit that you have to be seen as all-knowing or never wrong, as no one is all-knowing and never wrong. In fact, I think most of us find it hard to like people who put themselves as such.  But if I put out a blog saying “it works this way” and I am wrong or I simply say it in a clumsy way or I assume some vital prior knowledge, I could be making people’s lives harder not easier, so I spend a lot of effort testing and checking. It takes me a lot, lot longer to prepare a technical blog than I ever thought it would before I started. And yes, I accept I will still get it wrong sometimes.

Another consideration is that I make my living out of knowing a lot about Oracle. If I post a load of blogs saying something like “gosh I wish I understood how Oracle locks parts of the segment as it does an online table rebuild and handles the updates that happen during it”, then I obviously don’t know about that. Or I put out a post about how I currently think it works and I’m wrong. Tsch, I can’t be that good! How much should I have to think about how I am selling myself as a consultant? There is a difference between being liked and being perceived as good at what you do. If you want someone to design a VLDB for you, you probably don’t care if s/he is a nice person to spend an evening in the pub with - but you certainly care if they seem to be fundamentally wrong about oracle partitioning.

Balancing that, if you saw my recent post on Pickler Fetch you will see that I was wrong about a couple of things and there was some stuff I did not know yet. But I learnt about those wrong things and lack of knowledge, so I feel good about that. That was one of my original aims, to learn. Not only by having to check what I did but by people letting me know when I was wrong.

What about style? I can be quite flippant and, oh boy, can I go on and on. I know some people do not like this and, if you want a quick solution to an oracle problem, you probably do not want to wade through a load of side issues and little comments. You just want to see the commands, the syntax and how it works. Well, that is what the manuals are for and there a lot of very good web sites out there that are more like that. If you do not like my verbose style then, hey that’s absolutely fine.  But I like to write that way and so I shall.

So after over 2 years of blogging, I seem to have settled into a style and my aims have changed.

  • I try to be helpful and cover things in detail.
  • I try to polish what I present a lot, lot more than I do for my own internal notes. Maybe too much.
  • I’m going to write in a long-winded way that some people will not enjoy but it is my style.
  • I’m going to try and worry less about looking perfect as I am not.

I suppose what I could do is start a second, private blog with my half-baked stuff on it. But I just don’t think I’ve got the time :-)

 

 

 

 

I am Neo off the Matrix (apparently) March 30, 2011

Posted by mwidlake in AWR, performance.
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8 comments

I know I have mentioned it before, but I am a big fan of the OEM performance screens that are derived from the ASH/AWR information. One of the things I really like about it is the immediate information it gives you, in one glance, that things are “not normal”. Once you notice that things are not normal you can then, within a few seconds, get a feel for what is still probably OK and where you have something that has changed.

As an example of the immediate information, I recently came back to my desk and glanced at my OEM performance screen. It was showing the below:

This will not be an interesting picture to you, but to me it tells me a lot about my system

“data load has just ran” I said to my comrade-in-arms. “which one?” he asked. “The Delta – It ran the quick plan. But it started a bit late, 12:15. Oh, and looks like the transaction view code has swapped back to the full table scan plan and the summary code is not playing up at the moment.”

“you’re turning into Neo you are – can you see a lady in a red dress???” he asked.

That was of course a reference to the “Matrix” films where at times you see the virtual world displayed on a screen as a stream of characters running down the screen – but once you get used to it you can apparently “see” what is going.

The screen shot above is not even actually a very good example of what the performance screens can show you. One of my minor complaints about the performance screens is that it scales to show the greatest of the largest peak or a number of sessions to match the number of CPUs (real or fake) that are available to you. So if you have more CPU available than you need, you can’t see much detail in the graph. And if you have had a nasty peak of activity, again, all detail is squeezed out. In my case, the box is sized to cope in 12 months and the system is new, so activity is scuttling along the bottom of the graph.

However, “poor” though the example is, it told me what was going on across my system at a glance, something about the major tasks we are running, that one problem is currently occurring and that several of the other issues I need to keep an eye out for are not occurring.

That is why I love these screens – I recognise “my” activity patterns from the graph, I now recognise the SQL IDs for my key statements. If I see a pattern in the graph I don’t recognise, I need to check things out immediately. Three or four times over the last 2 weeks I have spotted an issues, started investigating and found out the cause before the Operations desk has even noticed an issue.

Oh, and what is SQL type 189? It is a merge statement. Our implementation of OEM is a little old, it does not correctly interpret that SQL command type. It might be a little old, it is still a lot useful.

Where is Sun? January 3, 2011

Posted by mwidlake in Friday Philosophy, Perceptions.
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2 comments

First of all, may I wish everyone who comes by my blog a heartfelt Happy New Year.
Secondly, I promise I’ll blog more often and more on technical aspects this year than I have for most of 2010.
Thirdly, I’ll admit the title to this blog is nothing to do with the hardware company now owned by Mr Larry Ellison, but is about the huge glowing ball of fire in the sky (which we have not seen a lot of here in England and Wales for the last couple of weeks – not sure about Scotland but I suspect it has been the same). I apologise for the blatantly misleading (and syntactically poor) title.

A quick question for you – It is the depths of winter for most of us, and it has been unusually cold here in the UK and much of Europe. When are we, as a planet, furthest from the Sun during winter? January the 1st? The Shortest day (21st December)? The day the evening start drawing out (December 14th)?
I think many in the Northern Hemisphere will be surprised to learn that we are closest to the sun today (3rd Jan 2011). A mere 147.104 million kilometers from the centre of our solar system. I mentioned this to a few friends and they were all taken aback, thinking we would be furthest from the warmth of the sun at the depths of our winter.

Come the 4th July 2011 it is not only some strange celebration in the US about having made the terrible decision to go it alone in the world {Joke guys!}, but is the day in the year that the Earth is furthest from the sun – 152.097 million kilometers. That is about 3.39% further away and, as the energy we receive from the sun is equal to the square of the distance, does account for a bit of a drop in the energy received. {Surface of a sphere is 4*pi*(R{adius}squared), you can think of the energy from the sun as being spread over the sphere at any given distance}.

Some of you may be wondering why this furthest/closest to the sun does not match the longest/shortest day. As some of you may remember, I explained about the oddities of the shortest day not matching when the nights start drawing out about this time last year. It is because as we spin around our own pole and around the sun, things are complicated by the fact that the earth “leans over” in it’s orbit.

Check out this nice web site where you can state the location and month you want to see sunrise, sunset, day length and (of particular relevance here) the distance from the sun for each day.

I find it interesting that many of the things us most of us see as “common sense” are often not actually right (I always assumed that the shortest day coincided with both the evenings starting to draw out and mornings getting earlier until I stumbled across it when looking at sunset times – I had to go find a nice Astronomer friend to explain it all to me). I also like the fact that a very simple system – a regularly spinning ball circling a large big “fixed point” in a fixed way – throws up some oddities due to little extra considerations that often go overlooked. Isn’t that so like IT?

That lean in the Earth’s angle of spin compared to the plane we revolve around the sun is slowly rotating too, so in a few years (long, long, long after any of us will be around to care) then the furthest point in the orbit will indeed match the northern hemisphere winter. Again like IT, even the oddities keep shifting.

Friday Philosophy – Run Over by a Bus December 3, 2010

Posted by mwidlake in Friday Philosophy, Perceptions.
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7 comments

I chaired a session at the UKOUG this week by Daniel Fink, titled “Stop Chasing your tail: Using a Disciplined Approach to Problem Diagnosis”. It was a very good talk, about having a process, an approach to solving your IT problems and that it should be a process that suits you and your system. All good stuff and I utterly agree with what he said.

But it was a passing comment Daniel made that really set me thinking. It was something like:

You should be considering how people will look after the system after you have gone, the classic ‘what will we do if you are hit by a bus’….. No, I don’t like thinking like that, that phrase… I prefer ‘after you win the lottery and retire to a great life’.

It just struck a chord with me. Mr Fink’s {and I do go all formal when I intend respect} take on this is a far more positive way of looking at the situation of leaving the system in a state that others can look after once you are no longer able to help. The “Bus” phrase is very, very common, at least in the UK and I suspect in the US, and it is a very negative connotation. “Make sure it all works as something nasty is going to happen to you, something sudden, like being smeared across the tarmac by 25 tons of Greyhound doing 50mph, something basically fatal so you can’t prepare and you can’t help any more”. So, not just moved on, but dead.

Daniel made me realise that we should be looking at this from totally the other perspective and that doing so is much, much, much better. “Make it work so that they love you, even when you have gone away to a happier situation – one involving no road-based unpleasantness at all”.

Everyone leaves their job eventually and I like to think it is often for more positive reasons. Like retiring, or a better job {better for you, but a real shame for your old company as they like you so much}, moving to a new area, attempting a dream. Yes, sometimes (depressingly often at present) it is because you get made redundant or things go bad with your managers, or HR take over the organisation. But even so, better to leave knowing you did so with your professional duty intact I think. It’s one way of winning in a losing situation.

If turning the “bus” metaphor into a “lottery” metaphor results in the response in your brain of “well, when I do leave rich and happy, I still want to leave a painful mess behind me” – then it may indicate that you better leave where you are working as soon as possible in any case? As it is not a good situation and you are deeply very unhappy about it.

Up until now I have sometimes used a far more gruesome but less fatal phrase for the concept of making sure things continue after you leave and can no longer help, which is “involved in a freak lawnmower accident”. As in, can’t type but not dead. I’m going to stop using it, I’ve decided that even with my macabre sense of humour, it really is not a good way to think about doing your job properly. Daniel, your attitude is better. Thank you.

Oh, if you went along to the conference you can get the latest version of Daniel’s talk slides from the UKOUG web site (try this link), otherwise, he has a copy here – pick “papers and presentations”. It has lots of notes on it explaining what the slides mean (ie, what he actually says), which I think is a very nice thing for him to have spent the time doing.

Friday Philosophy – The Worst IT Person I Have Met October 15, 2010

Posted by mwidlake in Friday Philosophy.
Tags: , , ,
9 comments

A couple of weeks ago I extolled the virtues of someone I felt was a great person to work with. This week I’m going to do the opposite (and it will be interesting to see which posting gets more hits).

The worst person I have worked with in IT is Mick. I’ve only known a couple of Micks {and if you are one of them, but you don’t know Barry, you are not the Mick}. In an ironic twist of fate I met Mick at the same time I met the best person I have worked with, Barry. We were all in the same team you see, a UNIX sys admin team I got parachuted into. Maybe the vast difference between the two help make them so distinct in my mind.

Mick was very knowledgable and technically very capable. No, that is not fair, he was extremely good. He actually knew all this system admin stuff and several variations of shell programming, perl, C and a few other two-steps-from-assembler type languages. And he was an absolute and utter pain in the behind.

Barry and I did not know much (or in some cases, any) of this sys admin stuff. If we needed to do something and did not know how, Mick was supposed to show us. It worked something like this:

“Mick, I need to copy all the files that were changed last week from this directory on box X to box Y, keeping the directory structure – Can you help?”. Mick would not hear. He suffered from “intermittent deafness” – though he never missed any announcements about free food. You had to go and stand by Mick and wait for him to deem to notice you. If you actually interrupted him he would swear at you and utterly refuse to help, you had to wait quietly. If it was a good day he would deem this acceptable after a minute or two, but he would do his utmost to convey the impression he despised your lack of knowledge and your concerns were beneath his talents… but he would stoop to help.

You would repeat the task you were trying to do and, pausing only briefly to pour scorn on such a trivial thing, he would turn his back and start typing. He’d write a script to do it. “no, no, don’t write it, just tell me the basic commands and I’ll work it out!” No, he insisted on writing the script.

The script would be a thing to behold. Mick would write it in as few lines as possible and the least number of letters. For ages. Oh, he would have a working version in about the time it took Barry or I to explain the task, but he would not give you that version, oh no. He would ignore you until he had made all variables 1 character, took out all whitespace, replaced anything obvious with something obtuse, replaced a small chain of simple commands with one or two arcane commands. Every script was an attempt to win an “obfuscated code” competition. If we waited for the end result, it was impossible for Barry or I to decipher. The only benefit to the process was you would see the commands he was using and you could wander off and start with the unix Manuals yourself and get the job done.

He had other methods with which to demonstrate his greater worth.
Mick would agree to help (under duress of the boss telling him to do so) with an urgent task, but keep asking you to wait all day – then go home without doing his bit.
He seemed to love to intercept anyone coming to you for help, tell them he would sort out the problem for them – only to not. And then tell the user the next day that it was Barry or My problem to sort out. Correct, Mick would not have mentioned this to us.

Mick was fair though, he would treat everyone the same. With scorn. Any expertise in a field he did not know was unimportant and anyone with skills in his field was just competition to be shown who was best. Sadly, he usually was best, if best means biggest smartass.

Over time, as Barry and I learnt stuff (almost never from him), Mick became redundant. Not because we caught him up, not by a long way, but because no one else in the department would ask him anything. They would come to Barry and I. We might be slow and we sometimes screwed it up but we did not sneer and we fixed the problem in a way they could understand.

The reason Mick is the worst person I ever worked with is, unlike people who simply break stuff or lie about their skills or are stupid, he was actually very talented and capable – and yet took a perverse pleasure in not doing so. Mick would put effort into the art of maximizing his unhelpfulness. It was the difference between his potential to help and his drive to not do so that made it so hard for me to deal with him. I’d rather work with a talentless, idiot liar because at least you don’t need or expect much from them.

*sigh*

Friday Philosophy – The Best IT Person I Have Met September 24, 2010

Posted by mwidlake in Friday Philosophy, Perceptions.
Tags: , ,
3 comments

I’ve had the pleasure of working with and meeting a lot of talented and capable people in IT – some of them have even been nice people too :-) {In fact, most people I have met do not match that annoying myth about IT’s reputation for social awkwardness). However, for me one person sticks out in my mind as the best person I have worked with in IT.

It’s Barry. I’m pretty sure none of you have met Barry, and in fact as I knew Barry back in 1996 I’m not so sure I would recognise him (or remember his last name) if I met him now.

Barry and I met when I got press-ganged into a Unix system administration team. I was just getting started at being an Oracle Performance person and knew very little about Unix Sys admin. But, for reasons I won’t go into now, I went home on the Friday as an “Oracle expert” and came in on the Monday to find my desk had been physically lifted and moved into the Unix sys admin corral andI was now a “Sys Admin not-expert”. My protestations were listened to – and then ignored, with the information that if I did “not knuckle down and get on with it”, the money would stop flowing. So, rather dazed and just a tad unhappy with the situation, I sat – and sulked – at my desk. And sat next to me was Barry.

You are probably expecting me to now tell you that Barry knew Unix sys admin inside out and how he took me under his wing and showed me the ropes. Well, he didn’t. I have no idea where they got Barry from, I think he was a pro-C developer, but he had been similarly abused by management and he knew even less about being a sys admin than I did. I at least knew my way around a few monitoring commands like top, w, ps, “glance” etc.

Barry was also not very quick with IT. Don’t get me wrong, he was not stupid, but he was not one of these people who just had an affinity for technology and spent all his spare time building their own media server when CD-ROMS for PCs were still quite new. In fact, he seemed to find the whole of IT to be something of a challenge.

What Barry had though was enthusiasm, commitment and curiosity. Not in an annoying, bouncing all over the place crying “this is great” way, but more a case of “OK, server Falcon has run out of disk space. What can I do about it? How do I find out where the storage has all gone, who is using it and can I get it back off them?”. And he would set to. He’d start with what he knew (which was little more than the “Man” (Online Manual} command in the first week) and work through it. Every few minutes he’d be tapping me on the shoulder and saying things like “Look, you can get information about disk usage here, and map it to the real physical disks by greping for this”.

It was Barry’s attitude that made him stand out, and also his ability to infect you with the same attitude. I started off in that team furious and demoralized, determined to find a new position and resign ASAP. But Barry got over his annoyance and started working. He asked me for advice and discussed the issues over with me, even though I was as clueless as him. When he found something he showed me it. When I found something, he was keen to learn it.

Between us, we got by. We knew very little and it was hard work, but because Barry was not daunted and would keep working on the problem until he had it sorted, he dragged me along with him. I would still be there with him into the evening, sorting something out, when everyone else had gone home. He did not take on every problem people came to us with, he would stick with what he felt was the biggest issue until it was sorted, and he would keep with it, and ask for help, and try what you suggested.

{oddly enough , the worst person I ever worked with was already in this team. Maybe that is why the others left and Barry and I were pulled in!}

It only lasted a few months as we both escaped to jobs more suited to our skills, but I learnt a few things. One was that a crummy job could be made a lot better just by your attitude and another was that some people (Barry, not me) had a real talent for enthusing people and thus getting things done. And also, that you did not have to be highly intelligent or knowledgeable to do a very good job. That’s lucky for me, then :-)

Friday Philosophy – The power of cooperation June 27, 2010

Posted by mwidlake in Friday Philosophy, Perceptions, performance.
Tags: , ,
3 comments

Being the person responsible for the performance of an Oracle-based system can be an oddly lonely working experience. It can also be a very gregarious position as you get to meet a lot of people and discuss lots of different aspects of many systems – all systems seem to have performance issues and so people come along to you, hoping you can identify a “work faster” database setting for them.

But you are often the only person who specialises in Oracle performance. You generally need to be in an organisation that is very large or where performance is key to success for there to be justification for dedicating a person to the topic. To have more than one person dedicated to performance your organisations has to have a very strong focus on getting the best performance out of the Oracle and related systems {or really, really atrocious performance issues :-) }. So usually there is no one else around who is as experienced (or more so) as yourself to discuss such things over with or ask for a second opinion.

Which is why I am very lucky at the moment. I’m working in a team of oracle performance people. There are 2.5 of us (one is a manager with other responsibilities, so he only counts as half). Being able to say “Hey, Dave, What do you think of the wait times on scattered reads?” or “how in heck do I force this nested subquery on a view to use a hash join?” and get some other ideas is very valuable.

What is also interesting is how opinions and preferred techniques on tuning can be different and just as valid. As an example, last week I was working on a poorly performing statement. I was at home and it was the evening, so I was not communicating with the rest of the team. I managed to get the code down from 40 minutes to just under 20 by using a combination of a LEADING and USE_HASH hint. I sent the code back to the user. Only to see that within thirty seconds of each other my colleague Graeme had also sent the user a response, again getting the code down to around 20 minutes. Graeme had pulled a chunk of the code into a subquery factoring “WITH” clause and added cardinality hints. Totally different changes.

So Graeme and I then had a “philosophical” discussion about the different changes {“Mine is best” – “No! Mine is, yours is all bloated and complex”- “Your hint is less future-flexible!!!”}. Only joking, we actually discussed the changes and why we each chose what we did. Graeme commented that is showed that tuning was an art and not a science and I countered that it was a science, as we had both identified where we felt the execution plan could be improved but used different techniques to get there. The thing is, Oracle is so complex and has so many options to influence the optimiser that you have flexibility to chose different tools and techniques.

We had both identified the same main improvement but had each come up with different tweaks for later in the plan.

The end result was that we went with Graeme’s main plan {he is bigger than me} but we pulled in my tweak. That bought the execution time down to around 10 minutes, so about four times faster over all and twice as fast of either of us alone. That is one of the advantages of not working alone.

We also then discussed how we could get this code down to seconds with the use of either Materialized views or changing the process that generated the report to do so incrementally and store the daily results. Until one of us realised we had reached the boundary of compulsive tuning disorder. The report running in 10 minutes was enough improvement to satisfy the business, the report was only going to be run over the next couple of months, so spending a day or two re-working it further was going to be fun – but of no advantage to the business. We told each other to finish for the day. So another advantage of not working alone is that not only do you get more technical input but your help prevent each other losing sight of the overall aim.

It really does help to have two people working on the same area.

{There is a sneaky way of getting beyond being a lone performance specialist. If you are in an organisation long enough you can usually find some other idiot who is silly enough to want to learn more about performance and you can train them up. It does not take long before they know enough to start coming up with things you never thought of. Oracle is, after all, full of many ways to do the same thing and you can’t know it all}.

Friday Philosophy – CABs {an expensive way to get nowhere?} March 11, 2010

Posted by mwidlake in biology, development, Friday Philosophy, Management.
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3 comments

A few years ago, my wife and I went to New York for a holiday. We got a cab from the airport into Manhattan. It was an expensive way to see, at great length, some of the more uninteresting automobile transit routes through New York. We arrived at our hotel a great deal later than we anticipated. And with a lot of our paper dollars no longer in our possession.

I’ve also taken cabs through London, usually at the weekend to get back to Liverpool Street Station. The trip is generally quick, painless and not too expensive, no matter what bit of London is currently being dug up. Those black-cab drivers know their stuff.

Of course, the CABs I refer to in the title of this Friday Philosophy are not private cars for hire. In this context CAB is Change Advisory Board. A term that can make grown developers weep. If you do not know, the Change Advisory Board is a group of people who look at the changes that are planed for a computer system and decide if they are fit for release. My personal experience of them has been similar to my experience of the taxi variety, though sadly more of the New York than London experience.

You might expect me to now sink into a diatribe {ie extended rant} about how I hate CABs. Well, I don’t. CABs can be a part of a valuable and highly worthwhile process control mechanism. Just as proper QA is core to any mature software development process, so CABs are important in getting informed, talented stakeholders to review proposed changes. They check for overall system impact, clashes with other proposed changes that individual development streams may be unaware of, use their own {hopefully deep and wide} experience to consider the changes and to verify Due Diligence has been invoked {that last one is a bit of a minefield and where, I believe, many CABs fail}.

Sadly, though this is often the aim, the end result is too often a bunch of uninformed and technically naive politicos trying to wield power, using the CAB meeting as an extended game of management chess.

I’ve seen CABs trade changes. “I’ll let you have X if I can have Y and Z”. I’ve seen CABs turn down changes because the form had spelling mistakes in it. I’ve seen CABs object to a change that will save the company 5 million pounds a day because it lacked one signature.

That last one just stopped me in my tracks {I’m not exaggerating either, if anything I am underplaying the cost impact of that decision. I saw the figures and I wasted a couple of days of my life checking, 5 million pounds a day was the least I felt I could prove.} We are talking about enough money every day to pay the salary of everyone on the CAB for several years. And they blocked it because the DBA team had not signed off the change. No effort was made to address the lack of the signature in any way, the change was just refused.

The DBA Team had not signed off the change because the one and only DBA Team Leader who was allowed to sign off was on holiday for two weeks. They needed that holiday too, for other but I suspect linked reasons.

Now, I knew the DBA Team Lead and he was a good bloke, he knew his stuff and he was not paid 5 million pounds a day. His deputy was paid even less but was no less talented but she was not allowed to sign off the change as she was not the DBA Team Lead.

That was a CAB gone very wrong. The process of the CAB had been allowed to over-rule good business sense. It was also overruling general and technical sense, but that really is secondary to what keeps the business making a profit.

I’ve seen the opposite of course, technical teams that just apply whatever changes they feel are fit, with no oversight or CAB. To be honest, this less controlled process seem to mess up less often than a poor CAB process as the technicians know they are the ones who will spend the weekend fixing a mess if one occurs. But that mess up will occur eventually, if control is lacking, and the bigger and more complex the IT environment, the greater the chance of the mess up.

So, I feel CABs are good, no make that Great, if you have the right people on them and you have a sensible cascade of authority so one person being away does not block the system. That is quite a bit harder to put in place than a simple “Dave A, John, Andrea, Alex, Raj, Dave P, Mal, Malcolm and Sarah have final signoff” which most CABs effecively become.

But there is one last fault of CABs I want to highlight. They tend to treat all changes in the same way and all changes are not the same. Upgrading the underlying OS is not the same as adding a cardinality hint to one Business Objects report.

If your CAB or change process treat the two above examples the same, then your CAB or change process is broken. Now, in all IT “rules of thumb” there is an exception. In this case, I am truly struggling to think of one. My feeling is that if your change process treats an OS upgrade the same as adding a hint to a report, it is not fit for purpose.

Those are my main issue with CABs. They should be of significant business importance, but nearly always they are implemented with one process to deal with all situations and then get taken over by people with an “Office Politics” agenda as opposed to a “Getting the best job we can reasonably expect done” agenda.

I’m very passionate about this and I have a way I hope can throw this issue into context, an analogy.

Ask yourself this senario.
You go to your doctor with a niggly cough you have had for a week OR you go to your doctor because you almost passed out each day you got out of bed for the last three days.
If your doctor treated you the same for both sets of symptoms, would you be happy with that doctor?

Why are all IT changes handled by most CABs in exactly the same way?

(BTW if you ever almost collapse when you get out of the bed in the morning, do NOT go to work, go instead to your doctor and ask them for a full medical and if he/she does not take blood pressure readings and order a full blood chemisty test, go find a new doctor.)

Command Line or GUI – Which is Best? February 18, 2010

Posted by mwidlake in performance.
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At present I am suffering ever so slightly from “split personality disorder”* in respect of my liking for Command Line and GUI interfaces.

On the one hand, much to my colleagues mild reproach, I use SQL*PLus and not PL/SQL Developer for my day-to-day work. Even worse, I got sick of using notepad to hack around scripts {I am working in a windows client environment and you simply can’t use MS Word with SQL files!} so I have retrograded recently and downloaded a windows-complient ‘vi’ interface and it is soooooo nice to be able to use powerful ‘vi’ commands on my files once more. “:.,$s/^ /,/”. Ahhh, it is so much easier. I can do stuff in 3 seconds in ‘vi’ that would take me 10 minutes in Notepad in a large, complex file. That and, I’m sorry, but notepad seems to be unable to manage a 100MB file, despite me having 2GB of real memory and a decent machine, but ‘vi’ has no problem with it at all.
Even more retrograde, I have direct telnet access to my linux servers and I am getting back to that as it makes me so much more productive. “ls -alrt ^d” for all directories anyone? “df -k .” to see how many data files I can add? Yep, it’s all arcane and means so little to many modern IT “Java/Struts/CDE” people but boy it is direct and fast. I might even dig out that book on SED and AWK.

On the other hand, I have finally (after much very painful discussions back and forth) got agreement that my site probably has access to AWR, ASH and all that good performance repository stuff. So I am hacking around with the OEM screens that focus on performance and snapshots and stuff. Now, I am traditionally not a big fan of GUI DBA tools. Partly it is because I am a bit old and stuck in my ways and partly it is because GUIs are really just “menus of options”. You are limited to what options are available in your DBA GUI tool and you have a harder time learning all the options available or what is really going on “under the covers”.

But with AWR and all those graphs, links and utilities, you can drill down into real problems real time or in the past so effectively that, well, once they start using this tool properly they will not need me at all. It is a fantastic boon to performance management and problem resolution, as well as proactive performance management.

So there you are, I am with Doug Burns on this one, in that I have Learned to Love Pictures. When the Pictures are well thought out and well connected and simple enough to help make sense of a complex system {and Oh Boy Oracle performance has become sooo Complex!!!!}

So right now, I spend half my day in vi/linux/command line world and half of it in pretty picture/GUI world. I think what really makes me happy is to leave behind the half-way-house of text-like Windows World {Windows SQL*Plus, Notepad}.

Just to finish, you can’t mention AWR without someone raising the ugly issue of licence cost and how Evil Oracle Corp were to charge for it. Well, I think it has been established that the guys and gals who developed AWR/ASH did not expect it to become a cost option but it did. And I suspect that what kept it a cost option was the community’s OutRage at it being a cost option. Anything that popular, hey, a commercial company is going to charge for. I still reckon Oracle Corp ballsed up as making it free and helping people use it a bit would have made 90% of customers’ lives easier and would have translated into user happiness and a certain % of sales for training courses to learn more, but heck my day job is to make things work, not maintain sales percentages, so my opinion counts for nowt. *sigh*

(*apologies to real sufferers of Dissociative Identity Disorder, I am using the term in the loose, non-scientific, “common usage” term of “not sure of my opinion” rather than having truly disparate personalities and memories.** And note, I certainly do not mean schizophrenia which, despite the on-going public-opinion misunderstanding, is rarely anything to do with multiple personality disorders or “spit minds” AT ALL, and is more to do with a difficulty in determining between reality and hallucination. ).

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