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Just a pointer to an update January 27, 2010

Posted by mwidlake in Testing.
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2 comments

This post is really just to highlight that I finished salvaging Yesterdays Post. If you found it of any interest before, go have a look at the end. If not, heck go look at dilbert. As funny as ever but BOY is that web site suffering from advertising hell and slow performance…

Update – I removed the link to the dilbert site because I went over to the site the other day and got one of those “Your PC is INFECTED” cons popping up in my browser. You know, the ones that tell you you cannotget rid of the infection without their software, but the only infection is their software. I could not get rid of it without shutting down my browser session (and yes, I have PC security software that is updated every day).

What were you doing 10 years ago? December 24, 2009

Posted by mwidlake in Perceptions.
Tags: , ,
4 comments

It is coming towards the end of December 2009. What were you doing 10 years ago today? If you were at school or college I don’t want to know, it just depresses me. You might have been doing last-minute Christmas things, you could have been traveling to see friends , loved ones or maybe {and often less pleasurably} relatives. If, however, you were working in IT I probably know what you were doing:

You were somehow involved in preparing for “The Y2K bug!!!” (Cue dramatic drum roll, ominous music, thunder-and-lightening video and the quiet shrill laughter of consultancy firms running all the way to the bank).

Remember that? I’m a little surprised not to have seen anything much in the media yet celebrating it, {I’ve not seen it in the UK anyway}, which is odd as it was such a very big deal back then. You remember? All the nuclear power plants were going to blow up, air control systems go haywire, bank systems crash and generally the whole of modern civilisation was going to crumble.

It did not of course. It’s biggest impacts seemed to be firstly to give old Cobol and Fortran programmers a bit of a financial boost to help them bolster the pension fund and secondly so much time, effort and planning was spent on Y2K preparation that 75% of other IT programs were shut down to cope. There certainly seemed a little less work to be had in the immediate aftermath.

I never decided who was more to blame for the hype and the fear. The Media, who can never pass a chance to boost revenue by outrageous scare tactics, or business/it consultancies who can never pass a chance to boost revenue by… I better stop there, in case I ever decide to go back to working for a consultancy.

I personally learnt a couple of things.

One was to prepare. In my particular case, I had planned a big Y2K party with a bunch of friends, hired a big house to hold a dozen of us plus kids and found somewhere to buy big fireworks from. All in 1998. And for 18 months before the event told anyone I went to work for that I would not be available for that particular week. I put it into my contract. Of the two or three companies I picked up contracts with during that period, none of them batted an eyelid when I mentioned this. Of course, this meant nothing. With 3 months to go before Y2K, the missive came rolling out from top management that no one, absolutely no one in IT was being allowed to take New years eve off.
I said to my boss “except me”. No, no exceptions. “It’s in my contract, I stated when I joined I was not available that week”. No exceptions. “Bye then”. Huh? “Well, I said at the time and I am sorry to upset you, but you see, this is a job, we had an agreement and what I have organised is my life and well, you lose”. I was a little more diplomatic about it, but I insisted. After all, we had fully Y2K tested the app I was responsible for and I had an agreement.
I had the week off (with a mobile phone by my side, admittedly, but I was not in a fit state to do much by the time midnight came around). I learnt that if you have an agreement and you calmly refuse to capitulate, and you negotiate a little, you can avoid “no exceptions”. {My friend Nasty Mike took the more direct approach of swearing loud defiance. He won also, but maybe with more bad feeling…}

The other thing I learnt was that companies will not pay less than they expect for a job. The five of us had written this app and it used four digit year dates all the way through the system. It was on Oracle 8. It worked. But no, Top Management wanted the system Y2K proving. So they asked a company to test it. This company wanted something like £50,000 to test it and it was to come out of our development budget. Ouch. That was pretty much half the budget.
So one of the team put forward a proposal to Y2K test the system via their company, for about £5,000.This was refused; it was too cheap to be believed.
So we put exactly the same proposal forward through another of our companies for £15,000 plus expenses and an exorbitantly hourly rate if extra work was needed.
This proposal was accepted.
So we did the work, we ran all the tests we specified, rolled the system past Y2K, repeated the tests, then…did a full refresh of the O/S, oracle and the app and recovered a full backup from before the initial tests. We were delayed by 24 hours as central IT screwed up the full oracle restore, so we got to charge the exorbitant hourly rate.
We handed the test results pack to the central IT team and their one question was “Why had we refreshed the O/S and re-installed Oracle? Well, we said, how do you know that going past Y2K had not set some internal variables within the O/S or the database that just setting back the system clock would not fix? The O/S is a complex thing.
The head of central IT looked ever so worried. No one had mentioned that before. And they had spent a lot on external Y2K testing consultancy…

Isn’t business odd at times?

Friday Philosophy – Statistically Significant November 27, 2009

Posted by mwidlake in performance, VLDB.
Tags: ,
3 comments

There are very few generalist Oracle DBAs around, and very very very few expert generalist Oracle DBAs. Tom Kyte might count, but I’m sure if you pressed him he would admit to knowing nothing about {some key aspect of being a general DBA}. That is because to be an expert on something you have to spend a lot of time on it. Oh, and learn. {I’ve spent a lot of time around my wife but she still confuses me, I just don’t seem to be able to learn}. Oracle is simply too wide a topic to be able to spend a lot of time on all of it, even if by “Oracle” you mean just the core RDBMS technology, which I do. You have to pick an area.

Pete Finnigan specialises in security, Julian Dyke on RAC and Internals, Doug Burns on the relationship between the database and cuddly toys. Oh and ASH/AWR.

So I ask myself, what is my specialty?

Well, if I go on the last 5 working years of my life, it would probably be Oracle Database Statistics. Which is quite ironic given my woeful attempts with Statistics when I tried that maths ‘A’ level all those years back {for non-UK people, an ‘A’ level is what you do at age 17- 18. It’s that point in maths when most of us are convinced logic is replaced by magic}. I’ll go further and say I specialise in Oracle Database Statistics on VLDBS. Maybe even more specific, Gathering and Maintaining Oracle Database Statistics on VLDBs.

Not a very sexy-sounding specialty is it, even in the context of IT technical specialties. I am sure that if I was to tell a lady I wish to impress that I was “a specialist in gathering and maintaining Oracle database statistics on VLDBs” then I would soon be standing alone as she looked for an accountant to talk to {I refer back to my comment on my wife, I repeatedly try to impress her with this line and she never fails to walk away}. Heck, I could spend all my time at the UKOUG Conference next week and struggle to find someone who would respond positively to such a claim to greatness.

But the situation is that I have had to deal with the failures and idiosyncrasies of this area of Oracle for 4 major clients on a dozen or so systems and have discussed it with half a dozen other people who have had challenging times with it. And even now it trips me up all the time. Because, frankly, some if it is not very well implemented (choking automated stats gathering job anyone?), different parts work in different ways (if you state a statid, statown and stattab when you SET_TABLE_STATS the values go into the stats table, if you state them for GATHER_TABLE_STATS, the gathered values go into the data dictionary and the OLD ones go into the stats table – yeah, I know, if you did not know that you are now going ?huh?), some of it is wrapped up in a blanket of confusion and secrecy (what exactly DOES the automated stats job do and when you say “GATHER AUTO” what exactly will Oracle do automatically?).

Thankfully the secrecy side is reducing as Oracle (and others) say more about how some of these things are controlled or decided “automatically” , but then the world shifts under your feet with new versions of Oracle. Stats gathering under 11g is far more open to control than 10, but as my current client is not on 11g then I can’t spend too long looking at that.

So currently I am a expert in 10g Gathering and Maintaining Oracle Statistics on VLDBs. Now if that is not pretty damned specialist then I don’t know what is.

I should blog technical details on all of this {sadly I know the answers to the things I mention above}, but I suspect people would go “Hmmm, interesting…..” in that kind of “who in heck needs to know that! I’m off to do block dumps of temporary segments” way. But if you think otherwise, let me know.

Besides, I am being very, very poor at getting on with the Partition stuff I want to do, even though I have half-written about 4 more posts on it. I need to stick to that for my technical blogs for now.

That and I kind of shy away from being an expert in such an unexciting area, I might get offered {oh dear lord not more} work in it.

Thankfully I also specialise in beta testing new features of Oracle for clients in the travel and media industries, where on-site work in exotic locations is, at times, required… If anyone has any opening in that field, drop me a line :-)

Keeping the server and storage utilisation high October 9, 2009

Posted by mwidlake in performance.
Tags: ,
6 comments

A friend of mine sent me this today, from an old site of mine:

******************************************
From: John Smith
Sent: 07 October 2009 10:08
To: Sarah Sims
Cc: DBA team
Subject: RE: Performance issues on your Test servers
 

Hi Sarah,

Please could somebody tell us why this query is running repeatedly on your database:

SELECT composite_key , exact_time , object_type , table_name , user_id , xml_data FROM usr1234.acramendlogshd ORDER BY 2;

It’s very prominent in both of the 1-hour time slices I’ve analyzed so far, and is fetching the entire 12GB 20M-row table.  This is so absurd that it looks almost like a programming error!

The same table in the production environment is almost the same size, 18M-rows.
 
Regards,

John
******************************************

******************************************
From: Sarah Sims
Sent: 07 October 2009 11:18
To: John Smith
Cc: DBA team
Subject: RE: Performance issues on your Test servers

John,

This would be the ACRALS service which has a bug in it currently which means that it runs continuously but never achieves anything.

Sarah
******************************************

So, not only inefficient and pointless but known to be inefficient and pointless. And still on.

And as some of you may suspect, yep this is a third party application where changing the code is forbidden. Seems like testing before release might also be forbidden….

Hey, it’s not my fault I can’t spell. June 10, 2009

Posted by mwidlake in humour, Perceptions, Private Life.
Tags: , ,
1 comment so far

*Sigh*
I just got pinged by someone to let me know of some spelling mistakes in my blog. I know, I know, just leave me alone OK?!

Do you remember doing the “colour blind” test at school? {And, for our American cousins, “color blind”}. You know, you are shown a few images made up of dots, with numbers in them.

Most of the colour blindness images are far less obvious than this

Well, most people are shown 5 or 6 images and shout out “8”, “16” etc promptly five times and are then shown out – nothing more is said. Some people cry “7”, “34”, “dunno, give me a clue” and after 10 or 12 images get told they can’t distinguish blue & green or red & brown or something and so can’t drive trains or fly fighter planes… Me? I was in there for 5 minutes, coming up with what must have been very confusing answers. They even started showing me the same images again and I remember occasionally going something like “it’s 16 not 6, isn’t it”. Eventually they told me my colour vision was fine and threw me out as a time-waster. I wonder if I can fly fighter planes?

What they should probably have spotted (and a school teacher friend of mine got quite angry about this when I told her this story, as she thought they should have spotted this even back in the late 70’s) was that I could not read for toffee – as I have mild dyslexia. She had been taught how to identify dyslexia in children and one of the easiest ways was, she said, issues with the colour blindness test but without being colour blind.

When I read things I don’t do what a lot of people do, which is kind of pick up the start and end of long words and “see” it. I do it in little spirals. I do not know that I can explain better than that, but if I hit a long word (more than six letters) I start at the begining, flick to the back of the word and work back and if the two don’t meet I spiral in. I wonder if there is a cunning lexical trick I can sell to Oracle Text on that one?

It’s no where near as bad as many, heck I’ve managed to get by OK with it, but spell checkers have been a boon to me. The problem is, I don’t always remember to use them and, even if I do, a word spelt wrongly but is itself a correct word will not be picked up. I know, many packages now also have Grammer Checkers that could pick some of it up, but I find Grammer Checkers so infuriatingly useless, I turn them off.

So, sometimes my spelling is terrible. It’s because I have an IQ of 73, OK? The thing is, I probably got pinged in every exam I took because of it {except Maths, where in all honesty I got past the exams at age 16 and then it all stopped being logical. Sorry Mr Winters, I did my best as you know, but my brain could not do all that more advanced stuff}. I even got bollocked told off during my degree for carpals and carpels but heck, to me both read crapals.

I had particular fun a few years back when I introduced Oracle Partitioning to British Gas. No one had used it before but I had a quiet little application that I was passing over to the production DBAs to look after that did. So, I went over to Hinckley (oooh, thats a doozer to spell) where all the proddy DBAs lived and gave a presentation on Partitioning. Except I was doing it with white boards and OHP and every time I spelt Partitioning I wrote “rtit”, then went back and put in the “Pa” at the start and then tried to finish it off. Usually I managed. That was what prompted the chat with the teacher, I was telling her how that sort of thing happens to me and it’s annoying and she asked about if I had ever been tested for colour blindness.

So, there you go. It’s my excuse. Now you know that either I am right, or I have munchausens syndrome {just look it up, OK? Try this here}.

The odd thing? I can’t always spell “who” but I never get “Dyslexia” wrong.

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