Oracle Scratchpad

November 12, 2010

Autumn

Filed under: Non-technical — Jonathan Lewis @ 6:58 pm GMT Nov 12,2010

… (or “Fall” for speakers of American) has arrived in the UK – and once again I am reminded how gardening and trouble-shooting are just two aspects of the same problem.

I have several trees in and around my garden, including two rather large Oak trees, and at this time of year it takes a couple of hours at the weekend to rake up the fallen leaves. The comparison with solving performance problems is obvious:

Every Saturday, I look at the leaves on the ground and the leaves still on the trees and quite often manage to persuade myself that there’s no point in doing anything just yet.

On the Saturdays when I decide that I really do have to rake up the leaves I aim to clear about 99% of the problem – there’s no point in clearing to 100% because if I go for perfection it’s only going to last a couple of minutes before more leaves start coming down or blowing in. Of course, after I’ve spent ages clearing 99% of the mess, my wife (the end user) is quite likely to say: “you haven’t finished yet”

After I’ve done a really good job raking up enough leaves I look up at the trees and know that all those leaves are going to be heading my way and I’m probably going to have to do it all over again next week, and there’s nothing appropriate that I can do to stop it happening.

 

August 26, 2010

DMCA

Filed under: Non-technical — Jonathan Lewis @ 9:41 pm GMT Aug 26,2010

Some readers have noticed that a few links to my blog seem to be broken. Don’t panic, it’s not permanent it’s just the result of Don Burleson losing his temper.

Let me start by telling you about DMCA, the “Digital Millenium Copyright Act”. DMCA is a mechanism designed to protect Internet service providers (ISPs) from being sued over content published by their customers by allowing them to act as a communication channel and staying out of the line of fire.
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July 24, 2010

Recovery

Filed under: Non-technical — Jonathan Lewis @ 7:11 pm GMT Jul 24,2010

I’ve been on holiday for the last few days – the last few posts were dated to publish themselves in my absence – and got home last night. First thing I did, of course, was to download my email … second thing the machine did was to declare an automatic software update and destroy the hard-disk on reboot. So I’ve downloaded but not read all the mail that was sent to me after 8:05 a.m. (BST) on Friday 16th July.

Luckily 8:05 am was when I took a backup of the system – as you do when you’re about to to on holiday – so I haven’t lost any data, except for those emails. So if you sent me anything important over the last week, please send it again.

Footnote: while I had a backup of all my data, I discovered (as one does until you practice recovery very regularly) that there were bits of information I hadn’t catered for: my address book and my mail rules, neither of which I had been exporting regularly, both of which are quite useful.

July 11, 2010

Don’t Knows

Filed under: Non-technical — Jonathan Lewis @ 6:29 pm GMT Jul 11,2010

One of the biggest problems in learning is that you don’t know how much you don’t know, and this raises two questions:

  • how do you find out that there are huge gaps in your knowledge that need to be filled ?
  • how do you know whether or not the material you’re learning from is any good ? (There’s a LOT of garbage on the internet.)

I can across an interesting little post from John Scott (of ApEx fame) a little while ago that shows the effect of the first question very clearly.

May 15, 2010

Fame

Filed under: Non-technical — Jonathan Lewis @ 10:24 am GMT May 15,2010

I’ve just received an email telling me that I’m a linchpin – according to this picture on Seth Godin’s website.

August 6, 2009

Travelogue 2

Filed under: Non-technical — Jonathan Lewis @ 2:37 pm GMT Aug 6,2009

I rarely make a fuss about the places I go and the things I do, but I had another one of those moments last week when I felt the weight of history.

I was in Capetown, South Africa, on a glorious winter week-end, and I had strolled out to the Waterfront. Walking back to the city at sunset, I was suddenly hit by a feeling of the immense age of the mountains compared to the (relatively) new city nestling in the hollow at their base.

Naturally I’d forgotten to take my camera with me on my walk, and my mobile phone couldn’t cope with the low light – but here’s a picture I’d taken (on my phone) on the way out to the Waterfront a couple of hours earlier. If you imagine the perspective from a mile further away, with the city looking about one third of the size and the mountains unchanged, you may get an idea of the image that made me stand and stare.

capetown_02a

Now that I’m back home I’ve got a load of comments that need answers – so you can expect to see my name as the author on just about every comment on the comment list for the next two days.

June 8, 2009

Book content

Filed under: Non-technical — Jonathan Lewis @ 7:12 pm GMT Jun 8,2009

Rob Freeman raised an interesting topic on Oracle-L a couple of weeks ago with the following:

My question is, what constitutes Oracle Book Writing mal-practice (and I pray I’ve never committed it).  Certainly mistakes crop up in books all the time, I’m as guilty as any writer of this. This chapter I’m reading though, in an effort to get the reader to doing something quickly, does not lay any foundation, skips critical steps and actually prompts them to do what I consider some very dangerous things.

The posting didn’t really generate a lot of discussion – which is a shame – and my privileges to write to Oracle-L lapsed some time ago, so I’m writing my response to Rob’s observations here.

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January 14, 2009

Books

Filed under: Non-technical — Jonathan Lewis @ 8:38 pm GMT Jan 14,2009

When I was in Salt Lake City a few months ago, Barbara Matthews (one of the organisers of the SLC Oracle User Group) asked me for my “Top 10” books about Oracle.

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October 9, 2008

Travelogue

Filed under: Non-technical — Jonathan Lewis @ 5:20 pm GMT Oct 9,2008

In the last five years I’ve visited more than thirty different countries and seen a lot of wonderful sights – some natural,some man-made. But Sunday was the first time I’ve walked into a hotel room and been overwhelmed by the view.

I was in Athens, staying at the Hilton, in a room facing the Acropolis – and most of the wall was glass, so the impact of the view as I walked into the room was staggering.

The picture, inevitably, doesn’t do justice to the scene. When I tried to include the sweep of modern Athens the Acropolis got lost in the picture; when I tried to capture the Acropolis I lost the sense of how it grew out of the surrounding cityscape – this is the best I could do.

When you’re there, the feeling is of an immense sea of modern buildings, with the Acropolis as a giant focal point that spreads a layer of solidity and calm over everything about it. It is an extraordinary contrast.

June 10, 2008

Firefox

Filed under: Non-technical — Jonathan Lewis @ 2:53 pm GMT Jun 10,2008

Here’s an interesting URL that I found by following an incoming link a little while ago.

If you run Firefox as your web browser, this “Customizegoogle” add-in allows you to “filter spammy websites from search results”. (It’s got a lot of other features, but this one seems likely to be the most useful to Oracle users).

I’ve got Firefox on my Linux RAC stack – but I may have to download it for my Windows boxes too, especially the laptop which is the machine I use for most of my writing.

Update: And here’s a URL that should let you do the same thing with Internet Explorer, too.

Update 2: A link to the “Oak Table Safe Search” that limits Google to a few sites that tend to give good information. It will miss some good sites and will occasionally provide an indirect link to some less desirable pages – but generally it’s a good starting point.

Update 3: A couple of interesting developments relating to Google Chromeand “Content farms polute search engine results”.

January 2, 2007

Humour (possibly)

Filed under: humour,Non-technical — Jonathan Lewis @ 9:22 pm GMT Jan 2,2007

This may not translate well because of the colloquialisms, but it seems appropriate for the current time of year (early January) in the UK.

You may have noticed that I spend quite a lot of my time explaining why something is a bad idea and should be treated with caution. Occasionally this has resulted in complaints that I keep pouring cold water on everything. The best response to this comment is one I first heard many years ago:

“Cold water is the natural result of hot air meeting thin ice”.

November 13, 2006

Trust

Filed under: Non-technical — Jonathan Lewis @ 10:23 am GMT Nov 13,2006

Here’s a guideline on how much trust to place in advice you get from articles about Oracle published on the Internet (even the ones published by Oracle Corp.):

  • If it’s not dated – don’t assume it’s true
  • If its date is more than about 18 months old – don’t assume it’s (still) true
  • If there’s no version number – don’t assume it’s true
  • If it’s not your exact version number – don’t assume it’s (still) true
  • For ‘technical implementation’ details, if there’s no platform mentioned – don’t assume it’s true
  • For ‘technical implementation’ details, if the platform’s not the same as yours – don’t assume it’s true
  • For ‘technical implementation’ details, if the feature set described does not match yours – don’t assume it’s true
  • If there’s no rational justification supplied,  and no repeatable test case – don’t assume it’s true

And even when all the details are perfect and there is a repeatable test case – and even after the repeatable test case produces the same results – ask yourself this question:

“Could there be a different explanation for the same set of results and, if so, how badly could this advice damage my system and how hard would it be to test my alternative hypothesis ?”

Once you’ve got through that lot – then you might be safe trying the advice on a development system.

Update 19th Aug 2010

Since this note was more than 18 months old it needed to be validated (according to its own standards) – and there were  a couple  more thoughts that crossed my mind:

  • If the only justification for a claim is an extract from the Oracle documentation then check that the quoted article (still) exists – and if it doesn’t exist or the quotation isn’t accurate don’t trust the claim.
  • If the only justification supplied in an article is an extract from the Oracle documentation don’t quote the article to someone else, supply the link (or reference) to the original documentation – it’s more likely to be in context, and it’s more likely to be corrected and brought up to date (eventually) if it’s wrong.

Update (20th Jan 2013)

Time passes so quickly – I should have reviewed and re-affirmed this item months ago. On the other hand, I’ve just decided it’s not really about Oracle (exclusively) and it’s definitely not a detail of technical implementatin, so it doesn’t really apply to itself. It’s going be valid for years.

Update (19th August 2015)

I just failed to follow my own guidelines – see posting referenced by the last pingback below – so I decided to remind myself of the comments I made all those years ago. And then had to insert one more caveat to the list.

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