Friday Philosophy – Solving Simple Problems By Asking The One Key Question.

For many of us solving problems is a large part of our working life in IT. This is especially true when it comes to getting features of a product to do what it is supposed to do or even making a bit of hardware work the way it should. And, if it is a printer, work in any way at all! Often the solution is simple but we ask ourselves the wrong question. I’m going to use this pair of garden secateurs as an example of this. Trust me, go with me on this.

My trusty secateurs as a metaphor for almost all IT problems

I’ve had these secateurs for many years. For the first few years these secateurs worked wonderfully, but in the last 2 years they have not been working so well. They just don’t cut all the way through stems & small branches, you have to almost pull the piece off that you want to smoothly cut away. I was having to squeeze the handles harder and harder to complete the cut. And now it seemed to make no difference how hard I squeezed, they would not cut cleanly. This is like steadily increasing the size of the SGA to improve query performance, getting some initial gains and then nothing more.

The trick with any such cutting device is to keep the blade sharp, and I do. A few strokes with a needle file every few months keeps the blade sharp. The other issue with an anvil-type pair of secateurs like this is to keep the anvil, the flat area the blade comes down onto, clean and the little central gap clear. The blade closes down on the anvil and the thin gap allows the blade to *just* drop below the main face of the anvil and cleanly cut the stem. This is like the regular maintenance you do on a computer system, like cycling out redundant data or ensuring there are no accounts for staff who have left or rebuilding all your indexes ( 😀 ).

Only, no matter how much I sharpened the blade or cleaned out the anvil the secateurs would not make a clean cut. Ahh, I know. If you look at the above pictures you will see on the blade that the area closest in to the pivot is silver, it is where most of the wear is. Had the blade worn back into a curve so that the key part of the blade was not cutting all the way through? I used a flat piece of metal and checked the blade. Well, the far end was a little proud so I worked on it with the file and got the whole blade totally flat and sharp along the whole length. It was sharp enough so that when I pulled garden twine over the blade it cut straight through with ease.

But they still would not cleanly cut through a stem. I oiled the pivot, for no reason other than blind hope (just like changing configuration parameters for something when you really know those parameters have nothing to do with the problem). I sharpened the blade again (I rebuilt my indexes again). The blade was wickedly sharp, it was flat, the anvil was clean, these secateurs had always worked so well. So I asked the question. Or, more accurately, shouted it at the offending thing:

Why wasn’t *IT* working?!?!!

And that is the wrong question. But it’s usually our attitude to any piece of software or hardware that is not doing what it should. We beat the desk and swear and shout “why won’t you work you piece of crap!!!”

At this point you need to stop and ask a subtly different question:

What is it I don’t understand?!???

The two questions are similar but the key thing is they come from different directions. When you are screaming at the unresponsive printer or swearing about the SQL hint having no effect, your mind-set is that the thing is broken or has a bug or is in some other way not doing what it should. It’s the printer’s fault. The manual is wrong on setting up the feature. This thing is not doing what it should.

Well, yes it is not doing the required thing – but given other people can get the feature to work or the printer was working last week, the problem is unlikely to be there. The problem is actually that I am not understanding something. And it could be very fundamental, so ask the most basic things first. For the printer to print something it needs to be on and I need to send the file to it. Is it on! OK, maybe not that basic, but are you sending the file to the right printer?

Getting back to my example hardware, the blade is sharp enough to cut, the face it is cutting onto is clean, there is no issue with the pivot. What does it need to *do* to cut? The blade needs to come down on the anvil. I closed the secateurs and held them up to the light.

Note, I slightly emphasised the gap for the sake of the photograph

Ahhh, there is a gap! If I squeezed really hard the gap would shrink, but not completely close. The problem is not the blade, it is not the anvil, it is something else that is stopping the two coming together. The problem is elsewhere. And it is simple. And this is often how it is with software & computers. Yes, sometime the problems are very complex or have several confounding factors, but when you are trying to get something to just work, the problem is usually one of missing something obvious, which is usually being impacted by a component you are not currently swearing at.

This is just like last time my printer would not respond to requests to print from my laptop. I’d checked “everything”, swore at the printer, turned it off and on a few times, kicked the cat, sacrificed a small child to the printer Gods. I stopped and I did the “what do I not understand” thing. It turned out that due to a brief power outage a few days earlier my laptop was connecting to the internet via my neighbour’s router not mine (we have a mutual agreement to share due to the connection issues of living in a field and that we use different service providers). The printer and the laptop were not on the same network.

If you look at the secateurs in full you will notice that between the handles there are two plastic lugs that come together. I’m guessing they stop you squeezing the blade deep into the anvil, potentially damaging both blade and anvil. Over the years of sharpening I had worn away the blade enough that these plastic lugs were now preventing the blade and anvil coming together. Especially as, due to my frustration, I had given the blade a really thorough sharpening. That’s why I had been having to squeeze the handles harder & harder until eventually no effort would get a clean cut. I got that needle file out and reduced those lugs by a millimetre or so. The blade now closes on the anvil and, being about as sharp as it has ever been, they cut wonderfully. The solution was wonderfully simple and it took me all of 2 minutes to implement once I had worked it out.

With my first “increasing SGA” example, I was squeezing hard/giving the database a larger buffer cache, and that helped, but the real issue was the sorts were spilling to disc. I needed to increase the PGA (or process less data).

beautifully closed secateurs

You see, it was not that the secateurs were maliciously working against me or that the components that usually needs some maintenance needed it. It was that I was not understanding something – something very simple & fundamental it turns out. Rather than repeatedly doing the maintenance steps that had worked before but now were not, I needed to stop doing what was no longer working and ask what had changed.

When you are solving problems and it’s got to the swearing stage, it’s time to walk away for 5 minutes, have a cup of tea, and then come back and ask yourself “what do I not understand?”. Best still, do this right at the start. Though to be fair I’m not very good at that, I always get to the swearing stage before I decided to question my understanding.

Especially with printers. I bloody hate printers. Printers are sentient and out to get you.

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