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Comment by jcampbell1 | Hacker News Reader

I reach the opposite conclusion. These are premature optimization tweaks which means tons of people are using SQL successfully without knowing them.

You could argue CSS is a failure, because designers don't know that

    #sidebar .widget

is slower than

    .widget

I'd argue that it is evidence CSS is a success because it makes no real difference, and people opt for the more readable solution.

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I tried to think of an analogy of someone dragging CSS into this conversation, but I couldn't. Maybe like throwing a dead cat into a room full of aristocrats?

You said cats and aristocrats and all I could think of was the movie The Aristocats.. so to me they seemed related :x

Do you have a good link for numbers on this css point? I would expect speed differences, but my naive view would be that they wouldn't be much.

The difference is not worth talking about at all.

The difference is probably .1us. You may find it interesting why browsers match CSS selectors from right to left (though this is a useless bit of trivia). see:

http://stackoverflow.com/questions/5797014/why-do-browsers-m...

>These are premature optimization tweaks

How can you apply a blanket "premature" to this? The questions are simply "can this be improved?". There's nothing premature about it, it is a quiz.

It is a reference to this well known quote:

"Programmers waste enormous amounts of time thinking about, or worrying about, the speed of noncritical parts of their programs, and these attempts at efficiency actually have a strong negative impact when debugging and maintenance are considered. We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%." --Donald Knuth

I am aware of that quote. And that is precisely my point, he is talking about premature optimization, not optimization. What could possibly make you think that the questions in this quiz are examples of premature optimization?

Except using indexes is a major part of developing for a database. In many simple schemas, performance will completely break down without proper indexing. That's a bit different than spending time investigating if for-each is faster than a traditional loop.

> Except

I am not sure what the exception is about. I agree 100% with the rest of your comment.

My exception was to the idea of this being a premature optimization (sorry, I probably should've replied directly to your comment with the CSS example)

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