Upgrade Problems

Adventures in Vistasitting

After Christmas last December, I took some of my hard-earned gift cards and cash and bought an eMachines T3516A desktop computer for the family’s general use. It was a pretty good deal. It was more computer that we’d need for daily computing and they actually took $50.00 off of the price of the computer if I’d take home a monitor and printer. Another bonus for me was that I’d get a free upgrade to Windows Vista when it was released a month later.

I submitted my forms and got my disk. I was hesitant to leave XP, since it had done me no harm, but I do love the latest and greatest. I ran the upgrade and after the first reboot, I got a STOP: 0x0000005C blue screen error. Very nice. At the time, there was no help to be easily found on the internet, so I had to reverse the upgrade and learn the intricacies of bcdedit to get things back to normal.

A few months later, I decided to give it a go again. Same STOP: 0x0000005C blue screen error. Google revealed that this was probably a BIOS issue. Nervous about flashing the BIOS, I reversed the process and waited again.

This past weekend, I gave it one more shot. Same error. However, this time I found a great site called The Unofficial eMachines Tech Info Site that had the download and offered some reassurance that this process would probably go well.

I gave it one last shot and actually got past the first reboot. Vista got completely installed. However, on boot (normal or safemode), it would hang on loading crcdisk.dll. None of the solutions I found had anything to do with me, so I had a much more painful rollback and am now back to faithful XP.

I think I’ve sworn off upgrading this eMachine to Vista for good.

Code Optimization

What Cost, Functions?

This post is about Sql, specifically in the Sql Server RDBMS, but I believe that the principles will hold up across platforms.

If you are using a function in a WHERE clause in your SQL, like the following:

SELECT a.id, a.name
FROM some_table a
WHERE a.hash_value = fn_hash_function('value')

The function will be evaluated for every row in your table. This will result in performance decreasing exponentially as your table grows.

A better way to accomplish this query is to do the following:

DECLARE @input_hash varchar(1000)
SET @input_hash = fn_hash_function('value')

SELECT a.id, a.name
FROM some_table a
WHERE a.hash_value = @input_hash

This code will only evaluate the function one time and as long as you have the comparison column indexed properly, you will see very impressive results. On one query on my local machine, Sql Profiler showed that query that was taking over 7000ms begin to return in about 70ms.

The performance gains in that exact instance were less drastic on a Sql Server running on an actual server (it had just been powering its way through), but in time it would have gotten unbearably slow, as well.

Hope that helps someone.

Uncategorized

Greetings

Well, I’ve struck out on my own. After having a private blog over on Blogger and posting innumerable quizzes, movie reviews, and jokes, I started to get quite bored. I had the idea to start this blog (and even had the name picked out), but just didn’t really have the motivation to get everything set up.

I’ve finally gotten that motivation and now I’ve struck out on my own with my own installation of WordPress. I plan to blog mostly about everything technology-related in my life (though mostly about software).

It may not be ground-breaking, but hopefully it will be interesting!