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MySQL 5.1 Command line client improvements

 | June 16, 2007 |  Posted In: Insight for Developers

Just found this little handy feature today:

So now if you press CTRL-C MySQL Command Line Client will not exit but will terminate query being executed. This is great as so many queries assumed CTRL-C would also abort running query in previous MySQL versions and I’ve seen many monstrous queries left running without noticing […]

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How simple answer are you looking for ?

 | April 11, 2007 |  Posted In: Insight for Developers

I’ve got an interesting comment the other day saying “I’ve heard Jay Pipes saying indexes with cardinality lower than 30% are worthless, true?” That is interesting question and it has different answers depending on who is asking. A lot of people want to hear simple answers to the questions because they would be overwhelmed by […]

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COUNT(*) vs COUNT(col)

 | April 10, 2007 |  Posted In: Insight for Developers

Looking at how people are using COUNT(*) and COUNT(col) it looks like most of them think they are synonyms and just using what they happen to like, while there is substantial difference in performance and even query result. Lets look at the following series of examples:

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PHP Sessions – Files vs Database Based

 | March 27, 2007 |  Posted In: Insight for Developers

One may think changing PHP session handler from file based to database driven is fully transparent. In many cases it is, sometimes however it may cause some unexpected problems as happened to one of our customers. If you use file based sessions PHP will lock session file for whole script execution duration, which means all […]

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Only Design What You Can Implement

 | March 26, 2007 |  Posted In: Insight for Developers

Working with various projects using MySQL I observe a lot of problems are coming from very simple fact – product is designed containing features which developers do not know how to implement effectively. In many companies you would see “waterfall” like approach for web application development at least on business-development boundary. Business people would dream […]

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To UUID or not to UUID ?

 | March 13, 2007 |  Posted In: Insight for Developers

Brian recently posted an article comparing UUID and auto_increment primary keys, basically advertising to use UUID instead of primary keys. I wanted to clarify this a bit as I’ve seen it being problems in so many cases. First lets look at the benchmark – we do not have full schema specified in the article itself […]

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