(Peter Zaitsev) Linux and Unixes have excellent metric of system load called “loadavg”. In fact load average is is 3 numbers which correspond to “load average” calculated for one five and 15 minutes. It is computed as exponential moving average so most recent load have more weight in the value than

(Xaprb) Here’s a way to write join clauses so they are more compact, more readable, and less confusing.

(Giuseppe Maxia) MySQL 5.0 introduces improved SQL modes, which can fine tune the way your server behaves. If you are a long term MySQL user, you may be familiar with the speed for accuracy trade-off. MySQL has a default for each field, and guesses a value when you don’t provide an appropriate one w

(Johan Andersson) In MySQL Cluster a statement like update t1 set counter=counter+1 where pk=1 can be executed in a few different ways with great difference in performance.

(Josh Berkus) Tweakers.net recenty ran an article comparing database performance on Woodcrest and Opteron CPUs. What’s interesting about the article from a PostgreSQL geek perspective is that it validates a lot of PostgreSQL peformance design to date, and a lot of our propaganda about the difference

(Josh Berkus) Tip 4: DELETE is expensive It’s common for application developers to think that a DELETE statement is virtually without cost. You’re just unlinking some nodes, right? Wrong. DBMSes are not filesystems; when you delete a row, indexes need to be updated and free space needs to be clea

(Melonfire) The behind-the-scenes logic of many Web applications often involves repeatedly running the same database query with different arguments, or executing a set of related queries as an all-for-nothing block. To support these requirements, most database systems (including MySQL) support prepa

(Josh Berkus) What follows for the next few posts is a somewhat edited version of a set of advice I am giving to a Sun team on redesigning a C++ application which was built for MySQL, ported to PostgreSQL, and never performance optimized. It occurred to me that this advice would be generally useful

(Leidago) When should you start to worry about MySQL security? When you start to use the MySQL server over an Internet connection. Why? Because that is when your MySQL server is going to be the most vulnerable to all kinds of attacks, such as alterations and denial of service.

(Peter Zaitsev) I already wrote in the blog as well mentioned in presentation there is often a choice you have to make between having prefix index – which can be significantly smaller in size and having index being covering index, which means query can be executed using only data from the index with