(Peter Zaitsev) Working on performance optimization project (not directly MySQL related) we did a test – creating 100 files writing 4K in the random file for some time and when checking the read speed on the files we end up with, compared to just writing the file sequentially and reading it back.

(Roland Bouman) The MySQL User’s conference will be held in less than a month from now!!!

(Peter Zaitsev) I posted a simple INFORMATION_SCHEMA query to find largest tables last month and it got a good response. Today I needed little modifications to that query to look into few more aspects of data sizes so here it goes:

(Justin Swanhart) Typically, when choosing a composite index structure, your favorite DBA will tell you to put the most selective columns first. Now, when I tell people that I tend to get a few blank stares, so first, what does selective really mean?

(Giuseppe Maxia) One of the major additions to MySQL 5.1 is the the event scheduler. It is an internal scheduler, which does not need any help from the operating system. As such, it works independently in every platform.

(Arjen Lentz) I frequently see a question fly past on why an expression like WHERE col = NULL does not come up with the desired result, even though it superficially looks perfectly sane. To address this, we can recap some high school maths, and at the same time finally find out that some things lear

(Peter Zaitsev) What MySQL honestly was never good at is giving good helpful error messages. Start with basics for example – The error message in case of syntax error gives you information about tokens near by but little details:

(Giuseppe Maxia) MySQL 5.1 introduces the plugin interface, a series of API that allow the load and unload of server components at runtime. The idea behind this architecture is to make MySQL server really expandable.

(Peter Zaitsev) For large number of online applications once you implemented proper sharding you can consider your scaling problems solved – by getting more and more hardware you can grow. As I recently wrote it however does not mean it is the most optimal way by itself to do things.

When working with databases that allow for transactions you will often see the term ACID compliant.