MySQL keeps many different files, some contain real data, some contain meta data. Witch ones are important? Witch can your throw away? This is my attempt to create a quick reference of all the files used by MySQL, whats in them, what can you do if they are missing, what can you do with them. [...]
WHAT TIME IS IT? This post started with a simple question: “Does the function NOW() get executed every time a row is examined?” According to the manual, “Functions that return the current date or time each are evaluated only once per query …. multiple references to a function such as NOW() … produce the same [...]
In my business (weather) we use lots map based (Geo) information. Almost every table has latitude and longitude. Working with this kind of data can be exciting and frustrating. This should give you a quick start into GIS with MySQL. “A geographic information system (GIS), or geographical information system, is any system that captures, stores, [...]
MySQL seems to be happy to convert types for you. Developers are rushed to complete their project and if the function works they just move on. But what is the costs of mixing your types? Does it matter if your are running across a million rows or more? Lets find out. Here is what the [...]
If your MySQL server has hundreds of clients (applications) and tens of thousands of queries per second, MySQL default network settings may NOT be for you. Network performance is not often a significant factor in the performance of MySQL. That said, there are things to consider. If you are building new applications make these changes [...]
(Re-posted from Florian’s blog.) MySQL replication support for the Pacemaker cluster manager (the stuff that we explained in this webinar) has made it into the Linux-HA resource agents default branch. If you are interested in testing — and you should! — please read the extended announcement. Feedback is extremely welcome on the linux-ha-dev mailing list. [...]
I get ask, by application developers, “how do you optimize MySQL”. I do lots of things that don’t really relate to a developer. I analyze the percent of queries are being pulled from cache for instance. What a developer can do to optimize the SQL they develop is a different questions. So here is a [...]