If you’re familiar with Neil Gunther’s Universal Scalability Law, you may have heard it said that there are two coefficients, variously called alpha and beta or sigma and kappa. There are actually three coefficients, though. See?
This would have to be one of the most common MySQL error messages that is misleading to the end user developer. The MySQL Manual page confirms the broad range of possible conditions, but offers little to a PHP developer that does not speak MySQL Geek. I am commonly asked to help solve this issue from a developer.
With Performance Schema improvements in MySQL 5.6 I think we’re in the good shape with insight on what is causing performance bottlenecks as well as where CPU resources are spent. (Performance Schema does not accounts CPU usage directly but it is something which can be relatively easily derived from wait and stage information). Where we’re still walking blind with MySQL is resource usage – specifically Memory Usage.
Moral of the upcoming story: when your systems rely on someone else’s software, make sure you test it thoroughly to understand how it works.
I found a couple of interesting things about the go-mysql-driver driver for Go. One is that it prepares every query before executing it, and then closes it afterwards, if you’re just using the db.Query() or db.QueryRow() functionality. There is zero benefit to this; Bill Karwin has probably listed it as an antipattern somewhere. I asked for one query, but I got three.
This is a recurrent question made by our MySQL Support customers:
How can I audit the login attempts in MySQL?
Logging all the attempts or just the failed ones is a very important task on some scenarios. Unfortunately there are not too many audit capabilities in MySQL Community so the first option to audit MySQL’s authentication process is to get all the information we need from logs.
Those who’ve been around the MySQL world are probably aware of the much-discussed topics of GPL licensing, dual licensing, and in particular, licensing of the client libraries (also called connectors or drivers) and the FOSS exception to that licensing. This is newly relevant with the announcement of a permissively-licensed MySQL-compatible client library for MariaDB.