(Baron Schwartz) There’s a really important difference between a unique index (MySQL’s answer to a “unique constraint”) and a primary key in MySQL. Please take a look at this:

(Peter Zaitsev) I often see people confuse different ways MySQL can use indexing, getting wrong ideas on what query performance they should expect. There are 3 main ways how MySQL can use the indexes for query execution, which are not mutually exclusive, in fact some queries will use indexes for all

(Rob Gravelle) When I first took on the role of reports designer for our systems, my first instinct was to try fetching all of the required fields in one huge SQL statement. I soon learned that there are better and easier ways to structure a query that will minimize the complexity while raising our

(Chris) Well, the answer I always get is “DROP”. Then I would say… “what if you wanted to preserve your data?” It is very common for DBAs to think only in terms of what is obviously available in MySQL, ALTER, than all of the tools that are really there. I have been placed in situations in many com

(Peter Zaitsev) It is rather typical for systems to start as MyISAM but as system growths to move to Innodb. The reason of the move could be just desire for better data consistency guaranty or being bitten repairing multiple GB MyISAM table few times, though Table Locks is probably the most importan

(Frazer) MySQL Cluster is the name given to one or more MySQL Server processes, connected to an Ndb Cluster database. From the point of view of the MySQL Server processes, the Ndb Cluster is a Storage Engine, implementing transactional storage of tables containing rows. From the point of view of the

(Ronald Bradford) MySQL provides a level of statistics for your INSERT, UPDATE, DELETE, REPLACE Data Manipulation Language (DML) commands using the STATUS output of various Com_ variables, however it is per server stats. I would like per table stats.

(Sarah Sproehnle) There is thorough documentation about the Partitioning feature in MySQL 5.1. There are also nice articles like this one by Robin. However, I thought it would be useful to have a quick “how-to” guide to partitioning by dates. I’ll use the world schema to keep it easy.

(Dimitri) After my previous post about InnoDB Doublewrite Buffer impact I’ve received several feedbacks where people are claiming to see an important performance degradation when they enabling doublewrite… Discussing with them about their wokloads I’ve tried to reproduce a similar activity with db

(Sarah Sproehnle) MySQL’s query cache is somewhat unique and can be very beneficial to certain applications, such as web apps that run the same queries over and over. If you’re unfamiliar with the query cache, here are some key points: