(Vladimir Kolesnikov) Assume you have a table with about 300 000 rows, and an indexed column ecol1Πwith only 9 distinct values. Now you got a query like fselect * from t1 where col1 = constf. The questions are Рwhen the index is faster to full table scan and vice versa? Рdoes MySQL use th

(Leo Hsu and Regina Obe) Simon Greener, wrote an article on how to load GPX xml files into Oracle XMLDB. That got me thinking that I haven’t really explored all the XML features that PostgreSQL has to offer and to some extent I’ve been reticent about XML processed in any database for that matter.

Shlomi Noach recently wrote a useful primer on the depth of B-trees and how that plays out for point queries—in both clustered indexes, like InnoDB, and in unclustered indexes, like MyISAM. Here, I’d like to talk about the effect of B-tree depth on insertions and range queries. And, of course, I’l

(Shlomi Noach) Writing up some scripts, I see more and more ambiguities with regard to global variables.

(Giuseppe Maxia) About a month ago, I published the results of MySQL 5.x performance with logging. The results covered several versions, from 5.0.45 to 5.1.33. Among the conclusions of the post was the consideration that MySQL 5.0.x is faster than MySQL 5.1 in read only operations. I hinted that bet

(Joe Izenman) One of the common needs for a content management system (hey, that’s what we make!) is some form of page ordering. Clients need to be able to manually order pages to suit their fancy, rather than relying on something arbitrary like update time or alphabetical order. For this we use a s

(Robin Schumacher) Although MySQL 5.1 was released in December of 2008, Sun Microsystems isn’t wasting any time moving forward with a number of new and exciting enhancements for its next release, MySQL 5.4. The first item of note is that the MySQL Server will be returning to a release early/often pa

(Leo Hsu and Regina Obe) Different Linux distros have their preferred place of where stuff goes and of course the default location on windows is completely different from that too. So there isn’t really one default location where you can find PostgreSQL data cluster. Of course user’s can pick their

(Dathan Pattishall) So say you have two mySQL servers called A and B. A and B are in a circular replication ring meaning A replicates from B B replicates from A

(George J. Trujillo Jr.) A number of developers look at SQL tuning hints as a way to performance tune queries. Where the best way to tune SQL code is not to use hints. Hints add high maintenance code and try to influence the Cost Based Optimizer which can have negative impacts in the future. What if