Let's see an example of exercise you can face during a job interview, and let's use it to understand some concepts about code optimization, time complexity and the famous Big-O notation ...

read the full post

Introduction

I've always used some kind of javascript framework when developing frontend stuffs. Mootools, jQuery, extjs and friends. All such frameworks provide a set of useful functionality, but above all in my opinion, they provide what is crucial for a web developer: cross browser compatibility.
The time you'll spend in writing cross browser code, even for a small project, is huge, especially if your software must support IE<9, and especially at the beginning, since you need to learn all browser ...

read the full post

Recently I've discovered a quite big perfomance problem when running INFORMATION_SCHEMA queries on mysql.

In particular I found that on some systems (some mysql versions) a query like

SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'db_name' AND TABLE_NAME = 'db_table'

can take up to 0.1s to run!

Clearly such time interval is not acceptable, and I think it happens only with some versions of mysql because I've run some tests on my local machine and on the server where this site is running obtaining a result of 0.0007 seconds, we are talking about a difference of two orders of magnitude!

I've not investigated more about which mysql versions are affected and if there are any patches, I ...

read the full post