This is an issue that keeps rearing its ugly head over and over again, and since it greatly affects performance, it is most important that DBAs of any DMBS running on Linux come to grips with it. So I decided to do some research and try different settings on my notebook. Here are my findings.What can you find on the web?A Wikipedia search for the word swappiness will come up empty (any volunteers out there want to write an article?). A Google search will show some pretty old material---the best article I found is from 2004: Linux: Tuning Swappiness. This article includes a detailed discussion with some interesting remarks by Andrew Morton, a Linux kernel maintainer.So, what is swappiness?

Lenz Grimmer recently wrote two blogs about password security on MySQL. Both are worth reading in detail. You'll find them in Basic MySQL Security: Providing passwords on the command line and More on MySQL password security. Although I wrote a comment on the latter one, there is one point I thought was worth its own blog.

When using Oracle, the data dictionary provides us with tons of tables and views, allowing us to fetch information about pretty much anything within the database. We do have information like that in MySQL 5.0 (and up) in the "information_schema" database, but it's scattered through several different tables.Sometimes a client asks us to change the datatype of a column, but forgets to mention the schema name, and sometimes even the table name. As you can imagine, having this kind of information is vital to locate the object and perform the requested action. This kind of behaviour must be related to Murphy's Law.In any case, I'd like to share with you a simple stored procedure that has helped us a lot in the past.

There's no video for Jacob Nikom's December 2007 Boston MySQL User Group meeting, but the slides for "Measuring MySQL Server Performance" can be downloaded (2.33 MB) at http://technocation.org/files/doc/Measuring_MySQL_server_performance_03.pptAnd with that, this is (I believe) post #10,000 at Planet MySQL!

Hi All!This year, the International Free Software Forum celebrated its 10th anniversary. It happened last week in Porto Alegre.Pythian presented a session on Thursday called 8 Rules for Designing More Secure Applications with MySQL. As promised, here are the slides we used on that session:

I was recently asked a question by someone who had attended my Shmoocon talk entitled "Why are Databases So Hard to Secure?". PDF slides are available (1.34 Mb). I was going to put this into a more formal structure, but the conversational nature works really well. I would love to see comments reflecting others' thoughts.I found several things of interest in your talk about database security and several new things to think about.In particular I realized that DBMSs have at least two hats in the world of software architecture namely as technical services ("smart file system") and as application framework. Perhaps that "depth" is one of the reasons why dbms is hard to secure? For example, considering just the question of who or what have user roles within a DBMS deployment. From the "deep" point of view, the "user" could be an application, or a module, or just the next layer up  []

Here are the slides and links I am using for the "Database Security Using White-Hat Google Hacking" at the 2008 MySQL Users Conference and Expo.pdf slidesWhere to Start:http://johnny.ihackstuff.com/ghdb.phpi-hacked.com/content/view/23/42

The Oracle gateway for ODBC provides an almost seamless data integration between Oracle and other RDBMS. I won't argue about its performance, limits, or relevance. It serves a few purposes; set it up and you'll be able, for example, to create database links between Oracle and MySQL. After all, wouldn't it be nice if you could run some of the following SQL statements? "select o.col1, m.col1 from oracle_tabo, mysql_tab@mysql m where o.col1=m.col1;" "insert into oracle_tab (select * from mysql_tab@mysql);"This post is intended to share, the same way Karun did it for SQL Server last year, some tips related to the setup of the Oracle Gateway for ODBC with MySQL Connector ODBC on Linux.PrerequisitesI've installed all the configuration on my laptop to test it. It's running Ubuntu Intrepid Ibex 32bits, but I won't dig into the challenge of installing the MySQL Connector ODBC 5.1 on it. All I'll tell you is that, if  []

If you are using InnoDB Hot Backup utility and the innobackup.pl wrapper script, be very careful if you are not running backups under the system "mysql" user. There is a bug which causes InnoDB Hot Backup to sometimes report a successful backup when it actually failed.

Slaves can be used for:Horizontal read scalability -- take the load off a master database by spreading reads to a replicated slave.Disaster recovery -- some disasters, such as a hardware failure, can be solved by having a slave ready to propagate to a master. This technique also works to make offline changes to a master/slave pair without having database downtime (see below).Consistent Backups -- without disrupting production usage, a slave can be used to ta

REPLACE does the equivalent of "find and replace".

This article provides a list of the measurements the popular MySQL cacti plugin monitors, and gives a DBA a guideline of what other monitoring products or custom monitoring should be looking at providing.

From the post: "It turns out that as part of the MySQL upgrade, the path to the MySQL installation changed (or a symlink was removed, or something to that effect) - at any rate, /usr/local/mysql no longer existed." Talks about the problem and how to fix it.

Continuent CTO Robert Hodges talks about future of database clustering and how Tungsten open source project fits in that picture

Some trick : how to generate/use a table of (not necessarily sequential) numbers from a mysql server.

Several methods to generate 4 billion records quickly

How to create one million records from a set of NULL values. And several alternative methods to achieve the same result

An example showing how to use Sphinx when MySQL Full Text Search limitations show up.

An useful collection of places where you can find data available for benchmarks

good tips on how to solve this problem.