'Commentary' Category

• To NULL or NOT to NULL that is the question.

  January 27, 2012

  I liked Shlomi Noach post on “IS TRUE and IS FALSE“.  This kind of logic create bugs. What will this return? select if((1 = true) and ( 1 is TRUE) and (NULL is not TRUE), TRUE, FALSE) as answer; You should know, NULL is never TRUE or FALSE but NULL is always NOT TRUE or [...]

  posted in Commentary by mark

• The State of High Availability

  January 25, 2012

  Searching for the Holly GrailFor months I have been writing and rewriting an blog post called “The Full Monty”. It’s a kind of how to build complete production system from scratch. I’m still not done. Maybe I’m fullish thinking I can build a one type fits all database server. But that’s not the problem. I’ve [...]

  posted in Commentary, DRDB, HA by mark

• Install mysql-master-ha (MHA) on CentOS

  December 1, 2011

  MySQL doesn’t often crash, but, if you use MySQL on a production system you should have High Availability. Maybe you’ve not heard of MHA.  Yoshinori Matsunobu only released it in July of this year (2011).  I’ve been reviewing it and I think you should too. There are a lot of people chasing after this “holy [...]

  posted in Commentary by mark

• Simplified MySQL SSL connections

  November 22, 2011

  In last weeks OurSQL postcast (episode 65)  Sheeri,  Sarah and Jerry talked about making MySQL safe with SSL.  Encryption always seems to be such a confusing subject. I think every database should be using SSL by default.  So, I was wondering just how easily SSL could be setup. Most existing examples I found  setup SSL authentication and encryption.  If you are handling  PCI [...]

  posted in Commentary by mark

• The Full Monty- Part 3

  October 21, 2011

  This is more boring parts but you must lay a good foundation. MySQL Setup: All the resources must be in place before you configure Pacemaker. The default location for MySQL data is /var/lib/mysql.  You will be moving this to the DRBD file system in /data/mysql.   The default MySQL configuration is in /etc/my.cnf.  I move it [...]

  posted in Commentary by admin

• The Full Monty- Part 2

  August 15, 2011

  Installing DRDB in CentOS 5.6. In Part 1 I when through the process of preparing a number of CentOS 5.6 servers. Now make the services they’ll preform more stable. High Availability (HA) I’ll be presenting two ways to provide redundant data and high available services. First, Pacemaker – with DRDB will duplicate your data at [...]

  posted in Commentary by admin

• Update to AutoMySQLBackup.sh

  January 28, 2011

  For a long time I though the AutoMySQLBackup project had died.  Then, after I created many updates, in November of last year I saw some life. Meanwhile, I have continued to update the code and track what people have requested.   Low volume project are sometimes hard to keep alive. People think the project is dead [...]

  posted in Commentary by mark

• It’s about Time.

  January 27, 2011

  WHAT TIME IS IT? This post started with a simple question: “Does the function NOW() get executed every time a row is examined?” According to the manual,  “Functions that return the current date or time each are evaluated only once per query …. multiple references to a function such as NOW() … produce the same [...]

  posted in Commentary, Tips & Tricks, Tunning by mark

• HandlerSocket plugin – NoSQL/SQL interactions

  December 28, 2010

  HandlerSocket is cool. But, it turns out there are a few issues. Justin Swanhart points out HandlerSocket currently lacks atomic operations . Since HandlerSocket uses different connections for reading and writing, you can’t increment/decrement a value without creating a race condition. Still, the idea of skipping SQL interpretation and just reading the data you know [...]

  posted in Code, Commentary by mark

• Using HandlerSocket Plugin for MySQL with Perl

  December 23, 2010

  In my last post I installed the HandlerSocket plugin into MariaDB and tested it.  Like the last post these examples are done with Linux CentOS 5.5. HandlerSocket some with Perl code for the Net:: module group. When you build and install the HandlerSocket plugin it does not build the Perl module. I looked and it [...]

  posted in Commentary, HOW TO by mark