According to the wikipedia page,

“The rack is a medieval torture . . . which induces excruciating pain as the victim’s joints slowly dislocate.”

Per the Oracle website,

“Oracle RAC is a cluster database with a shared cache architecture that overcomes the limitations of traditional shared-nothing and shared-disk approaches to provide highly scalable and available database solutions for all your business applications.”

Which is more painful, you might ask? I cannot say for certain, as I have never been subjected to the torture of a medieval rack, but I have experienced some pain at the hands of the Oracle RAC. My first encounter was about five months ago when I first became an “official” DBA. Being eager to jump into solving problems in my new job (as that’s what most DBAs do, solve problems), I relished the chance to get my hands dirty and work on a “real” DBA task — a database lock.

Even though I had never been officially titled a DBA before, I was somewhat familiar with the concepts as I have been working around them for years (and still chose to join their ranks, if that tells you anything). Theoretically, I knew exactly what a database lock was, but I had no clue how to practically diagnose or kill one off.

Checking with a few knowledgeable co-workers, I was directed to a set of common database diagnostic scripts affectionately known as the “Pythian Kit”. (more…)