Archive for November, 2011

I have found that there is often confusion on exactly what these mean. The short answer is this: The access is the where clause used to locate the rows, which are then subject to further inclusion (filtering) by the another secondary column that wasn’t the main driver in finding rows. I think the confusion... »

While troubleshooting a high CPU utilization problem recently, I found that half the sessions using a given database service were using a high amount of CPU, while the other were using a normal amount. Since I knew they were each running the exact same code, the logical conclusion was that the data differed. I... »

It is theoretically possible (although unlikely in a well managed system) to cause a large amount of transaction logging to occur if you do something as simple as update a row in one session, don’t commit, and repeatedly query that same row from another session. How is this possible? Let’s assume we have a... »

I was asked a good question (by a real doubter) asking me to prove Oracle’s ability to provide consistent reads. However, in the past I have been surprised at the number of fairly senior Oracle professionals that can’t come up with a simple test case. Below is such a case. We start by creating... »