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…
Using awk to extract bind variable values from a trace file
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…
Help! Select queries are…filling up my redo logs?!!
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…
Proving Oracle’s read consistent model
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…
HBase has disappearing rows
I guess this may have a place if your application data is transient in nature and doesn’t need to be retained forever. We first take an existing table and for a given column family set its “time to live” to…
Runtime connection load balancing issues in 11.2.0.2
We upgraded our largest and most important databases last month to 11.2.0.2 from 10.2.0.4. We had a few issues, most of which have been resolved. However, one that continued to plague us until yesterday is the apparent inability of any…