Re: What is SPIN_COUNT?

spin_count is the number of times an Oracle process will attempt to get a latch.
Basically Oracle will try to aquire a latch, if it is busy the Process will spin and then attempt to acquire the latch again. It will do this until it either aquires the latch or reaches spin_count. If it reaches spin_count then the process goes to sleep for a set amount of time and the wakes up and starts the process again. The higher the number the longer an Oracle process will spin waiting on a latch, and the more likely it will be to get the latch without
sleeping. However the Oracle process will use more CPU cycles waiting on the latch. It is my understanding that oracle has not changed this parameter, ie. increased it's default, even though the processing power of CPUs has increased. I would imagine they have not changed the parameter, because it is difficult for
them to target the parameter to a specific CPU. Therefor on some systems with more powerful CPUs might benefit from changing this parameter from the default,
which I believe is 2000.

Mike H. Received on Tue Jul 11 1995 - 00:00:00 CEST