Summary information |
|
|---|---|
Default value |
Platform-specific |
Range of values |
Platform-specific minimum–1000000, in multiples of default value |
Status |
Static |
Display level |
Comprehensive |
Required role |
System Administrator |
sql server clock tick length specifies the duration of the server’s clock tick, in microseconds. Both the default value and the minimum value are platform-specific. Adaptive Server rounds values up to an even multiple of n, where n is the platform-specific clock-tick default value. You can find the current values for sql server clock tick length by using sp_helpconfig or sp_configure.
In mixed-use applications with some CPU-bound tasks, decreasing the value of sql server clock tick length helps I/O-bound tasks. A value of 20,000 is reasonable for this. Shortening the clock tick length means that CPU-bound tasks will exceed the allotted time on the engine more frequently per unit of time, which allows other tasks greater access to the CPU. This may also marginally increase response times, because Adaptive Server runs its service tasks once per clock tick. Decreasing the clock tick length means that the service tasks will be run more frequently per unit of time.
Increasing sql server clock tick length favors CPU-bound tasks, because they execute longer between context switches. The maximum value of 1,000,000 may be appropriate for primarily CPU-bound applications. However, any I/O-bound tasks may suffer as a result. This can be mitigated somewhat by tuning cpu grace time (see “cpu grace time”) and time slice (see “time slice”).
Changing the value of sql server clock tick length can have serious effects on Adaptive Server’s
performance. You should consult with Sybase Technical Support before
resetting this value.
