Summary information |
|
|---|---|
Default value |
200 |
Range of values |
2–value of row lock promotion HWM |
Status |
Dynamic |
Display level |
Intermediate |
Required role |
System Administrator |
row lock promotion LWM (low-water mark), together with the row lock promotion HWM (high-water mark) and row lock promotion PCT specifies the number of row locks permitted during a single scan session of a table or an index before Adaptive Server attempts to promote from row locks to a table lock.
row lock promotion LWM sets the number of locks below which Adaptive Server does not attempt to acquire a table lock on the object. The row lock promotion LWM must be less than or equal to row lock promotion HWM.
For more detailed information on scan sessions and setting up lock promotion limits, see “Configuring locks and lock promotion thresholds” on page 286 in the Performance and Tuning Guide.
The default value for row lock promotion LWM is sufficient for most applications. If Adaptive Server runs out of locks (except for an isolated incident), you should increase number of locks. See the Performance and Tuning Guide for more information.
You can also configure lock promotion at the per-object level. See sp_setrowlockpromote in the Reference Manual.
