Determining threshold placement

Each new threshold must be at least twice the @@thresh_hysteresis value from the next closest threshold, as shown in Figure 17-10:

Figure 17-10: Determining where to place a threshold

Graphic of a bar graph that shows the placement of the last chance threshold being twice the @@thresh_hysteresis value.

To see the hysteresis value for a database, use:

select @@thresh_hysteresis

In this example, a segment has a threshold set at 100 pages, and the hysteresis value for the database is 64 pages. The next threshold must be at least 100 + (2 * 64), or 228 pages.

select @@thresh_hysteresis

----------- 
        64

sp_addthreshold mydb, user_log_dev, 228, 
    sp_thresholdaction