The system table systhresholds holds information about thresholds; sp_helpthreshold uses this table. In addition to information about segment name, free page, last-chance status, and the name of the threshold procedure, the table also records the server user ID of the user who created the threshold and the roles the user had at the moment the threshold was created.
Adaptive Server gets information about how much free space is remaining in a segment—and whether to activate a threshold—from curunreservedpgs.
