A user-created stored procedure executes when free space on a segment drops below the threshold maintained by Adaptive Server.
All databases have a last-chance threshold on the log segment, which is an estimate of the number of free log pages that are required to back up and truncate the transaction log. The last-chance threshold (LCT) is a defined amount of available space; a specified number of free pages on a log segment.
The LCT also defines the action to be taken when the amount of space falls below the specified threshold value. This threshold monitors free space within a database, preventing the transaction log from running out of space.
When you add a threshold to a segment, you must specify the stored procedure used to monitor this threshold. By default, Adaptive Server uses sp_thresholdaction for the last-chance threshold.
For users, threshold maintenance in cluster processing is indistinguishable from that of a nonclustered Adaptive Server. However, there are some changes in dbcc commands, described below.
