Global variables

This section describes changes to global variables.

**Table 13-4: Global variables added for the Cluster Edition**
Global variable	Definition
@@instanceid	Returns the id of the instance from which it was executed.
@@active_instances	Returns the number of active instances in the cluster.
@@clusterboottime	Returns the date and time the cluster was first started, even if the instance that originally started the cluster start has shut down.
@@clustercoordid	Returns the instance id of the current cluster coordinator.
@@clustermode	Returns the string: “shared-disk cluster”.
@@clustername	Returns the name of the cluster.
@@instancename	Returns the name of the instance from which it was executed.
@@jsinstanceid	Id of the instance on which the Job Scheduler is running, or will run once enabled.
@@quorum_physname	Returns the physical path for the quorum device.
@@system_busy	Number of ticks during which Adaptive Server was running a system task¹.
@@sys_tempdbid	Returns the database id of the executing instance’s effective local system temporary database.
@@system_view	Returns the session-specific system view setting, either “instance” or “cluster”.
@@user_busy	Number of ticks during which Adaptive Server was running a user task¹.

¹The value of @@user_busy + @@system_busy should equal the value of @@cpu_busy

Considerations for global variables in a clustered environment

For @@servername, the Cluster Edition returns the name of the cluster, not the instance name. Use @@instancename to return the name of the instance.

In a nonclustered Adaptive Server environment, the value for @@identity changes for every record inserted. If the most recent record inserted contains a column with the IDENTITY property, @@identity is set to the value of this column, otherwise it is set to “0” (an invalid value). This variable is session-specific, and takes its value based on the last insert that occurred during this session.

In a clustered environment, multiple nodes perform inserts on tables, so the session-specific behavior is not retained for @@identity. In a clustered environment, the value for @@identity depends on the last record inserted in the node for the current session and not on the last record inserted in the cluster.