Blocked Session History

The metrics in this category capture sessions that are currently blocked, together with the blocking session and the query text involved, so that lock contention can be diagnosed.

Evaluation and Collection Frequency — Every 30 Minutes

Table 2-6 Blocked Session History Metrics

Metric	Description
Blocked Session ID (key column)	Session ID (SPID) of the session that is being blocked.
Database Name	Name of the database in which the blocked session is executing.
Blocking Session ID	Session ID (SPID) of the session that holds the resource the blocked session is waiting on.
Blocked Query Text	Text of the SQL statement being run by the blocked session.
Blocking Query Text	Text of the SQL statement being run by the blocking session.
Wait Resource	Description of the resource on which the blocked session is waiting.
Blocked Time (ms)	Length of time, in milliseconds, that the session has been blocked. Set the warning and critical thresholds to be alerted when blocking persists.