The Sessions panel tracks the performance of the active and blocked sessions running on your monitored SQL Server. Unexpected spikes in the number of concurrent blocked sessions may warn you about the beginning of a serious performance issue. Chronically high blocked and deadlocked sessions are a significant performance concern. For additional information, see Get sessions performance summary.
Activity & Blocking chart
The Activity and Blocking chart shows the total number of active sessions on your monitored SQL Server instance and any blocking or deadlocks that may occur between sessions.
Why it is important
Indicates the number of active sessions on the SQL Server instance.
Indicates the number of sessions on the SQL Server instance being blocked by other sessions holding requested locks.
Indicates sessions that block at least one session, which can then block other sessions.
Indicates the total number of deadlocks on the SQL Server instance. A deadlock has no lead blocker and is circular in nature.
Client Computers gauge
The Client Computers gauge displays the total number of unique client computers connected to the SQL Server instance.