DBADash Blocking

[aachaemenes]

The blocking graph under performance tab. can we add changing threshold for blocking there or is it going to show any blocking?

[DavidWiseman]

The blocking bubble chart shows data from the running query snapshots. This is a point-in-time snapshot of what was happening on your server at the time of the collection. If there was blocking, a bubble is plotted on the chart. The size of the bubble is larger /smaller based on the wait duration, and the higher up in the chart with more blocked queries. If you select a long period, the top 500 points are plotted. Clicking on a bubble will show you the associated running queries snapshot which will allow you to diagnose the root cause of the blocking.

If you don't see blocking on this chart it doesn't mean you have no blocking on your SQL instance. Blocking that occurs for a very short duration might not get picked up by the running query snapshots. If you want to see all blocking, the wait stats are probably the best place to do this. On the performance tab, you can set a string filter for "LCK" which will allow you to see the lock waits. The Waits tab can provide additional info.

Hope this helps