DPA shows blocking from two different perspectives, Top Root Blocker SQL and Top Waiting SQL. The top root blocker report is shown underneath the main trend charts and shows the SQL causing the most blocking issues, i.e. the culprit of the blocking and the SQL you need to possibly tune to alleviate blocking problems. This data is shown in the GUI on this chart underneath the main trend and anomaly charts:
However, to find out more information about these queries, you need to click into the query and several more times to get to the program running the query, the machine it came from, the database it was running in, the login username, etc. The attached custom query will provide the details shown in the chart, but also provide the extra supporting information as well.
This query also shows Top Root Blockers across all instances being monitoring, so the worst offender in your entire fleet will be quickly diagnosed.
Note: edit the first 2 lines to pick a date/time range, and the script should run without any further changes
