In SQL Server, multiple transactions are constantly running, and during performance contention, identifying the root cause quickly is crucial. One of my go-to methods is using the following DMV query to capture a snapshot of the current activity. This helps pinpoint blocking reads, query durations, and the users executing them.
While troubleshooting, this query serves as an audit trail, allowing me to revisit and analyze recurring issues. More importantly, it provides the actual query execution plan, making it easier to compare performance changes over time. If a specific query starts behaving differently, having this snapshot ensures I can track variations and optimize accordingly.