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Tips
Check for Updates
Periodically, DMT Software issues updates for SQL Block Monitor. For example:
- free maintenance upgrades
- major upgrades that you can purchase
- notifications to inform you about new products or offers from DMT Software
To check for any updates that are available for download:
- On the Help menu, click Check for Updates.
- Ensure that you are connected to the Internet, and then on the Online Update dialog box, click Check for Updates.
The updates that are available are listed.
- Click Install to update.
What is Process Blocking?
SQL Server blocking occurs when one connection (user process or application process) places a lock on a table (or a number of rows) and a second connection attempts to read or modify the data under the lock. Depending on the type of the lock, this can cause the second connection to wait until the first connection releases its lock. A blocked connection waits indefinitely for the blocking connection to release its lock.
The more blocking happens on the server the less concurrency the system achieves. A certain amount of blocking is unavoidable but too many blocks for longer periods of time can degrade the performance of SQL Server.
The combination of two blocked connections where the first is blocking the second and the second is blocking the first is called a deadlock. Since deadlocks are not naturally resolved with time, SQL Server automatically kills one of the processes (Deadlock victim) once it detects a deadlock. This allows the other process to continue with its transaction.
Although deadlocks can be caused by two short blocks (In a fraction of a second), it is the long blocks that usually increase the chances of a deadlock. Deadlocks are reported in Teratrax Performance Viewer in a separate node, however, a correlation between the Process Blocking node and the Deadlocks node is crucial in learning more about the events that lead to a deadlock.
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