Microsoft Sql Server Database Configuration
Microsoft SQL Server implements the isolation level
than most databases and does not interact well with the process engine’s
optimistic locking scheme.
As a result you may suffer deadlocks when putting the process engine under high load.
If you experience deadlocks in your MSSQL installation, you must execute the following statements in order to enable SNAPSHOT isolation:
ALTER DATABASE [process-engine] SET ALLOW_SNAPSHOT_ISOLATION ON ALTER DATABASE [process-engine] SET READ_COMMITTED_SNAPSHOT ON
[process-engine] contains the name of your database.