The tracking data for each action and task are stored in the dbo.WorkflowLog table when you have verbose logging enabled. This allows you to see additional variable information and other details in the Workflow history page.
The “dbo.WorkflowLog” table on Nintex databases stores the verbose logging that is set per workflow. We highly recommend that you turn Verbose Logging off unless we have specifically asked you to turn it on to diagnose an issue due to the amount of system resources it consumes.
To disable verbose logging globally
1. Go to Central Admin > Nintex Workflow Management > Global Settings and un-tick the “Enable Verbose Logging” option. This will disable the option on all current and new workflows.
To clean up the dbo.WorkflowLog tables
Open SQL Server Management Studio, connect to the Nintex Workflow databases and truncate the databases by performing the following steps:
1. Make sure that verbose logging is OFF, Central Admin > Nintex Workflow Management > Global Settings and un-tick the “Enable Verbose Logging” option.
2. Perform an IISReset
3. Restart the SharePoint Timer Service
4. Execute the following SQL command on you Nintex Databases:
DECLARE @return_value int
EXEC @return_value = [dbo].[PurgeVerboseLogs]
@DaysToKeep = 0
SELECT 'Return Value' = @return_value
This above command will clear all of the records from that table (should be 0 after it is finished). If anything is still trying to write to that database when you run the stored procedure, it will lock the table and anything else that is relying on it. Performing an IISreset/timer service restart will ensure that the verbose logging is truly off and help prevent this from happening.