Hi,
as far as I know you will not find it in the reporting database.
But can find it in the published database. You have to use the table MSP_Assignments. Here you find a column WASSN_LOCKDOWN_BY_MANAGER.
You can do a
SELECT * from MSP_EPMTask T inner join ProjectServer_Published.dbo.msp_assignments A on T.taskuid=A.Task_UID where A.WASSN_LOCKDOWN_BY_MANAGER = 1
The "close task to update" is similar to the statusmanager field - you set it on a task level, but in the database it is stored on assignment level.
Hope that helps
Regards
Christoph