@Eaven HUANG
We could check the following registry value in the WSUS Server to confirm the type of the database we used.
HKLM\Software\Microsoft\Update Services\Server\SetupSqlServerName
SQL Server database:
WID database:
Reference link:
https://learn.microsoft.com/de-de/security-updates/windowsupdateservices/18127574
In addition, please try to follow the below link to maintenance if you haven't tried for a long time.
https://learn.microsoft.com/en-us/troubleshoot/mem/configmgr/wsus-maintenance-guide#help-my-wsus-has-been-running-for-years-without-ever-having-maintenance-done-and-the-cleanup-wizard-keeps-timing-out
Hope the above will be helpful.
Have a great weekend.
Regards,
Rita
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