Restrictions for Initializing Databases Asynchronously

You cannot initialize certain databases asynchronously, even if you explicitly use the async_init parameter.

Databases such as:
- All system databases
- All temporary databases, system or user
- Archive databases
- Proxy databases
- Any database created with the for load option
These commands cannot be run in a database that it still undergoing initialization:
- unmount database
- alter database ... log off
You can put the database into single user mode during initialization. However, the initializer does not run while the database is in single user mode, and is automatically restarted to continue initialization when you take the database out of single user mode.

Note: You may notice a slight performance impact to DMLs that use the space in the database being initialized while the asynchronous initialization service task is running.