For instance a user will have a userid and a importuserid once they are imported. The userid is the vBulletin assigned userid and will be what ever is next in the line and available as per the database.
The importuserid is the userid from the source board.
This is imported and used to match the user to their imported posts, attachments PM's etc.
The same goes for posts for instance threadid has a importthreadid so that ImpEx knows where to put the imported posts.
When you have done an import and are completely finished and wish to do another import you will have to set all these import id's to 0.
This is so that you finalized the data in the board, that is remove its legacy id's so that it permanently becomes part of the target board, after this is done, there is no way back (apart from restoring the back up you made before starting).
As you can import into an empty board or an existing one, this has some serious implications. e.g.
You have a source board and your vBulletin target board.
The vBulletin target board has a lot of content, once you have performed an import of the source board you can still reverse the operation as the source database has importsomethingid's for all the imported data, therefore ImpEx can tell what is original and what is imported data, this is needed for the re-running of modules also.
As soon as you finishing an import, the import id's are no longer needed and serve no purpose, with one exception, that being 3rd party applications.
If you have an application that uses the user data from your source board, it will no doubt be associated with the userid from the source board, if you wish to keep that, update the 3rd party application to use the importuserid in the vBulletin database. Though vBulletin will not update the importuserid only the userid for new users so its best to update the 3rd party software with the new userid's.
So with the exception of 3rd party applications there is no more use for the import id's.
They can be ignored for all purposes save Importing consecutive boards and general tidiness (also indexes are created that may slow down huge boards slightly).
You MUST remove the import id's before performing a 2nd import, this is because ImpEx will not know what is original imported data and what is just imported etc.
If you are importing boards that use the same user data, just use the auto-email associate to link up the userids automatically between board imports.
To remove the import id's use the clean database found at the top of the ImpEx page, as show in the attached images.
