What is the proper way of importing closed PWO from one environment to the next?


As part of a migration from v6.1.2 to v8.0.1, we have to migrate some data, including notable closed PWO.
By closed PWO, we mean PWO which have an OrderState in a viPWOOrderState with isClosed = 1 (OrderState IN (SELECT orderstate FROM viPWOOrderState WHERE IsClosed = 1).

We know that we could just keep the v6 database live for a couple of years and query it for audit purposes, but our customer would like to have the data available in its new environment (mainly to avoid displaying incomplete data to the users in the web portal).

We could do it with the DataImport tool, assign a self-service workflow to all AccProduct and wait for the PWO to all be "assigned" and then aborting them manually, but this would be painfully slow, considering the number of closed PWO we have to deal with (hundreds of thousands). IT would also trigger all the assignations and then remove them, which would mean additional processing, and additional time...

We tried to do it with a raw SQL import, thinking that this would not cause any problem since the closed PWO are (supposedly) inert objects... However this was not the case: after the import, the DBQueue kept creating "Get approver for a request" tasks for these PWO, and we had to delete them otherwise our database would be unusable.

Any idea of a quicker solution for this use-case?
Thanks anyone for your help!