Types of locks during Fastload abort-? - response (8) by ToddAWalter

Technically, there are no locks when Fastload or Multiload are not running - if the job has aborted or been halted prior to finishing. There is a status recorded in the table that says that the table is in process of being loaded. The status is left in the table to enable the job to be restarted, continue from where it left off and run to completion.
This status is simple to remove in the case of fastload because the only choices are to drop or delete all and reload the table.
Since there is already data in the table being multiloaded, there is more complexity. If the apply phase has not been started yet, then cleanup must be done but the table contents have not yet been affected. If apply phase has begun, then the table is in an uncertain state. It is not recommended to release the mload when the table is in that state but it is allowed with the additional option. Because of the added complexity, the release mload is a form of "are you sure" check before you put your table into an uncertain state or remove the ability to restart and complete the mload.
It is not possible to run concurrent fastload jobs into the same table at this time. It is on the to do list to allow multiple insert selects to insert into separate partitions via new functionalty being build to allow locks at the partition level - no release date available at this time.