> I'm wondering if having multiple instances of pqinsert, possibly firing
> simultaneously, would run the risk of corrupting the product queue, or
> is LDM designed to handle such a situation?
The LDM (actually, the product-queue library) is specifically designed
to handle concurrent access -- so your situation won't be a problem.
Remember to run the pqinsert(1)s out of the LDM configuration-file via
the EXEC action so that the SIGCONTs generated by the pqinsert(1)
processes upon insertion of a data-product are sent to to other
processes of the LDM system.