Also, how big are the data sets you are working with? Would it be possible for each child process to make an in-memory copy of the data set, or possibly a temporary copy on disk? If there is some kind of file locking occurring, even though you aren't editing the data, maybe giving each child process its own copy of the data to work on would work around the issue. Clunky, but you will still need a workaround if this is being caused by a bug.
... View more