Dear Philippe,
Firstly, allow me to say that the work put in SPMF is amazing. Grateful to have such an open source tool available for research.

I would like to describe an issue I am facing while running SPADE and PrefixSpan algorithms for sequential pattern mining.

When running the algorithms on a database, a .tmp file is created after some time has elapsed (I have not determined how much time this is), in the directory and with file name as specified in the OutputFilePath argument. I was wondering why this is happening and at which step of the algorithm this .tmp file generation is created.

The above issue kept happening while running the aforementioned algorithms on a database with total number of sequences 32K, 3K distinct items, with mean (sd) of sequence length 490(459) and median number of itemsize 5. The size of the .tmp file created was 3TB after which I had to stop the algorithm from proceeding.

Your help to understand why this is happening would be valuable.

Kind regards, Solomon