Does the order of files in JOINKEY matter for Many to Many match(Cartesian Product)? I ask this question in relation to ICE428A error message.
Is it because while matching 2 files, dfsort takes all the records in a stack and keeps looking for match on a second file and later writting matched record to the final output? If my file1 has 10000 records and file2 has only 2 or 3 records for a key, it tries to put all 10000 records in a stack then later performing match. This will be improved only if we change the order where in DFSort takes 2 or 3 records in a stack and then performs match.
I am not asking for actual algorithm for DFSort processing but just asking if the order of file does matter. If it does matter, I would always use file with lesser number of dups as the first one for performance improvement.
Earlier I was having impression that file order doesn't really matter for joinkeys.
Please excuse me if my understanding is wrong as its a complete imagination of how DFSort would have behaved.