made num_cores more strict to prevent too many connections

Data/Utils/HeuristicUtils.py

@@ -66,7 +66,7 @@ def extract_most_blamed_commit(heuristic_mapping):
 
 
 def main():
-    num_cores = os.cpu_count()
+    num_cores = min(os.cpu_count(), 150)
     db_repo = DBRepository()
     mappings = db_repo.get_all_entries_with_heuristic_mapping()
     chunk_size = calculate_chunk_size(mappings, num_cores)