old_contents: import logging
  
  from django.core.management.base import BaseCommand
  from django.db import transaction
  
  from document.models import Document
  from document.models import Submitter
  
  logger = logging.getLogger(__name__)
  
  
  class Command(BaseCommand):
  
      def handle(self, *args, **options):
          self.do()
  
      @transaction.atomic
      def do(self):
          submitters = Submitter.objects.all()
          documents = Document.objects.all()
          counter = 1
          n_docs = documents.count()
          print(n_docs)
          for document in documents:
              print('document ' +  str(counter) + '/' + str(n_docs))
              doc_submitters = submitters.filter(document=document)
              person_ids = []
              for doc_sub in doc_submitters:
                  if doc_sub.person.id in person_ids:
                      doc_sub.delete()
                  else:
                      person_ids.append(doc_sub.person.id)
              counter += 1
  
new_contents: import logging
  
  from django.core.management.base import BaseCommand
  from django.db import transaction
  
  from document.models import Document
  from document.models import Submitter
  
  logger = logging.getLogger(__name__)
  
  
  class Command(BaseCommand):
  
      def handle(self, *args, **options):
          self.do()
  
      # @transaction.atomic
      def do(self):
          submitters = Submitter.objects.all()
          documents = Document.objects.all()
          counter = 1
          n_docs = documents.count()
          print(n_docs)
          for document in documents:
              print('document ' + str(counter) + '/' + str(n_docs))
              doc_submitters = submitters.filter(document=document)
              person_ids = []
              for doc_sub in doc_submitters:
                  if doc_sub.person.id in person_ids:
                      doc_sub.delete()
                  else:
                      person_ids.append(doc_sub.person.id)
              counter += 1
  
subject: Remove atomic transaction from command to reduce memory usage