old_contents: import sys
  import csv
  from optparse import make_option
  
  from django.core.management.base import BaseCommand
  
  from modoboa.core import load_core_settings
  from modoboa.core.models import User
  from modoboa.core.extensions import exts_pool
  from modoboa.core.management.commands import CloseConnectionMixin
  from ...models import Alias
  
  
  class Command(BaseCommand, CloseConnectionMixin):
      help = 'Export identities (mailbox and aliases) to a csv'
  
      option_list = BaseCommand.option_list + (
          make_option(
              '--sepchar', action='store_true', dest='sepchar', default=';'
          ),
      )
  
      def handle(self, *args, **kwargs):
          exts_pool.load_all()
          load_core_settings()
  
          csvwriter = csv.writer(sys.stdout, delimiter=kwargs['sepchar'])
          for u in User.objects.all():
              u.to_csv(csvwriter)
  
          for a in Alias.objects.all():
              a.to_csv(csvwriter)
  
new_contents: import sys
  import csv
  from optparse import make_option
  
  from django.core.management.base import BaseCommand
  
  from modoboa.core import load_core_settings
  from modoboa.core.models import User
  from modoboa.core.extensions import exts_pool
  from modoboa.core.management.commands import CloseConnectionMixin
  from ...models import Alias
  
  
  class Command(BaseCommand, CloseConnectionMixin):
      help = 'Export identities (mailbox and aliases) to a csv'
  
      option_list = BaseCommand.option_list + (
          make_option(
              '--sepchar', action='store_true', dest='sepchar', default=';'
          ),
      )
  
      def handle(self, *args, **kwargs):
          exts_pool.load_all()
          load_core_settings()
  
          csvwriter = csv.writer(sys.stdout, delimiter=kwargs['sepchar'])
          for u in User.objects.all():
              u.to_csv(csvwriter)
  
          for a in Alias.objects.prefetch_related('mboxes', 'aliases'):
              a.to_csv(csvwriter)
  
subject: Improve the speed of csv export file generation